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Class: PG::Connection

Relationships & Source Files
Namespace Children
Modules:
Pollable
Super Chains via Extension / Inclusion / Inheritance
Instance Chain:
self, Pollable, Constants
Inherits: Object
Defined in: lib/pg/connection.rb,
ext/pg_connection.c

Overview

The PostgreSQL connection class. The interface for this class is based on libpq, the C application programmer’s interface to PostgreSQL. Some familiarity with libpq is recommended, but not necessary.

For example, to send query to the database on the localhost:

require 'pg'
conn = PG::Connection.open(:dbname => 'test')
res = conn.exec_params('SELECT $1 AS a, $2 AS b, $3 AS c', [1, 2, nil])
# Equivalent to:
#  res  = conn.exec('SELECT 1 AS a, 2 AS b, NULL AS c')

See the Result class for information on working with the results of a query.

Many methods of this class have three variants kind of:

  1. #exec - the base method which is an alias to #async_exec . This is the method that should be used in general.

  2. #async_exec - the async aware version of the method, implemented by libpq’s async API.

  3. #sync_exec - the method version that is implemented by blocking function(s) of libpq.

Sync and async version of the method can be switched by .async_api= , however it is not recommended to change the default.

Constant Summary

Constants - Included

CONNECTION_ALLOCATED, CONNECTION_AUTH_OK, CONNECTION_AWAITING_RESPONSE, CONNECTION_BAD, CONNECTION_CHECK_STANDBY, CONNECTION_CHECK_TARGET, CONNECTION_CHECK_WRITABLE, CONNECTION_CONSUME, CONNECTION_GSS_STARTUP, CONNECTION_MADE, CONNECTION_NEEDED, CONNECTION_OK, CONNECTION_SETENV, CONNECTION_SSL_STARTUP, CONNECTION_STARTED, DEF_PGPORT, INVALID_OID, INV_READ, INV_WRITE, InvalidOid, PGRES_BAD_RESPONSE, PGRES_COMMAND_OK, PGRES_COPY_BOTH, PGRES_COPY_IN, PGRES_COPY_OUT, PGRES_EMPTY_QUERY, PGRES_FATAL_ERROR, PGRES_NONFATAL_ERROR, PGRES_PIPELINE_ABORTED, PGRES_PIPELINE_SYNC, PGRES_POLLING_FAILED, PGRES_POLLING_OK, PGRES_POLLING_READING, PGRES_POLLING_WRITING, PGRES_SINGLE_TUPLE, PGRES_TUPLES_CHUNK, PGRES_TUPLES_OK, PG_DIAG_COLUMN_NAME, PG_DIAG_CONSTRAINT_NAME, PG_DIAG_CONTEXT, PG_DIAG_DATATYPE_NAME, PG_DIAG_INTERNAL_POSITION, PG_DIAG_INTERNAL_QUERY, PG_DIAG_MESSAGE_DETAIL, PG_DIAG_MESSAGE_HINT, PG_DIAG_MESSAGE_PRIMARY, PG_DIAG_SCHEMA_NAME, PG_DIAG_SEVERITY, PG_DIAG_SEVERITY_NONLOCALIZED, PG_DIAG_SOURCE_FILE, PG_DIAG_SOURCE_FUNCTION, PG_DIAG_SOURCE_LINE, PG_DIAG_SQLSTATE, PG_DIAG_STATEMENT_POSITION, PG_DIAG_TABLE_NAME, PQERRORS_DEFAULT, PQERRORS_SQLSTATE, PQERRORS_TERSE, PQERRORS_VERBOSE, PQPING_NO_ATTEMPT, PQPING_NO_RESPONSE, PQPING_OK, PQPING_REJECT, PQSHOW_CONTEXT_ALWAYS, PQSHOW_CONTEXT_ERRORS, PQSHOW_CONTEXT_NEVER, PQTRANS_ACTIVE, PQTRANS_IDLE, PQTRANS_INERROR, PQTRANS_INTRANS, PQTRANS_UNKNOWN, PQ_PIPELINE_ABORTED, PQ_PIPELINE_OFF, PQ_PIPELINE_ON, SEEK_CUR, SEEK_END, SEEK_SET

Class Attribute Summary

Class Method Summary

Instance Attribute Summary

Instance Method Summary

Pollable - Included

#polling_loop

Track the progress of the connection, waiting for the socket to become readable/writable before polling it.

Constructor Details

.new ⇒ conn .new(connection_hash) ⇒ conn .new(connection_string) ⇒ conn .new(host, port, options, tty, dbname, user, password) ⇒ conn
Also known as: .async_connect, .connect, .open, .setdb, .setdblogin

Create a connection to the specified server.

connection_hash must be a ruby Hash with connection parameters. See the list of valid parameters in the PostgreSQL documentation.

There are two accepted formats for connection_string: plain keyword = value strings and URIs. See the documentation of connection strings.

The positional parameter form has the same functionality except that the missing parameters will always take on default values. The parameters are:

host

server hostname

port

server port number

options

backend options

tty

(ignored in all versions of PostgreSQL)

dbname

connecting database name

user

login user name

password

login password

Examples:

# Connect using all defaults
PG::Connection.new

# As a Hash
PG::Connection.new( dbname: 'test', port: 5432 )

# As a String
PG::Connection.new( "dbname=test port=5432" )

# As an Array
PG::Connection.new( nil, 5432, nil, nil, 'test', nil, nil )

# As an URI
PG::Connection.new( "postgresql://user:pass@pgsql.example.com:5432/testdb?sslmode=require" )

If the Ruby default internal encoding is set (i.e., Encoding.default_internal != nil), the connection will have its client_encoding set accordingly.

Raises a Error if the connection fails.

[ GitHub ] 

  


# File 'lib/pg/connection.rb', line 803



def new(*args)
	conn = connect_to_hosts(*args)

	if block_given?
		begin
			return yield conn
		ensure
			conn.finish
		end
	end
	conn
end


  







Class Attribute Details



  

    .async_api=(enable)   (writeonly)
  



  

    

Switch between sync and async libpq API.



PG::Connection.async_api = true



this is the default. It sets an alias from #exec to #async_exec, #reset to #async_reset and so on.



PG::Connection.async_api = false



sets an alias from #exec to #sync_exec, #reset to #sync_reset and so on.



pg-1.1.0+ defaults to libpq’s async API for query related blocking methods. pg-1.3.0+ defaults to libpq’s async API for all possibly blocking methods.



PLEASE NOTE: This method is not part of the public API and is for debug and development use only. Do not use this method in production code. Any issues with the default setting of async_api=true should be reported to the maintainers instead.


  



  [ GitHub ]


  

  


# File 'lib/pg/connection.rb', line 1013



def async_api=(enable)
	self.async_send_api = enable
	REDIRECT_METHODS.each do |ali, (async, sync)|
		remove_method(ali) if method_defined?(ali)
		alias_method( ali, enable ? async : sync )
	end
	REDIRECT_CLASS_METHODS.each do |ali, (async, sync)|
		singleton_class.remove_method(ali) if method_defined?(ali)
		singleton_class.alias_method(ali, enable ? async : sync )
	end
end


  








  

    .async_send_api=(enable)   (writeonly)
  

  [ GitHub ]


  

  


# File 'lib/pg/connection.rb', line 990



def async_send_api=(enable)
	REDIRECT_SEND_METHODS.each do |ali, (async, sync)|
		undef_method(ali) if method_defined?(ali)
		alias_method( ali, enable ? async : sync )
	end
end


  







Class Method Details



  

    .async_connect(*args)  
  



  

    

Alias for .new.


  



  [ GitHub ]


  

  


# File 'lib/pg/connection.rb', line 815



alias async_connect new


  








  

    .async_ping(*args)  
  



  

    

Alias for .ping.


  



  [ GitHub ]


  

  


# File 'lib/pg/connection.rb', line 927



alias async_ping ping


  








  

    .conndefaults  ⇒ Array   



  

    

Returns an array of hashes. Each hash has the keys:


:keyword



the name of the option


:envvar



the environment variable to fall back to


:compiled



the compiled in option as a secondary fallback


:val



the option’s current value, or nil if not known


:label



the label for the field


:dispchar



“” for normal, “D” for debug, and “*” for password


:dispsize



field size




  



  [ GitHub ]


  

  


# File 'ext/pg_connection.c', line 379



static VALUE
pgconn_s_conndefaults(VALUE self)
{
	PQconninfoOption *options = PQconndefaults();
	VALUE array = pgconn_make_conninfo_array( options );

	PQconninfoFree(options);

	UNUSED( self );

	return array;
}


  








  

    .conndefaults_hash  
  



  

    

Return the Postgres connection defaults structure as a Hash keyed by option keyword (as a Symbol).



See also #conndefaults


  



  [ GitHub ]


  

  


# File 'lib/pg/connection.rb', line 337



def self.conndefaults_hash
	return self.conndefaults.each_with_object({}) do |info, hash|
		hash[ info[:keyword].to_sym ] = info[:val]
	end
end


  








  

    .connect(*args)  
  



  

    

Alias for .new.


  



  [ GitHub ]


  

  


# File 'lib/pg/connection.rb', line 816



alias connect new


  








  

    .connect_hash_to_string(hash)  
  



  

    

Convert Hash options to connection String



Values are properly quoted and escaped.


  



  [ GitHub ]


  

  


# File 'lib/pg/connection.rb', line 44



def self.connect_hash_to_string( hash )
	hash.map { |k,v| "#{k}=#{quote_connstr(v)}" }.join( ' ' )
end


  








  

    

      .connect_start(connection_hash)  ⇒ conn 
      .connect_start(connection_string)  ⇒ conn 
      .connect_start(host, port, options, tty, dbname, login, password)  ⇒ conn 
    

  



  

    

This is an asynchronous version of .new.



Use #connect_poll to poll the status of the connection.



NOTE: this does not set the connection’s client_encoding for you if Encoding.default_internal is set. To set it after the connection is established, call #internal_encoding=. You can also set it automatically by setting ENV['PGCLIENTENCODING'], or include the ‘options’ connection parameter.



See also the ‘sample’ directory of this gem and the corresponding libpq functions.


  





  


  [ GitHub ]


  

  


# File 'ext/pg_connection.c', line 316



static VALUE
pgconn_s_connect_start( int argc, VALUE *argv, VALUE klass )
{
	VALUE rb_conn;
	VALUE conninfo;
	t_pg_connection *this;

	/*
	 * PG::Connection.connect_start must act as both alloc() and initialize()
	 * because it is not invoked by calling new().
	 */
	rb_conn  = pgconn_s_allocate( klass );
	this = pg_get_connection( rb_conn );
	conninfo = rb_funcall2( klass, rb_intern("parse_connect_args"), argc, argv );
	this->pgconn = gvl_PQconnectStart( StringValueCStr(conninfo) );

	if( this->pgconn == NULL )
		rb_raise(rb_ePGerror, "PQconnectStart() unable to allocate PGconn structure");

	if ( PQstatus(this->pgconn) == CONNECTION_BAD )
		pg_raise_conn_error( rb_eConnectionBad, rb_conn, "%s", PQerrorMessage(this->pgconn));

	if ( rb_block_given_p() ) {
		return rb_ensure( rb_yield, rb_conn, pgconn_finish, rb_conn );
	}
	return rb_conn;
}


  








  

    .connect_to_hosts(*args)  
  



  

    
  





  
Raises:





  [ GitHub ]


  

  


# File 'lib/pg/connection.rb', line 855



private def connect_to_hosts(*args)
	option_string = parse_connect_args(*args)
	iopts = PG::Connection.conninfo_parse(option_string).each_with_object({}){|h, o| o[h[:keyword].to_sym] = h[:val] if h[:val] }
	iopts = PG::Connection.conndefaults.each_with_object({}){|h, o| o[h[:keyword].to_sym] = h[:val] if h[:val] }.merge(iopts)

	if PG::BUNDLED_LIBPQ_WITH_UNIXSOCKET && iopts[:host].to_s.empty?
		# Many distors patch the hardcoded default UnixSocket path in libpq to /var/run/postgresql instead of /tmp .
		# We simply try them all.
		iopts[:host] = "/var/run/postgresql" + # Ubuntu, Debian, Fedora, Opensuse
			",/run/postgresql" + # Alpine, Archlinux, Gentoo
			",/tmp" # Stock PostgreSQL
	end

	iopts_for_reset = iopts
	if iopts[:hostaddr]
		# hostaddr is provided -> no need to resolve hostnames

	elsif iopts[:host] && !iopts[:host].empty? && PG.library_version >= 100000
		iopts = resolve_hosts(iopts)
	else
		# No host given
	end
	conn = self.connect_start(iopts) or
								raise(PG::Error, "Unable to create a new connection")

	raise PG::ConnectionBad, conn.error_message if conn.status == PG::CONNECTION_BAD

	# save the connection options for conn.reset
	conn.instance_variable_set(:@iopts_for_reset, iopts_for_reset)
	conn.send(:async_connect_or_reset, :connect_poll)
	conn
end


  








  

    .conninfo_parse(conninfo_string)  ⇒ Array   



  

    

Returns parsed connection options from the provided connection string as an array of hashes. Each hash has the same keys as Connection.conndefaults() . The values from the conninfo_string are stored in the :val key.


  



  [ GitHub ]


  

  


# File 'ext/pg_connection.c', line 402



static VALUE
pgconn_s_conninfo_parse(VALUE self, VALUE conninfo)
{
	VALUE array;
	char *errmsg = NULL;
	PQconninfoOption *options = PQconninfoParse(StringValueCStr(conninfo), &errmsg);
	if(errmsg){
		VALUE error = rb_str_new_cstr(errmsg);
		PQfreemem(errmsg);
		rb_raise(rb_ePGerror, "%"PRIsVALUE, error);
	}
	array = pgconn_make_conninfo_array( options );

	PQconninfoFree(options);

	UNUSED( self );

	return array;
}


  








  

    .encrypt_password(password, username)  ⇒ String   



  

    

This is an older, deprecated version of #encrypt_password. The difference is that this function always uses md5 as the encryption algorithm.


  



  [ GitHub ]


  

  


# File 'ext/pg_connection.c', line 456



static VALUE
pgconn_s_encrypt_password(VALUE self, VALUE password, VALUE username)
{
	char *encrypted = NULL;
	VALUE rval = Qnil;

	UNUSED( self );

	Check_Type(password, T_STRING);
	Check_Type(username, T_STRING);

	encrypted = PQencryptPassword(StringValueCStr(password), StringValueCStr(username));
	rval = rb_str_new2( encrypted );
	PQfreemem( encrypted );

	return rval;
}


  








  

    .escape(str)  ⇒ String     Also known as: .escape_string, #escape_string
  



  

    

Returns a SQL-safe version of the String str. This is the preferred way to make strings safe for inclusion in SQL queries.



Consider using exec_params, which avoids the need for passing values inside of SQL commands.



Character encoding of escaped string will be equal to client encoding of connection.



NOTE: This class version of this method can only be used safely in client programs that use a single PostgreSQL connection at a time (in this case it can find out what it needs to know “behind the scenes”). It might give the wrong results if used in programs that use multiple database connections; use the same method on the connection object in such cases.



See also convenience functions #escape_literal and #escape_identifier which also add proper quotes around the string.


  



  [ GitHub ]


  

  


# File 'ext/pg_connection.c', line 1657



static VALUE
pgconn_s_escape(VALUE self, VALUE string)
{
	size_t size;
	int error;
	VALUE result;
	int enc_idx;
	int singleton = !rb_obj_is_kind_of(self, rb_cPGconn);

	StringValueCStr(string);
	enc_idx = singleton ? ENCODING_GET(string) : pg_get_connection(self)->enc_idx;
	if( ENCODING_GET(string) != enc_idx ){
		string = rb_str_export_to_enc(string, rb_enc_from_index(enc_idx));
	}

	result = rb_str_new(NULL, RSTRING_LEN(string) * 2 + 1);
	PG_ENCODING_SET_NOCHECK(result, enc_idx);
	if( !singleton ) {
		size = PQescapeStringConn(pg_get_pgconn(self), RSTRING_PTR(result),
			RSTRING_PTR(string), RSTRING_LEN(string), &error);
		if(error)
			pg_raise_conn_error( rb_ePGerror, self, "%s", PQerrorMessage(pg_get_pgconn(self)));

	} else {
		size = PQescapeString(RSTRING_PTR(result), RSTRING_PTR(string), RSTRING_LEN(string));
	}
	rb_str_set_len(result, size);

	return result;
}


  








  

    #escape_bytea(string)  ⇒ String     Also known as: #escape_bytea
  



  

    

Escapes binary data for use within an SQL command with the type bytea.



Certain byte values must be escaped (but all byte values may be escaped) when used as part of a bytea literal in an SQL statement. In general, to escape a byte, it is converted into the three digit octal number equal to the octet value, and preceded by two backslashes. The single quote (‘) and backslash () characters have special alternative escape sequences. #escape_bytea performs this operation, escaping only the minimally required bytes.



Consider using exec_params, which avoids the need for passing values inside of SQL commands.



NOTE: This class version of this method can only be used safely in client programs that use a single PostgreSQL connection at a time (in this case it can find out what it needs to know “behind the scenes”). It might give the wrong results if used in programs that use multiple database connections; use the same method on the connection object in such cases.


  



  [ GitHub ]


  

  


# File 'ext/pg_connection.c', line 1711



static VALUE
pgconn_s_escape_bytea(VALUE self, VALUE str)
{
	unsigned char *from, *to;
	size_t from_len, to_len;
	VALUE ret;

	Check_Type(str, T_STRING);
	from      = (unsigned char*)RSTRING_PTR(str);
	from_len  = RSTRING_LEN(str);

	if ( rb_obj_is_kind_of(self, rb_cPGconn) ) {
		to = PQescapeByteaConn(pg_get_pgconn(self), from, from_len, &to_len);
	} else {
		to = PQescapeBytea( from, from_len, &to_len);
	}

	ret = rb_str_new((char*)to, to_len - 1);
	PQfreemem(to);
	return ret;
}


  








  

    

      #escape(str)  ⇒ String 
      .escape_string(str)  ⇒ String 
    

  



  

    

Alias for .escape.


  





  








  

    .host_is_named_pipe?(host_string)  ⇒ Boolean 
  



  

    
  





  


  [ GitHub ]


  

  


# File 'lib/pg/connection.rb', line 888



private def host_is_named_pipe?(host_string)
	host_string.empty? || host_string.start_with?("/") ||  # it's UnixSocket?
					host_string.start_with?("@") ||  # it's UnixSocket in the abstract namespace?
					# it's a path on Windows?
					(RUBY_PLATFORM =~ /mingw|mswin/ && host_string =~ /\A([\/\\]|\w:[\/\\])/)
end


  








  

    .open(*args)  
  



  

    

Alias for .new.


  



  [ GitHub ]


  

  


# File 'lib/pg/connection.rb', line 817



alias open new


  








  

    .parse_connect_args(*args)  
  



  

    

Parse the connection args into a connection-parameter string. See .new for valid arguments.



It accepts:


  • 

    an option String kind of “host=name port=5432”
    

  • 

    an option Hash kind of “name”, port: 5432
    

  • 

    URI string
    

  • 

    URI object
    

  • 

    positional arguments
    




The method adds the option “fallback_application_name” if it isn’t already set. It returns a connection string with “key=value” pairs.


  



  [ GitHub ]


  

  


# File 'lib/pg/connection.rb', line 64



def self.parse_connect_args( *args )
	hash_arg = args.last.is_a?( Hash ) ? args.pop.transform_keys(&:to_sym) : {}
	iopts = {}

	if args.length == 1
		case args.first.to_s
		when /=/, /:\/\//
			# Option or URL string style
			conn_string = args.first.to_s
			iopts = PG::Connection.conninfo_parse(conn_string).each_with_object({}){|h, o| o[h[:keyword].to_sym] = h[:val] if h[:val] }
		else
			# Positional parameters (only host given)
			iopts[CONNECT_ARGUMENT_ORDER.first.to_sym] = args.first
		end
	else
		# Positional parameters with host and more
		max = CONNECT_ARGUMENT_ORDER.length
		raise ArgumentError,
				"Extra positional parameter %d: %p" % [ max + 1, args[max] ] if args.length > max

		CONNECT_ARGUMENT_ORDER.zip( args ) do |(k,v)|
			iopts[ k.to_sym ] = v if v
		end
		iopts.delete(:tty) # ignore obsolete tty parameter
	end

	iopts.merge!( hash_arg )

	if !iopts[:fallback_application_name]
		iopts[:fallback_application_name] = PROGRAM_NAME.sub( /^(.{30}).{4,}(.{30})$/ ){ $1"..."$2 }
	end

	return connect_hash_to_string(iopts)
end


  








  

    

      .ping(connection_hash)  ⇒ Integer 
      .ping(connection_string)  ⇒ Integer 
      .ping(host, port, options, tty, dbname, login, password)  ⇒ Integer 
    

    Also known as: .async_ping
  



  

    

PQpingParams reports the status of the server.



It accepts connection parameters identical to those of PQ::Connection.new . It is not necessary to supply correct user name, password, or database name values to obtain the server status; however, if incorrect values are provided, the server will log a failed connection attempt.



See .new for a description of the parameters.



Returns one of:


PQPING_OK



server is accepting connections


PQPING_REJECT



server is alive but rejecting connections


PQPING_NO_RESPONSE



could not establish connection


PQPING_NO_ATTEMPT



connection not attempted (bad params)





See also check_socket for a way to check the connection without doing any server communication.


  





  


  [ GitHub ]


  

  


# File 'lib/pg/connection.rb', line 918



def ping(*args)
	if Fiber.respond_to?(:scheduler) && Fiber.scheduler
		# Run PQping in a second thread to avoid blocking of the scheduler.
		# Unfortunately there's no nonblocking way to run ping.
		Thread.new { sync_ping(*args) }.value
	else
		sync_ping(*args)
	end
end


  








  

    .quote_connstr(value)  
  



  

    

Quote a single value for use in a connection-parameter string.


  



  [ GitHub ]


  

  


# File 'lib/pg/connection.rb', line 37



def self.quote_connstr( value )
	return "'" + value.to_s.gsub( /[\\']/ ) {|m| '\\' + m } + "'"
end


  








  

    

      #quote_ident(str)  ⇒ String 
      #quote_ident(array)  ⇒ String 
      #quote_ident(str)  ⇒ String 
      #quote_ident(array)  ⇒ String 
    

    Also known as: #quote_ident
  



  

    

Returns a string that is safe for inclusion in a SQL query as an identifier. Note: this is not a quote function for values, but for identifiers.



For example, in a typical SQL query: SELECT FOO FROM MYTABLE The identifier FOO is folded to lower case, so it actually means foo. If you really want to access the case-sensitive field name FOO, use this function like conn.quote_ident('FOO'), which will return "FOO" (with double-quotes). PostgreSQL will see the double-quotes, and it will not fold to lower case.



Similarly, this function also protects against special characters, and other things that might allow SQL injection if the identifier comes from an untrusted source.



If the parameter is an Array, then all it’s values are separately quoted and then joined by a “.” character. This can be used for identifiers in the form “schema”.“table”.“column” .



This method is functional identical to the encoder TextEncoder::Identifier .



If the instance method form is used and the input string character encoding is different to the connection encoding, then the string is converted to this encoding, so that the returned string is always encoded as #internal_encoding .



In the singleton form (PG::Connection.quote_ident) the character encoding of the result string is set to the character encoding of the input string.


  





  


  [ GitHub ]


  

  


# File 'ext/pg_connection.c', line 3120



static VALUE
pgconn_s_quote_ident(VALUE self, VALUE str_or_array)
{
	VALUE ret;
	int enc_idx;

	if( rb_obj_is_kind_of(self, rb_cPGconn) ){
		enc_idx = pg_get_connection(self)->enc_idx;
	}else{
		enc_idx = RB_TYPE_P(str_or_array, T_STRING) ? ENCODING_GET( str_or_array ) : rb_ascii8bit_encindex();
	}
	pg_text_enc_identifier(NULL, str_or_array, NULL, &ret, enc_idx);

	return ret;
}


  








  

    .resolve_hosts(iopts)  
  



  

    
  





  
Raises:





  [ GitHub ]


  

  


# File 'lib/pg/connection.rb', line 824



private def resolve_hosts(iopts)
	ihosts = iopts[:host].split(",", -1)
	iports = iopts[:port].split(",", -1)
	iports = [nil] if iports.size == 0
	iports = iports * ihosts.size if iports.size == 1
	raise PG::ConnectionBad, "could not match #{iports.size} port numbers to #{ihosts.size} hosts" if iports.size != ihosts.size

	dests = ihosts.each_with_index.flat_map do |mhost, idx|
		unless host_is_named_pipe?(mhost)
			if Fiber.respond_to?(:scheduler) &&
						Fiber.scheduler &&
						RUBY_VERSION < '3.1.'

				# Use a second thread to avoid blocking of the scheduler.
				# `TCPSocket.gethostbyname` isn't fiber aware before ruby-3.1.
				hostaddrs = Thread.new{ Addrinfo.getaddrinfo(mhost, nil, nil, :STREAM).map(&:ip_address) rescue [''] }.value
			else
				hostaddrs = Addrinfo.getaddrinfo(mhost, nil, nil, :STREAM).map(&:ip_address) rescue ['']
			end
		else
			# No hostname to resolve (UnixSocket)
			hostaddrs = [nil]
		end
		hostaddrs.map { |hostaddr| [hostaddr, mhost, iports[idx]] }
	end
	iopts.merge(
		hostaddr: dests.map{|d| d[0] }.join(","),
		host: dests.map{|d| d[1] }.join(","),
		port: dests.map{|d| d[2] }.join(","))
end


  








  

    .setdb(*args)  
  



  

    

Alias for .new.


  



  [ GitHub ]


  

  


# File 'lib/pg/connection.rb', line 818



alias setdb new


  








  

    .setdblogin(*args)  
  



  

    

Alias for .new.


  



  [ GitHub ]


  

  


# File 'lib/pg/connection.rb', line 819



alias setdblogin new


  








  

    .sync_connect(*args)  
  

  [ GitHub ]


  

  


# File 'ext/pg_connection.c', line 273



static VALUE
pgconn_s_sync_connect(int argc, VALUE *argv, VALUE klass)
{
	t_pg_connection *this;
	VALUE conninfo;
	VALUE self = pgconn_s_allocate( klass );

	this = pg_get_connection( self );
	conninfo = rb_funcall2( rb_cPGconn, rb_intern("parse_connect_args"), argc, argv );
	this->pgconn = gvl_PQconnectdb(StringValueCStr(conninfo));

	if(this->pgconn == NULL)
		rb_raise(rb_ePGerror, "PQconnectdb() unable to allocate PGconn structure");

	if (PQstatus(this->pgconn) == CONNECTION_BAD)
		pg_raise_conn_error( rb_eConnectionBad, self, "%s", PQerrorMessage(this->pgconn));

	pgconn_set_default_encoding( self );

	if (rb_block_given_p()) {
		return rb_ensure(rb_yield, self, pgconn_finish, self);
	}
	return self;
}


  








  

    .sync_ping(*args)  
  

  [ GitHub ]


  

  


# File 'ext/pg_connection.c', line 344



static VALUE
pgconn_s_sync_ping( int argc, VALUE *argv, VALUE klass )
{
	PGPing ping;
	VALUE conninfo;

	conninfo = rb_funcall2( klass, rb_intern("parse_connect_args"), argc, argv );
	ping     = gvl_PQping( StringValueCStr(conninfo) );

	return INT2FIX((int)ping);
}


  








  

    #unescape_bytea(string)      Also known as: #unescape_bytea
  



  

    

Converts an escaped string representation of binary data into binary data — the reverse of #escape_bytea. This is needed when retrieving bytea data in text format, but not when retrieving it in binary format.


  



  [ GitHub ]


  

  


# File 'ext/pg_connection.c', line 1743



static VALUE
pgconn_s_unescape_bytea(VALUE self, VALUE str)
{
	unsigned char *from, *to;
	size_t to_len;
	VALUE ret;

	UNUSED( self );

	Check_Type(str, T_STRING);
	from = (unsigned char*)StringValueCStr(str);

	to = PQunescapeBytea(from, &to_len);

	ret = rb_str_new((char*)to, to_len);
	PQfreemem(to);
	return ret;
}


  







Instance Attribute Details



  

    #decoder_for_get_copy_data  ⇒ PG::Coder  (rw)  



  

    

Returns the default coder object that is currently set for type casting of received data by #get_copy_data .



Returns either:


  • 

    a kind of Coder
    

  • 

    nil - type encoding is disabled, returned data will be a String.
    



  



  [ GitHub ]


  

  


# File 'ext/pg_connection.c', line 4572



static VALUE
pgconn_decoder_for_get_copy_data_get(VALUE self)
{
	t_pg_connection *this = pg_get_connection( self );

	return this->decoder_for_get_copy_data;
}


  








  

    #decoder_for_get_copy_data=(decoder)   (rw)  



  

    

Set the default coder that is used for type casting of received data by #get_copy_data .



decoder can be:


  • 

    a kind of Coder
    

  • 

    nil - disable type decoding, returned data will be a String.
    



  



  [ GitHub ]


  

  


# File 'ext/pg_connection.c', line 4543



static VALUE
pgconn_decoder_for_get_copy_data_set(VALUE self, VALUE decoder)
{
	t_pg_connection *this = pg_get_connection( self );

	rb_check_frozen(self);
	if( decoder != Qnil ){
		t_pg_coder *co;
		UNUSED(co);
		/* Check argument type */
		TypedData_Get_Struct(decoder, t_pg_coder, &pg_coder_type, co);
	}
	RB_OBJ_WRITE(self, &this->decoder_for_get_copy_data, decoder);

	return decoder;
}


  








  

    #encoder_for_put_copy_data  ⇒ PG::Coder  (rw)  



  

    

Returns the default coder object that is currently set for type casting of parameters to #put_copy_data .



Returns either:


  • 

    a kind of Coder
    

  • 

    nil - type encoding is disabled, data must be a String.
    



  



  [ GitHub ]


  

  


# File 'ext/pg_connection.c', line 4523



static VALUE
pgconn_encoder_for_put_copy_data_get(VALUE self)
{
	t_pg_connection *this = pg_get_connection( self );

	return this->encoder_for_put_copy_data;
}


  








  

    #encoder_for_put_copy_data=(encoder)   (rw)  



  

    

Set the default coder that is used for type casting of parameters to #put_copy_data .



encoder can be:


  • 

    a kind of Coder
    

  • 

    nil - disable type encoding, data must be a String.
    



  



  [ GitHub ]


  

  


# File 'ext/pg_connection.c', line 4494



static VALUE
pgconn_encoder_for_put_copy_data_set(VALUE self, VALUE encoder)
{
	t_pg_connection *this = pg_get_connection( self );

	rb_check_frozen(self);
	if( encoder != Qnil ){
		t_pg_coder *co;
		UNUSED(co);
		/* Check argument type */
		TypedData_Get_Struct(encoder, t_pg_coder, &pg_coder_type, co);
	}
	RB_OBJ_WRITE(self, &this->encoder_for_put_copy_data, encoder);

	return encoder;
}


  








  

    #field_name_type  ⇒ Symbol  (rw)  



  

    

Get type of field names.



See description at #field_name_type=


  



  [ GitHub ]


  

  


# File 'ext/pg_connection.c', line 4619



static VALUE
pgconn_field_name_type_get(VALUE self)
{
	t_pg_connection *this = pg_get_connection( self );

	if( this->flags & PG_RESULT_FIELD_NAMES_SYMBOL ){
		return sym_symbol;
	} else if( this->flags & PG_RESULT_FIELD_NAMES_STATIC_SYMBOL ){
		return sym_static_symbol;
	} else {
		return sym_string;
	}
}


  








  

    #field_name_type=(Symbol)   (rw)  



  

    

Set default type of field names of results retrieved by this connection. It can be set to one of:


  • 

    :string to use String based field names
    

  • 

    :symbol to use Symbol based field names
    




The default is :string .



Settings the type of field names affects only future results.



See further description at Result#field_name_type=


  



  [ GitHub ]


  

  


# File 'ext/pg_connection.c', line 4596



static VALUE
pgconn_field_name_type_set(VALUE self, VALUE sym)
{
	t_pg_connection *this = pg_get_connection( self );

	rb_check_frozen(self);
	this->flags &= ~PG_RESULT_FIELD_NAMES_MASK;
	if( sym == sym_symbol ) this->flags |= PG_RESULT_FIELD_NAMES_SYMBOL;
	else if ( sym == sym_static_symbol ) this->flags |= PG_RESULT_FIELD_NAMES_STATIC_SYMBOL;
	else if ( sym == sym_string );
	else rb_raise(rb_eArgError, "invalid argument %+"PRIsVALUE, sym);

	return sym;
}


  








  

    #finished?  ⇒ Boolean  (readonly)  



  

    

Returns true if the backend connection has been closed.


  



  [ GitHub ]


  

  


# File 'ext/pg_connection.c', line 549



static VALUE
pgconn_finished_p( VALUE self )
{
	t_pg_connection *this = pg_get_connection( self );
	if ( this->pgconn ) return Qfalse;
	return Qtrue;
}


  








  

    #flush_data=(enabled)   (writeonly, private)
  

  [ GitHub ]


  

  


# File 'ext/pg_connection.c', line 2606



static VALUE
pgconn_flush_data_set( VALUE self, VALUE enabled ){
	t_pg_connection *conn = pg_get_connection(self);
	rb_check_frozen(self);
	conn->flush_data = RTEST(enabled);
	return enabled;
}


  








  

    #internal_encoding  ⇒ Encoding  (rw)  



  

    

defined in Ruby 1.9 or later.



Returns:


  • 

    an Encoding - client_encoding of the connection as a Ruby Encoding object.
    

  • 

    nil - the client_encoding is ‘SQL_ASCII’
    



  



  [ GitHub ]


  

  


# File 'ext/pg_connection.c', line 4243



static VALUE
pgconn_internal_encoding(VALUE self)
{
	PGconn *conn = pg_get_pgconn( self );
	rb_encoding *enc = pg_conn_enc_get( conn );

	if ( enc ) {
		return rb_enc_from_encoding( enc );
	} else {
		return Qnil;
	}
}


  








  

    #internal_encoding=(value)   (rw)  



  

    

A wrapper of #set_client_encoding. defined in Ruby 1.9 or later.



value can be one of:


  • 

    an Encoding
    

  • 

    a String - a name of Encoding
    

  • 

    nil - sets the client_encoding to SQL_ASCII.
    



  



  [ GitHub ]


  

  


# File 'ext/pg_connection.c', line 4270



static VALUE
pgconn_internal_encoding_set(VALUE self, VALUE enc)
{
	rb_check_frozen(self);
	if (NIL_P(enc)) {
		pgconn_sync_set_client_encoding( self, rb_usascii_str_new_cstr("SQL_ASCII") );
		return enc;
	}
	else if ( TYPE(enc) == T_STRING && strcasecmp("JOHAB", StringValueCStr(enc)) == 0 ) {
		pgconn_sync_set_client_encoding(self, rb_usascii_str_new_cstr("JOHAB"));
		return enc;
	}
	else {
		rb_encoding *rbenc = rb_to_encoding( enc );
		const char *name = pg_get_rb_encoding_as_pg_encoding( rbenc );

		if ( gvl_PQsetClientEncoding(pg_get_pgconn( self ), name) == -1 ) {
			VALUE server_encoding = pgconn_external_encoding( self );
			rb_raise( rb_eEncCompatError, "incompatible character encodings: %s and %s",
					  rb_enc_name(rb_to_encoding(server_encoding)), name );
		}
		pgconn_set_internal_encoding_index( self );
		return enc;
	}
}


  








  

    #nonblocking?   (readonly)
  



  

    

Alias for #isnonblocking.


  



  [ GitHub ]


  

  


# File 'lib/pg/connection.rb', line 480



alias nonblocking? isnonblocking


  








  

    #ssl_in_use?  ⇒ Boolean  (readonly)  



  

    

Returns true if the connection uses SSL/TLS, false if not.


  



  [ GitHub ]


  

  


# File 'ext/pg_connection.c', line 3669



static VALUE
pgconn_ssl_in_use(VALUE self)
{
	return PQsslInUse(pg_get_pgconn(self)) ? Qtrue : Qfalse;
}


  








  

    #type_map_for_queries  ⇒ TypeMap  (rw)  



  

    

Returns the default TypeMap that is currently set for type casts of query bind parameters.


  



  [ GitHub ]


  

  


# File 'ext/pg_connection.c', line 4435



static VALUE
pgconn_type_map_for_queries_get(VALUE self)
{
	t_pg_connection *this = pg_get_connection( self );

	return this->type_map_for_queries;
}


  








  

    #type_map_for_queries=(typemap)   (rw)  



  

    

Set the default TypeMap that is used for type casts of query bind parameters.



typemap must be a kind of TypeMap .


  



  [ GitHub ]


  

  


# File 'ext/pg_connection.c', line 4411



static VALUE
pgconn_type_map_for_queries_set(VALUE self, VALUE typemap)
{
	t_pg_connection *this = pg_get_connection( self );
	t_typemap *tm;
	UNUSED(tm);

	rb_check_frozen(self);
	/* Check type of method param */
	TypedData_Get_Struct(typemap, t_typemap, &pg_typemap_type, tm);

	RB_OBJ_WRITE(self, &this->type_map_for_queries, typemap);

	return typemap;
}


  








  

    #type_map_for_results  ⇒ TypeMap  (rw)  



  

    

Returns the default TypeMap that is currently set for type casts of result values.


  



  [ GitHub ]


  

  


# File 'ext/pg_connection.c', line 4473



static VALUE
pgconn_type_map_for_results_get(VALUE self)
{
	t_pg_connection *this = pg_get_connection( self );

	return this->type_map_for_results;
}


  








  

    #type_map_for_results=(typemap)   (rw)  



  

    

Set the default TypeMap that is used for type casts of result values.



typemap must be a kind of TypeMap .


  



  [ GitHub ]


  

  


# File 'ext/pg_connection.c', line 4452



static VALUE
pgconn_type_map_for_results_set(VALUE self, VALUE typemap)
{
	t_pg_connection *this = pg_get_connection( self );
	t_typemap *tm;
	UNUSED(tm);

	rb_check_frozen(self);
	TypedData_Get_Struct(typemap, t_typemap, &pg_typemap_type, tm);
	RB_OBJ_WRITE(self, &this->type_map_for_results, typemap);

	return typemap;
}


  







Instance Method Details



  

    #async_cancel  
  



  

    

Alias for #cancel.


  



  [ GitHub ]


  

  


# File 'lib/pg/connection.rb', line 674



alias async_cancel cancel


  








  

    

      #close_portal(portal_name)  ⇒ PG::Result 
      #async_close_portal(portal_name)  ⇒ PG::Result 
    

  



  

    

Alias for #close_portal.


  









  

    

      #close_prepared(statement_name)  ⇒ PG::Result 
      #async_close_prepared(statement_name)  ⇒ PG::Result 
    

  



  

    

Alias for #close_prepared.


  









  

    #async_connect_or_reset(poll_meth)   (private)
  

  [ GitHub ]


  

  


# File 'lib/pg/connection.rb', line 740



private def async_connect_or_reset(poll_meth)
	# Track the progress of the connection, waiting for the socket to become readable/writable before polling it
	polling_loop(poll_meth, conninfo_hash[:connect_timeout])

	# Set connection to nonblocking to handle all blocking states in ruby.
	# That way a fiber scheduler is able to handle IO requests.
	sync_setnonblocking(true)
	self.flush_data = true
	set_default_encoding
end


  








  

    

      #describe_portal(portal_name)  ⇒ PG::Result 
      #async_describe_portal(portal_name)  ⇒ PG::Result 
    

  



  

    

Alias for #describe_portal.


  









  

    

      #describe_prepared(statement_name)  ⇒ PG::Result 
      #async_describe_prepared(statement_name)  ⇒ PG::Result 
    

  



  

    

Alias for #describe_prepared.


  









  

    #async_encrypt_password(password, username, algorithm = nil)  
  



  

    

Alias for #encrypt_password.


  



  [ GitHub ]


  

  


# File 'lib/pg/connection.rb', line 583



alias async_encrypt_password encrypt_password


  








  

    

      #exec(sql)  ⇒ PG::Result 
      #exec(sql) {|pg_result| ... } 
    

    Also known as: #async_query
  



  

    

Alias for #exec.


  









  

    

      #exec_params(sql, params [, result_format [, type_map ]] )  ⇒ nil 
      #exec_params(sql, params [, result_format [, type_map ]] ) {|pg_result| ... } 
    

  



  

    

Alias for #exec_params.


  









  

    

      #exec_prepared(statement_name [, params, result_format[, type_map]] )  ⇒ PG::Result 
      #exec_prepared(statement_name [, params, result_format[, type_map]] ) {|pg_result| ... } 
    

  



  

    

Alias for #exec_prepared.


  









  

    

      #flush  ⇒ Boolean 
      #async_flush  ⇒ Boolean 
    

  



  

    

Alias for #flush.


  









  

    #async_get_copy_data(async = false, decoder = nil)  
  



  

    

Alias for #get_copy_data.


  



  [ GitHub ]


  

  


# File 'lib/pg/connection.rb', line 439



alias async_get_copy_data get_copy_data


  








  

    

      #get_last_result()  ⇒ PG::Result 
      #async_get_last_result()  ⇒ PG::Result 
    

  



  

    

Alias for #get_last_result.


  









  

    #async_get_result  
  



  

    

Alias for #get_result.


  



  [ GitHub ]


  

  


# File 'lib/pg/connection.rb', line 409



alias async_get_result get_result


  








  

    #async_isnonblocking  
  



  

    

Alias for #isnonblocking.


  



  [ GitHub ]


  

  


# File 'lib/pg/connection.rb', line 479



alias async_isnonblocking isnonblocking


  








  

    #async_pipeline_sync(*args)  
  



  

    

Alias for #pipeline_sync.


  



  [ GitHub ]


  

  


# File 'lib/pg/connection.rb', line 555



alias async_pipeline_sync pipeline_sync


  








  

    

      #prepare(stmt_name, sql [, param_types ] )  ⇒ PG::Result 
      #async_prepare(stmt_name, sql [, param_types ] )  ⇒ PG::Result 
    

  



  

    

Alias for #prepare.


  









  

    #async_put_copy_data(buffer, encoder = nil)  
  



  

    

Alias for #put_copy_data.


  



  [ GitHub ]


  

  


# File 'lib/pg/connection.rb', line 516



alias async_put_copy_data put_copy_data


  








  

    #async_put_copy_end(*args)  
  



  

    

Alias for #put_copy_end.


  



  [ GitHub ]


  

  


# File 'lib/pg/connection.rb', line 537



alias async_put_copy_end put_copy_end


  








  

    

      #exec(sql)  ⇒ PG::Result 
      #exec(sql) {|pg_result| ... } 
    

  



  

    

Alias for #async_exec.


  









  

    #async_reset  
  



  

    

Alias for #reset.


  



  [ GitHub ]


  

  


# File 'lib/pg/connection.rb', line 603



alias async_reset reset


  








  

    

      #client_encoding=(encoding)  
      #async_set_client_encoding(encoding)  
    

  



  

    

Alias for #client_encoding=.


  









  

    #async_setnonblocking(enabled)  
  



  

    

Alias for #setnonblocking.


  



  [ GitHub ]


  

  


# File 'lib/pg/connection.rb', line 467



alias async_setnonblocking setnonblocking


  








  

    #backend_key  
  



  

    

key of backend — needed for cancels


  



  [ GitHub ]


  

  


# File 'ext/pg_connection.c', line 1019



static VALUE
pgconn_backend_key(VALUE self)
{
	int be_key;
	struct pg_cancel *cancel;
	PGconn *conn = pg_get_pgconn(self);

	cancel = (struct pg_cancel*)PQgetCancel(conn);
	if(cancel == NULL)
		pg_raise_conn_error( rb_ePGerror, self, "Invalid connection!");

	if( cancel->be_pid != PQbackendPID(conn) )
		rb_raise(rb_ePGerror,"Unexpected binary struct layout - please file a bug report at ruby-pg!");

	be_key = cancel->be_key;

	PQfreeCancel(cancel);

	return INT2NUM(be_key);
}


  








  

    #backend_pid  ⇒ Integer   



  

    

Returns the process ID of the backend server process for this connection. Note that this is a PID on database server host.


  



  [ GitHub ]


  

  


# File 'ext/pg_connection.c', line 988



static VALUE
pgconn_backend_pid(VALUE self)
{
	return INT2NUM(PQbackendPID(pg_get_pgconn(self)));
}


  








  

    #block([ timeout ])  ⇒ Boolean   



  

    

Blocks until the server is no longer busy, or until the optional timeout is reached, whichever comes first. timeout is measured in seconds and can be fractional.



Returns false if timeout is reached, true otherwise.



If true is returned, conn.is_busy will return false and conn.get_result will not block.


  



  [ GitHub ]


  

  


# File 'ext/pg_connection.c', line 3157



VALUE
pgconn_block( int argc, VALUE *argv, VALUE self ) {
	struct timeval timeout;
	struct timeval *ptimeout = NULL;
	VALUE timeout_in;
	double timeout_sec;
	void *ret;

	if ( rb_scan_args(argc, argv, "01", &timeout_in) == 1 ) {
		timeout_sec = NUM2DBL( timeout_in );
		timeout.tv_sec = (time_t)timeout_sec;
		timeout.tv_usec = (suseconds_t)((timeout_sec - (long)timeout_sec) * 1e6);
		ptimeout = &timeout;
	}

	ret = wait_socket_readable( self, ptimeout, get_result_readable);

	if( !ret )
		return Qfalse;

	return Qtrue;
}


  








  

    #cancel  ⇒ String     Also known as: #async_cancel
  



  

    

Requests cancellation of the command currently being processed.



Returns nil on success, or a string containing the error message if a failure occurs.



On PostgreSQL-17+ client libaray the class CancelConnection is used. On older client library a pure ruby implementation is used.



See additional method definition at line 626.


  



  [ GitHub ]


  

  


# File 'lib/pg/connection.rb', line 638



def cancel
	cancon = PG::CancelConnection.new(self)
	cancon.async_connect_timeout = conninfo_hash[:connect_timeout]
	cancon.async_cancel
rescue PG::Error => err
	err.to_s
end


  








  

    #check_socket  
  



  

    

Read all pending socket input to internal memory and raise an exception in case of errors.



This verifies that the connection socket is in a usable state and not aborted in any way. No communication is done with the server. Only pending data is read from the socket - the method doesn’t wait for any outstanding server answers.



Raises a kind of Error if there was an error reading the data or if the socket is in a failure state.



The method doesn’t verify that the server is still responding. To verify that the communication to the server works, it is recommended to use something like conn.exec('') instead.


  



  [ GitHub ]


  

  


# File 'lib/pg/connection.rb', line 384



def check_socket
	while socket_io.wait_readable(0)
		consume_input
	end
	nil
end


  








  

    #client_encoding=(encoding)      Also known as: #set_client_encoding, #async_set_client_encoding
  



  

    

Sets the client encoding to the encoding String.


  



  [ GitHub ]


  

  


# File 'ext/pg_connection.c', line 4323



static VALUE
pgconn_async_set_client_encoding(VALUE self, VALUE encname)
{
	VALUE query_format, query;

	rb_check_frozen(self);
	Check_Type(encname, T_STRING);
	query_format = rb_str_new_cstr("set client_encoding to '%s'");
	query = rb_funcall(query_format, rb_intern("%"), 1, encname);

	pgconn_async_exec(1, &query, self);
	pgconn_set_internal_encoding_index( self );

	return Qnil;
}


  








  

    #close      Also known as: #finish
  



  

    

Closes the backend connection.


  



  [ GitHub ]


  

  


# File 'ext/pg_connection.c', line 531



static VALUE
pgconn_finish( VALUE self )
{
	t_pg_connection *this = pg_get_connection_safe( self );

	pgconn_close_socket_io( self );
	PQfinish( this->pgconn );
	this->pgconn = NULL;
	return Qnil;
}


  








  

    #close_portal(portal_name)  ⇒ PG::Result     Also known as: #async_close_portal
  



  

    

Submits a request to close the specified portal, and waits for completion.



close_portal allows an application to trigger a close of a previously created portal. Closing a portal releases all of its associated resources on the server and allows its name to be reused. (pg does not provide any direct access to portals, but you can use this function to close a cursor created with a DECLARE CURSOR SQL command.)



portal_name can be “” or nil to reference the unnamed portal. It is fine if no portal exists with this name, in that case the operation is a no-op. On success, a Result with status PGRES_COMMAND_OK is returned.



See also corresponding libpq function.



Available since PostgreSQL-17.


  



  [ GitHub ]


  

  


# File 'ext/pg_connection.c', line 3655



static VALUE
pgconn_async_close_portal(VALUE self, VALUE portal)
{
	return pgconn_async_describe_close_prepared_potral(self, portal, pgconn_send_close_portal);
}


  








  

    #close_prepared(statement_name)  ⇒ PG::Result     Also known as: #async_close_prepared
  



  

    

Submits a request to close the specified prepared statement, and waits for completion. close_prepared allows an application to close a previously prepared statement. Closing a statement releases all of its associated resources on the server and allows its name to be reused. It’s the same as using the DEALLOCATE SQL statement, but on a lower protocol level.



statement_name can be “” or nil to reference the unnamed statement. It is fine if no statement exists with this name, in that case the operation is a no-op. On success, a Result with status PGRES_COMMAND_OK is returned.



See also corresponding libpq function.



Available since PostgreSQL-17.


  



  [ GitHub ]


  

  


# File 'ext/pg_connection.c', line 3631



static VALUE
pgconn_async_close_prepared(VALUE self, VALUE stmt_name)
{
	return pgconn_async_describe_close_prepared_potral(self, stmt_name, pgconn_send_close_prepared);
}


  








  

    #conndefaults  
  



  

    

Returns an array of Hashes with connection defaults. See .conndefaults for details.


  



  [ GitHub ]


  

  


# File 'lib/pg/connection.rb', line 329



def conndefaults
	return self.class.conndefaults
end


  








  

    #conndefaults_hash  
  



  

    

Returns a Hash with connection defaults. See .conndefaults_hash for details.


  



  [ GitHub ]


  

  


# File 'lib/pg/connection.rb', line 345



def conndefaults_hash
	return self.class.conndefaults_hash
end


  








  

    #connect_poll  ⇒ Integer   



  

    

Returns one of:


PGRES_POLLING_READING



wait until the socket is ready to read


PGRES_POLLING_WRITING



wait until the socket is ready to write


PGRES_POLLING_FAILED



the asynchronous connection has failed


PGRES_POLLING_OK



the asynchronous connection is ready





Example:



require "io/wait"

conn = PG::Connection.connect_start(dbname: 'mydatabase')
status = conn.connect_poll
while(status != PG::PGRES_POLLING_OK) do
  # do some work while waiting for the connection to complete
  if(status == PG::PGRES_POLLING_READING)
    unless conn.socket_io.wait_readable(10.0)
      raise "Asynchronous connection timed out!"
    end
  elsif(status == PG::PGRES_POLLING_WRITING)
    unless conn.socket_io.wait_writable(10.0)
      raise "Asynchronous connection timed out!"
    end
  end
  status = conn.connect_poll
end
# now conn.status == CONNECTION_OK, and connection
# is ready.


  



  [ GitHub ]


  

  


# File 'ext/pg_connection.c', line 514



static VALUE
pgconn_connect_poll(VALUE self)
{
	PostgresPollingStatusType status;

	pgconn_close_socket_io(self);
	status = gvl_PQconnectPoll(pg_get_pgconn(self));

	return INT2FIX((int)status);
}


  








  

    #connection_needs_password  ⇒ Boolean   



  

    

Returns true if the authentication method required a password, but none was available. false otherwise.


  



  [ GitHub ]


  

  


# File 'ext/pg_connection.c', line 1048



static VALUE
pgconn_connection_needs_password(VALUE self)
{
	return PQconnectionNeedsPassword(pg_get_pgconn(self)) ? Qtrue : Qfalse;
}


  








  

    #connection_used_password  ⇒ Boolean   



  

    

Returns true if the authentication method used a caller-supplied password, false otherwise.


  



  [ GitHub ]


  

  


# File 'ext/pg_connection.c', line 1061



static VALUE
pgconn_connection_used_password(VALUE self)
{
	return PQconnectionUsedPassword(pg_get_pgconn(self)) ? Qtrue : Qfalse;
}


  








  

    #conninfo  ⇒ Hash   



  

    

Returns the connection options used by a live connection.


  



  [ GitHub ]


  

  


# File 'ext/pg_connection.c', line 763



static VALUE
pgconn_conninfo( VALUE self )
{
	PGconn *conn = pg_get_pgconn(self);
	PQconninfoOption *options = PQconninfo( conn );
	VALUE array = pgconn_make_conninfo_array( options );

	PQconninfoFree(options);

	return array;
}


  








  

    #conninfo_hash  
  



  

    

Return the Postgres connection info structure as a Hash keyed by option keyword (as a Symbol).



See also #conninfo


  



  [ GitHub ]


  

  


# File 'lib/pg/connection.rb', line 353



def conninfo_hash
	return self.conninfo.each_with_object({}) do |info, hash|
		hash[ info[:keyword].to_sym ] = info[:val]
	end
end


  








  

    #consume_input    



  

    

If input is available from the server, consume it. After calling consume_input, you can check #is_busy or notifies to see if the state has changed.


  



  [ GitHub ]


  

  


# File 'ext/pg_connection.c', line 2251



static VALUE
pgconn_consume_input(VALUE self)
{
	PGconn *conn = pg_get_pgconn(self);
	/* returns 0 on error */
	if(PQconsumeInput(conn) == 0) {
		pgconn_close_socket_io(self);
		pg_raise_conn_error( rb_eConnectionBad, self, "%s", PQerrorMessage(conn));
	}

	return Qnil;
}


  








  

    #copy_data(sql [, coder] ) {|sql_result| ... } ⇒ PG::Result   



  

    

Execute a copy process for transferring data to or from the server.



This issues the SQL COPY command via #exec. The response to this (if there is no error in the command) is a Result object that is passed to the block, bearing a status code of PGRES_COPY_OUT or PGRES_COPY_IN (depending on the specified copy direction). The application should then use #put_copy_data or #get_copy_data to receive or transmit data rows and should return from the block when finished.



#copy_data returns another Result object when the data transfer is complete. An exception is raised if some problem was encountered, so it isn’t required to make use of any of them. At this point further SQL commands can be issued via #exec. (It is not possible to execute other SQL commands using the same connection while the COPY operation is in progress.)



This method ensures, that the copy process is properly terminated in case of client side or server side failures. Therefore, in case of blocking mode of operation, #copy_data is preferred to raw calls of #put_copy_data, #get_copy_data and #put_copy_end.



coder can be a Coder derivation (typically TextEncoder::CopyRow or TextDecoder::CopyRow). This enables encoding of data fields given to #put_copy_data or decoding of fields received by #get_copy_data.



Example with CSV input format:



conn.exec "create table my_table (a text,b text,c text,d text)"
conn.copy_data "COPY my_table FROM STDIN CSV" do
  conn.put_copy_data "some,data,to,copy\n"
  conn.put_copy_data "more,data,to,copy\n"
end



This creates my_table and inserts two CSV rows.



The same with text format encoder TextEncoder::CopyRow and Array input:



enco = PG::TextEncoder::CopyRow.new
conn.copy_data "COPY my_table FROM STDIN", enco do
  conn.put_copy_data ['some', 'data', 'to', 'copy']
  conn.put_copy_data ['more', 'data', 'to', 'copy']
end



All 4 CopyRow classes can take a type map to specify how the columns are mapped to and from the database format. For details see the particular CopyRow class description.



BinaryEncoder::CopyRow can be used to send data in binary format to the server. In this case copy_data generates the header and trailer data automatically:



enco = PG::BinaryEncoder::CopyRow.new
conn.copy_data "COPY my_table FROM STDIN (FORMAT binary)", enco do
  conn.put_copy_data ['some', 'data', 'to', 'copy']
  conn.put_copy_data ['more', 'data', 'to', 'copy']
end



Example with CSV output format:



conn.copy_data "COPY my_table TO STDOUT CSV" do
  while row=conn.get_copy_data
    p row
  end
end



This prints all rows of my_table to stdout:



"some,data,to,copy\n"
"more,data,to,copy\n"



The same with text format decoder TextDecoder::CopyRow and Array output:



deco = PG::TextDecoder::CopyRow.new
conn.copy_data "COPY my_table TO STDOUT", deco do
  while row=conn.get_copy_data
    p row
  end
end



This receives all rows of my_table as ruby array:



["some", "data", "to", "copy"]
["more", "data", "to", "copy"]



Also BinaryDecoder::CopyRow can be used to retrieve data in binary format from the server. In this case the header and trailer data is processed by the decoder and the remaining nil from get_copy_data is processed by copy_data, so that binary data can be processed equally to text data:



deco = PG::BinaryDecoder::CopyRow.new
conn.copy_data "COPY my_table TO STDOUT (FORMAT binary)", deco do
  while row=conn.get_copy_data
    p row
  end
end



This receives all rows of my_table as ruby array:



["some", "data", "to", "copy"]
["more", "data", "to", "copy"]


  





  
Raises:





  [ GitHub ]


  

  


# File 'lib/pg/connection.rb', line 214



def copy_data( sql, coder=nil )
	raise PG::NotInBlockingMode.new("copy_data can not be used in nonblocking mode", connection: self) if nonblocking?
	res = exec( sql )

	case res.result_status
	when PGRES_COPY_IN
		begin
			if coder && res.binary_tuples == 1
				# Binary file header (11 byte signature, 32 bit flags and 32 bit extension length)
				put_copy_data(BinarySignature + ("\x00" * 8))
			end

			if coder
				old_coder = self.encoder_for_put_copy_data
				self.encoder_for_put_copy_data = coder
			end

			yield res
		rescue Exception => err
			errmsg = "%s while copy data: %s" % [ err.class.name, err.message ]
			begin
				put_copy_end( errmsg )
			rescue PG::Error
				# Ignore error in cleanup to avoid losing original exception
			end
			discard_results
			raise err
		else
			begin
				self.encoder_for_put_copy_data = old_coder if coder

				if coder && res.binary_tuples == 1
					put_copy_data("\xFF\xFF") # Binary file trailer 16 bit "-1"
				end

				put_copy_end
			rescue PG::Error => err
				raise PG::LostCopyState.new("#{err} (probably by executing another SQL query while running a COPY command)", connection: self)
			end
			get_last_result
		ensure
			self.encoder_for_put_copy_data = old_coder if coder
		end

	when PGRES_COPY_OUT
		begin
			if coder
				old_coder = self.decoder_for_get_copy_data
				self.decoder_for_get_copy_data = coder
			end
			yield res
		rescue Exception
			cancel
			discard_results
			raise
		else
			if coder && res.binary_tuples == 1
				# There are two end markers in binary mode: file trailer and the final nil.
				# The file trailer is expected to be processed by BinaryDecoder::CopyRow and already returns nil, so that the remaining NULL from PQgetCopyData is retrieved here:
				if get_copy_data
					discard_results
					raise PG::NotAllCopyDataRetrieved.new("Not all binary COPY data retrieved", connection: self)
				end
			end
			res = get_last_result
			if !res
				discard_results
				raise PG::LostCopyState.new("Lost COPY state (probably by executing another SQL query while running a COPY command)", connection: self)
			elsif res.result_status != PGRES_COMMAND_OK
				discard_results
				raise PG::NotAllCopyDataRetrieved.new("Not all COPY data retrieved", connection: self)
			end
			res
		ensure
			self.decoder_for_get_copy_data = old_coder if coder
		end

	else
		raise ArgumentError, "SQL command is no COPY statement: #{sql}"
	end
end


  








  

    #db    



  

    

Returns the connected database name.


  



  [ GitHub ]


  

  


# File 'ext/pg_connection.c', line 632



static VALUE
pgconn_db(VALUE self)
{
	char *db = PQdb(pg_get_pgconn(self));
	if (!db) return Qnil;
	return rb_str_new2(db);
}


  








  

    #describe_portal(portal_name)  ⇒ PG::Result     Also known as: #async_describe_portal
  



  

    

Retrieve information about the portal portal_name.



See also corresponding libpq function.


  



  [ GitHub ]


  

  


# File 'ext/pg_connection.c', line 3592



static VALUE
pgconn_async_describe_portal(VALUE self, VALUE portal)
{
	return pgconn_async_describe_close_prepared_potral(self, portal, pgconn_send_describe_portal);
}


  








  

    #describe_prepared(statement_name)  ⇒ PG::Result     Also known as: #async_describe_prepared
  



  

    

Retrieve information about the prepared statement statement_name.



See also corresponding libpq function.


  



  [ GitHub ]


  

  


# File 'ext/pg_connection.c', line 3607



static VALUE
pgconn_async_describe_prepared(VALUE self, VALUE stmt_name)
{
	return pgconn_async_describe_close_prepared_potral(self, stmt_name, pgconn_send_describe_prepared);
}


  








  

    #discard_results    



  

    

Silently discard any prior query result that application didn’t eat. This is internally used prior to #exec and sibling methods. It doesn’t raise an exception on connection errors, but returns false instead.



Returns:


  • 

    nil  when the connection is already idle
    

  • 

    true  when some results have been discarded
    

  • 

    false  when a failure occurred and the connection was closed
    



  



  [ GitHub ]


  

  


# File 'ext/pg_connection.c', line 3284



static VALUE
pgconn_discard_results(VALUE self)
{
	PGconn *conn = pg_get_pgconn(self);
	VALUE socket_io;

	switch( PQtransactionStatus(conn) ) {
		case PQTRANS_IDLE:
		case PQTRANS_INTRANS:
		case PQTRANS_INERROR:
			return Qnil;
		default:;
	}

	socket_io = pgconn_socket_io(self);

	for(;;) {
		PGresult *cur;
		int status;

		/* pgconn_block() raises an exception in case of errors.
		* To avoid this call pg_rb_io_wait() and PQconsumeInput() without rb_raise().
		*/
		while( gvl_PQisBusy(conn) ){
			int events;

			switch( PQflush(conn) ) {
				case 1:
					events = RB_NUM2INT(pg_rb_io_wait(socket_io, RB_INT2NUM(PG_RUBY_IO_READABLE | PG_RUBY_IO_WRITABLE), Qnil));
					if (events & PG_RUBY_IO_READABLE){
						if ( PQconsumeInput(conn) == 0 ) goto error;
					}
					break;
				case 0:
					pg_rb_io_wait(socket_io, RB_INT2NUM(PG_RUBY_IO_READABLE), Qnil);
					if ( PQconsumeInput(conn) == 0 ) goto error;
					break;
				default:
					goto error;
			}
		}

		cur = gvl_PQgetResult(conn);
		if( cur == NULL) break;

		status = PQresultStatus(cur);
		PQclear(cur);
		if (status == PGRES_COPY_IN){
			while( gvl_PQputCopyEnd(conn, "COPY terminated by new query or discard_results") == 0 ){
				pgconn_async_flush(self);
			}
		}
		if (status == PGRES_COPY_OUT){
			for(;;) {
				char *buffer = NULL;
				int st = gvl_PQgetCopyData(conn, &buffer, 1);
				if( st == 0 ) {
					/* would block -> wait for readable data */
					pg_rb_io_wait(socket_io, RB_INT2NUM(PG_RUBY_IO_READABLE), Qnil);
					if ( PQconsumeInput(conn) == 0 ) goto error;
				} else if( st > 0 ) {
					/* some data retrieved -> discard it */
					PQfreemem(buffer);
				} else {
					/* no more data */
					break;
				}
			}
		}
	}

	return Qtrue;

error:
	pgconn_close_socket_io(self);
	return Qfalse;
}


  








  

    #encrypt_password(password, username, algorithm = nil)  ⇒ String     Also known as: #async_encrypt_password
  



  

    

This function is intended to be used by client applications that wish to send commands like ALTER USER joe PASSWORD 'pwd'. It is good practice not to send the original cleartext password in such a command, because it might be exposed in command logs, activity displays, and so on. Instead, use this function to convert the password to encrypted form before it is sent.



The password and username arguments are the cleartext password, and the SQL name of the user it is for. algorithm specifies the encryption algorithm to use to encrypt the password. Currently supported algorithms are md5 and scram-sha-256 (on and off are also accepted as aliases for md5, for compatibility with older server versions). Note that support for scram-sha-256 was introduced in PostgreSQL version 10, and will not work correctly with older server versions. If algorithm is omitted or nil, this function will query the server for the current value of the password_encryption setting. That can block, and will fail if the current transaction is aborted, or if the connection is busy executing another query. If you wish to use the default algorithm for the server but want to avoid blocking, query password_encryption yourself before calling #encrypt_password, and pass that value as the algorithm.



Return value is the encrypted password. The caller can assume the string doesn’t contain any special characters that would require escaping.



Available since PostgreSQL-10. See also corresponding libpq function.


  



  [ GitHub ]


  

  


# File 'lib/pg/connection.rb', line 579



def encrypt_password( password, username, algorithm=nil )
	algorithm ||= exec("SHOW password_encryption").getvalue(0,0)
	sync_encrypt_password(password, username, algorithm)
end


  








  

    #enter_pipeline_mode  ⇒ nil   



  

    

Causes a connection to enter pipeline mode if it is currently idle or already in pipeline mode.



Raises Error and has no effect if the connection is not currently idle, i.e., it has a result ready, or it is waiting for more input from the server, etc. This function does not actually send anything to the server, it just changes the libpq connection state.



See the PostgreSQL documentation.



Available since PostgreSQL-14


  



  [ GitHub ]


  

  


# File 'ext/pg_connection.c', line 3772



static VALUE
pgconn_enter_pipeline_mode(VALUE self)
{
	PGconn *conn = pg_get_pgconn(self);
	int res = PQenterPipelineMode(conn);
	if( res != 1 )
		pg_raise_conn_error( rb_ePGerror, self, "%s", PQerrorMessage(conn));

	return Qnil;
}


  








  

    #error_message  ⇒ String   



  

    

Returns the error message most recently generated by an operation on the connection.



Nearly all libpq functions will set a message for conn.error_message if they fail. Note that by libpq convention, a nonempty error_message result can consist of multiple lines, and will include a trailing newline.


  



  [ GitHub ]


  

  


# File 'ext/pg_connection.c', line 884



static VALUE
pgconn_error_message(VALUE self)
{
	char *error = PQerrorMessage(pg_get_pgconn(self));
	if (!error) return Qnil;
	return rb_str_new2(error);
}


  








  

    

      #escape_bytea(string)  ⇒ String 
      #escape_bytea(string)  ⇒ String 
    

  



  

    

Alias for .escape_bytea.


  





  








  

    #escape_identifier(str)  ⇒ String   



  

    

Escape an arbitrary String str as an identifier.



This method does the same as #quote_ident with a String argument, but it doesn’t support an Array argument and it makes use of libpq to process the string.


  



  [ GitHub ]


  

  


# File 'ext/pg_connection.c', line 1804



static VALUE
pgconn_escape_identifier(VALUE self, VALUE string)
{
	t_pg_connection *this = pg_get_connection_safe( self );
	char *escaped = NULL;
	VALUE result = Qnil;
	int enc_idx = this->enc_idx;

	StringValueCStr(string);
	if( ENCODING_GET(string) != enc_idx ){
		string = rb_str_export_to_enc(string, rb_enc_from_index(enc_idx));
	}

	escaped = PQescapeIdentifier(this->pgconn, RSTRING_PTR(string), RSTRING_LEN(string));
	if (escaped == NULL)
		pg_raise_conn_error( rb_ePGerror, self, "%s", PQerrorMessage(this->pgconn));

	result = rb_str_new2(escaped);
	PQfreemem(escaped);
	PG_ENCODING_SET_NOCHECK(result, enc_idx);

	return result;
}


  








  

    #escape_literal(str)  ⇒ String   



  

    

Escape an arbitrary String str as a literal.



See also TextEncoder::QuotedLiteral for a type cast integrated version of this function.


  



  [ GitHub ]


  

  


# File 'ext/pg_connection.c', line 1770



static VALUE
pgconn_escape_literal(VALUE self, VALUE string)
{
	t_pg_connection *this = pg_get_connection_safe( self );
	char *escaped = NULL;
	VALUE result = Qnil;
	int enc_idx = this->enc_idx;

	StringValueCStr(string);
	if( ENCODING_GET(string) != enc_idx ){
		string = rb_str_export_to_enc(string, rb_enc_from_index(enc_idx));
	}

	escaped = PQescapeLiteral(this->pgconn, RSTRING_PTR(string), RSTRING_LEN(string));
	if (escaped == NULL)
		pg_raise_conn_error( rb_ePGerror, self, "%s", PQerrorMessage(this->pgconn));

	result = rb_str_new2(escaped);
	PQfreemem(escaped);
	PG_ENCODING_SET_NOCHECK(result, enc_idx);

	return result;
}


  








  

    

      #escape(str)  ⇒ String 
      #escape_string(str)  ⇒ String 
    

  



  

    

Alias for .escape.


  





  








  

    

      #exec(sql)  ⇒ PG::Result 
      #exec(sql) {|pg_result| ... } 
    

    Also known as: #async_exec
  



  

    

Sends SQL query request specified by sql to PostgreSQL. On success, it returns a Result instance with all result rows and columns. On failure, it raises a Error.



For backward compatibility, if you pass more than one parameter to this method, it will call #exec_params for you. New code should explicitly use #exec_params if argument placeholders are used.



If the optional code block is given, it will be passed result as an argument, and the Result object will  automatically be cleared when the block terminates. In this instance, conn.exec returns the value of the block.



#exec is an alias for #async_exec which is almost identical to #sync_exec . #sync_exec is implemented on the simpler synchronous command processing API of libpq, whereas #async_exec is implemented on the asynchronous API and on ruby’s IO mechanisms. Only #async_exec is compatible to Fiber.scheduler based asynchronous IO processing introduced in ruby-3.0. Both methods ensure that other threads can process while waiting for the server to complete the request, but #sync_exec blocks all signals to be processed until the query is finished. This is most notably visible by a delayed reaction to Control+C. It’s not recommended to use explicit sync or async variants but #exec instead, unless you have a good reason to do so.



See also corresponding libpq function.


  





  


  [ GitHub ]


  

  


# File 'ext/pg_connection.c', line 3390



static VALUE
pgconn_async_exec(int argc, VALUE *argv, VALUE self)
{
	VALUE rb_pgresult = Qnil;

	pgconn_discard_results( self );
	pgconn_send_query( argc, argv, self );
	rb_pgresult = pgconn_async_get_last_result( self );

	if ( rb_block_given_p() ) {
		return rb_ensure( rb_yield, rb_pgresult, pg_result_clear, rb_pgresult );
	}
	return rb_pgresult;
}


  








  

    

      #exec_params(sql, params [, result_format [, type_map ]] )  ⇒ nil 
      #exec_params(sql, params [, result_format [, type_map ]] ) {|pg_result| ... } 
    

    Also known as: #async_exec_params
  



  

    

Sends SQL query request specified by sql to PostgreSQL using placeholders for parameters.



Returns a Result instance on success. On failure, it raises a Error.



params is an array of the bind parameters for the SQL query. Each element of the params array may be either:



a hash of the form:
  {:value  => String (value of bind parameter)
   :type   => Integer (oid of type of bind parameter)
   :format => Integer (0 for text, 1 for binary)
  }
or, it may be a String. If it is a string, that is equivalent to the hash:
  { :value => <string value>, :type => 0, :format => 0 }



PostgreSQL bind parameters are represented as $1, $2, $3, etc., inside the SQL query. The 0th element of the params array is bound to $1, the 1st element is bound to $2, etc. nil is treated as NULL.



If the types are not specified, they will be inferred by PostgreSQL. Instead of specifying type oids, it’s recommended to simply add explicit casts in the query to ensure that the right type is used.



For example: “SELECT $1::int”



The optional result_format should be 0 for text results, 1 for binary.



type_map can be a TypeMap derivation (such as BasicTypeMapForQueries). This will type cast the params from various Ruby types before transmission based on the encoders defined by the type map. When a type encoder is used the format and oid of a given bind parameter are retrieved from the encoder instead out of the hash form described above.



If the optional code block is given, it will be passed result as an argument, and the Result object will  automatically be cleared when the block terminates. In this instance, conn.exec returns the value of the block.



The primary advantage of #exec_params over #exec is that parameter values can be separated from the command string, thus avoiding the need for tedious and error-prone quoting and escaping. Unlike #exec, #exec_params allows at most one SQL command in the given string. (There can be semicolons in it, but not more than one nonempty command.) This is a limitation of the underlying protocol, but has some usefulness as an extra defense against SQL-injection attacks.



See also corresponding libpq function.


  





  


  [ GitHub ]


  

  


# File 'ext/pg_connection.c', line 3456



static VALUE
pgconn_async_exec_params(int argc, VALUE *argv, VALUE self)
{
	VALUE rb_pgresult = Qnil;

	pgconn_discard_results( self );
	/* If called with no or nil parameters, use PQsendQuery for compatibility */
	if ( argc == 1 || (argc >= 2 && argc <= 4 && NIL_P(argv[1]) )) {
		pg_deprecated(3, ("forwarding async_exec_params to async_exec is deprecated"));
		pgconn_send_query( argc, argv, self );
	} else {
		pgconn_send_query_params( argc, argv, self );
	}
	rb_pgresult = pgconn_async_get_last_result( self );

	if ( rb_block_given_p() ) {
		return rb_ensure( rb_yield, rb_pgresult, pg_result_clear, rb_pgresult );
	}
	return rb_pgresult;
}


  








  

    

      #exec_prepared(statement_name [, params, result_format[, type_map]] )  ⇒ PG::Result 
      #exec_prepared(statement_name [, params, result_format[, type_map]] ) {|pg_result| ... } 
    

    Also known as: #async_exec_prepared
  



  

    

Execute prepared named statement specified by statement_name. Returns a Result instance on success. On failure, it raises a Error.



params is an array of the optional bind parameters for the SQL query. Each element of the params array may be either:



a hash of the form:
  {:value  => String (value of bind parameter)
   :format => Integer (0 for text, 1 for binary)
  }
or, it may be a String. If it is a string, that is equivalent to the hash:
  { :value => <string value>, :format => 0 }



PostgreSQL bind parameters are represented as $1, $2, $3, etc., inside the SQL query. The 0th element of the params array is bound to $1, the 1st element is bound to $2, etc. nil is treated as NULL.



The optional result_format should be 0 for text results, 1 for binary.



type_map can be a TypeMap derivation (such as BasicTypeMapForQueries). This will type cast the params from various Ruby types before transmission based on the encoders defined by the type map. When a type encoder is used the format and oid of a given bind parameter are retrieved from the encoder instead out of the hash form described above.



If the optional code block is given, it will be passed result as an argument, and the Result object will  automatically be cleared when the block terminates. In this instance, conn.exec_prepared returns the value of the block.



See also corresponding libpq function.


  





  


  [ GitHub ]


  

  


# File 'ext/pg_connection.c', line 3553



static VALUE
pgconn_async_exec_prepared(int argc, VALUE *argv, VALUE self)
{
	VALUE rb_pgresult = Qnil;

	pgconn_discard_results( self );
	pgconn_send_query_prepared( argc, argv, self );
	rb_pgresult = pgconn_async_get_last_result( self );

	if ( rb_block_given_p() ) {
		return rb_ensure( rb_yield, rb_pgresult, pg_result_clear, rb_pgresult );
	}
	return rb_pgresult;
}


  








  

    #exit_pipeline_mode  ⇒ nil   



  

    

Causes a connection to exit pipeline mode if it is currently in pipeline mode with an empty queue and no pending results.



Takes no action if not in pipeline mode. Raises Error if the current statement isn’t finished processing, or PQgetResult has not been called to collect results from all previously sent query.



Available since PostgreSQL-14


  



  [ GitHub ]


  

  


# File 'ext/pg_connection.c', line 3794



static VALUE
pgconn_exit_pipeline_mode(VALUE self)
{
	PGconn *conn = pg_get_pgconn(self);
	int res = PQexitPipelineMode(conn);
	if( res != 1 )
		pg_raise_conn_error( rb_ePGerror, self, "%s", PQerrorMessage(conn));

	return Qnil;
}


  








  

    #external_encoding  ⇒ Encoding   



  

    

Return the server_encoding of the connected database as a Ruby Encoding object. The SQL_ASCII encoding is mapped to to ASCII_8BIT.


  



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# File 'ext/pg_connection.c', line 4305



static VALUE
pgconn_external_encoding(VALUE self)
{
	t_pg_connection *this = pg_get_connection_safe( self );
	rb_encoding *enc = NULL;
	const char *pg_encname = NULL;

	pg_encname = PQparameterStatus( this->pgconn, "server_encoding" );
	enc = pg_get_pg_encname_as_rb_encoding( pg_encname );
	return rb_enc_from_encoding( enc );
}


  








  

    

      #close  
      #finish  
    

  



  

    

Alias for #close.


  





  








  

    #flush  ⇒ Boolean     Also known as: #async_flush
  



  

    

Attempts to flush any queued output data to the server. Returns true if data is successfully flushed, false if not. It can only return false if connection is in nonblocking mode. Raises Error if some other failure occurred.


  



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# File 'ext/pg_connection.c', line 2582



static VALUE
pgconn_async_flush(VALUE self)
{
	while( pgconn_sync_flush(self) == Qfalse ){
		/* wait for the socket to become read- or write-ready */
		int events;
		VALUE socket_io = pgconn_socket_io(self);
		events = RB_NUM2INT(pg_rb_io_wait(socket_io, RB_INT2NUM(PG_RUBY_IO_READABLE | PG_RUBY_IO_WRITABLE), Qnil));

		if (events & PG_RUBY_IO_READABLE){
			pgconn_consume_input(self);
		}
	}
	return Qtrue;
}


  








  

    #get_client_encoding  ⇒ String   



  

    

Returns the client encoding as a String.


  



  [ GitHub ]


  

  


# File 'ext/pg_connection.c', line 3051



static VALUE
pgconn_get_client_encoding(VALUE self)
{
	char *encoding = (char *)pg_encoding_to_char(PQclientEncoding(pg_get_pgconn(self)));
	return rb_str_new2(encoding);
}


  








  

    #get_copy_data([ nonblock = false [, decoder = nil ]] )  ⇒ Object     Also known as: #async_get_copy_data
  



  

    

Return one row of data, nil if the copy is done, or false if the call would block (only possible if nonblock is true).



If decoder is not set or nil, data is returned as binary string.



If decoder is set to a Coder derivation, the return type depends on this decoder. TextDecoder::CopyRow decodes the received data fields from one row of PostgreSQL’s COPY text format to an Array of Strings. Optionally the decoder can type cast the single fields to various Ruby types in one step, if PG::TextDecoder::CopyRow#type_map is set accordingly.



See also #copy_data.


  



  [ GitHub ]


  

  


# File 'lib/pg/connection.rb', line 428



def get_copy_data(async=false, decoder=nil)
	if async
		return sync_get_copy_data(async, decoder)
	else
		while (res=sync_get_copy_data(true, decoder)) == false
			socket_io.wait_readable
			consume_input
		end
		return res
	end
end


  








  

    #get_last_result()  ⇒ PG::Result     Also known as: #async_get_last_result
  



  

    

This function retrieves all available results on the current connection (from previously issued asynchronous commands like send_query()) and returns the last non-NULL result, or nil if no results are available.



If the last result contains a bad result_status, an appropriate exception is raised.



This function is similar to #get_result except that it is designed to get one and only one result and that it checks the result state.


  



  [ GitHub ]


  

  


# File 'ext/pg_connection.c', line 3234



static VALUE
pgconn_async_get_last_result(VALUE self)
{
	PGconn *conn = pg_get_pgconn(self);
	VALUE rb_pgresult = Qnil;
	PGresult *cur, *prev;

	cur = prev = NULL;
	for(;;) {
		int status;

		/* Wait for input before reading each result.
		 * That way we support the ruby-3.x IO scheduler and don't block other ruby threads.
		 */
		wait_socket_readable(self, NULL, get_result_readable);

		cur = gvl_PQgetResult(conn);
		if (cur == NULL)
			break;

		if (prev) PQclear(prev);
		prev = cur;

		status = PQresultStatus(cur);
		if (status == PGRES_COPY_OUT || status == PGRES_COPY_IN || status == PGRES_COPY_BOTH)
			break;
	}

	if (prev) {
		rb_pgresult = pg_new_result( prev, self );
		pg_result_check(rb_pgresult);
	}

	return rb_pgresult;
}


  








  

    

      #get_result  ⇒ PG::Result 
      #get_result {|pg_result| ... } 
    

    Also known as: #async_get_result
  



  

    

Blocks waiting for the next result from a call to #send_query (or another asynchronous command), and returns it. Returns nil if no more results are available.



Note: call this function repeatedly until it returns nil, or else you will not be able to issue further commands.



If the optional code block is given, it will be passed result as an argument, and the Result object will  automatically be cleared when the block terminates. In this instance, conn.exec returns the value of the block.


  





  


  [ GitHub ]


  

  


# File 'lib/pg/connection.rb', line 405



def get_result
	block
	sync_get_result
end


  








  

    #host    



  

    

Returns the server host name of the active connection. This can be a host name, an IP address, or a directory path if the connection is via Unix socket. (The path case can be distinguished because it will always be an absolute path, beginning with / .)



If the connection parameters specified both host and hostaddr, then host will return the host information. If only hostaddr was specified, then that is returned. If multiple hosts were specified in the connection parameters, host returns the host actually connected to.



If there is an error producing the host information (perhaps if the connection has not been fully established or there was an error), it returns an empty string.



If multiple hosts were specified in the connection parameters, it is not possible to rely on the result of host until the connection is established. The status of the connection can be checked using the function #status .


  



  [ GitHub ]


  

  


# File 'ext/pg_connection.c', line 685



static VALUE
pgconn_host(VALUE self)
{
	char *host = PQhost(pg_get_pgconn(self));
	if (!host) return Qnil;
	return rb_str_new2(host);
}


  








  

    #hostaddr    



  

    

Returns the server IP address of the active connection. This can be the address that a host name resolved to, or an IP address provided through the hostaddr parameter. If there is an error producing the host information (perhaps if the connection has not been fully established or there was an error), it returns an empty string.


  



  [ GitHub ]


  

  


# File 'ext/pg_connection.c', line 704



static VALUE
pgconn_hostaddr(VALUE self)
{
	char *host = PQhostaddr(pg_get_pgconn(self));
	if (!host) return Qnil;
	return rb_str_new2(host);
}


  








  

    #inspect  
  



  

    

Return a String representation of the object suitable for debugging.


  



  [ GitHub ]


  

  


# File 'lib/pg/connection.rb', line 100



def inspect
	str = self.to_s
	str[-1,0] = if finished?
		" finished"
	else
		stats = []
		stats << " status=#{ PG.constants.grep(/CONNECTION_/).find{|c| PG.const_get(c) == status} }" if status != CONNECTION_OK
		stats << " transaction_status=#{ PG.constants.grep(/PQTRANS_/).find{|c| PG.const_get(c) == transaction_status} }" if transaction_status != PG::PQTRANS_IDLE
		stats << " nonblocking=#{ isnonblocking }" if isnonblocking
		stats << " pipeline_status=#{ PG.constants.grep(/PQ_PIPELINE_/).find{|c| PG.const_get(c) == pipeline_status} }" if respond_to?(:pipeline_status) && pipeline_status != PG::PQ_PIPELINE_OFF
		stats << " client_encoding=#{ get_client_encoding }" if get_client_encoding != "UTF8"
		stats << " type_map_for_results=#{ type_map_for_results.to_s }" unless type_map_for_results.is_a?(PG::TypeMapAllStrings)
		stats << " type_map_for_queries=#{ type_map_for_queries.to_s }" unless type_map_for_queries.is_a?(PG::TypeMapAllStrings)
		stats << " encoder_for_put_copy_data=#{ encoder_for_put_copy_data.to_s }" if encoder_for_put_copy_data
		stats << " decoder_for_get_copy_data=#{ decoder_for_get_copy_data.to_s }" if decoder_for_get_copy_data
		" host=#{host} port=#{port} user=#{user}#{stats.join}"
	end
	return str
end


  








  

    #is_busy  ⇒ Boolean   



  

    

Returns true if a command is busy, that is, if #get_result would block. Otherwise returns false.


  



  [ GitHub ]


  

  


# File 'ext/pg_connection.c', line 2271



static VALUE
pgconn_is_busy(VALUE self)
{
	return gvl_PQisBusy(pg_get_pgconn(self)) ? Qtrue : Qfalse;
}


  








  

    #isnonblocking  ⇒ Boolean     Also known as: #async_isnonblocking, #nonblocking?
  



  

    

Returns the blocking status of the database connection. Returns true if the connection is set to nonblocking mode and false if blocking.


  



  [ GitHub ]


  

  


# File 'lib/pg/connection.rb', line 476



def isnonblocking
	false
end


  








  

    

      #loclose(lo_desc)  ⇒ nil 
      #lo_close(lo_desc)  ⇒ nil 
    

  



  

    

Alias for #loclose.


  





  








  

    

      #locreat([mode])  ⇒ Integer 
      #lo_creat([mode])  ⇒ Integer 
    

  



  

    

Alias for #locreat.


  





  








  

    

      #locreate(oid)  ⇒ Integer 
      #lo_create(oid)  ⇒ Integer 
    

  



  

    

Alias for #locreate.


  





  








  

    

      #loexport(oid, file)  ⇒ nil 
      #lo_export(oid, file)  ⇒ nil 
    

  



  

    

Alias for #loexport.


  





  








  

    

      #loimport(file)  ⇒ Integer 
      #lo_import(file)  ⇒ Integer 
    

  



  

    

Alias for #loimport.


  





  








  

    

      #loseek(lo_desc, offset, whence)  ⇒ Integer 
      #lo_lseek(lo_desc, offset, whence)  ⇒ Integer 
    

  



  

    

Alias for #loseek.


  





  








  

    

      #loopen(oid, [mode])  ⇒ Integer 
      #lo_open(oid, [mode])  ⇒ Integer 
    

  



  

    

Alias for #loopen.


  





  








  

    

      #loread(lo_desc, len)  ⇒ String 
      #lo_read(lo_desc, len)  ⇒ String 
    

  



  

    

Alias for #loread.


  





  








  

    

      #loseek(lo_desc, offset, whence)  ⇒ Integer 
      #lo_seek(lo_desc, offset, whence)  ⇒ Integer 
    

  



  

    

Alias for #loseek.


  









  

    

      #lotell(lo_desc)  ⇒ Integer 
      #lo_tell(lo_desc)  ⇒ Integer 
    

  



  

    

Alias for #lotell.


  





  








  

    

      #lotruncate(lo_desc, len)  ⇒ nil 
      #lo_truncate(lo_desc, len)  ⇒ nil 
    

  



  

    

Alias for #lotruncate.


  





  










  

    

      #lowrite(lo_desc, buffer)  ⇒ Integer 
      #lo_write(lo_desc, buffer)  ⇒ Integer 
    

  



  

    

Alias for #lowrite.


  





  








  

    #loclose(lo_desc)  ⇒ nil     Also known as: #lo_close
  



  

    

Closes the postgres large object of lo_desc.


  



  [ GitHub ]


  

  


# File 'ext/pg_connection.c', line 4181



static VALUE
pgconn_loclose(VALUE self, VALUE in_lo_desc)
{
	PGconn *conn = pg_get_pgconn(self);
	int lo_desc = NUM2INT(in_lo_desc);
	int ret;

	BLOCKING_BEGIN(conn)
		ret = lo_close(conn,lo_desc);
	BLOCKING_END(conn)

	if(ret < 0)
		pg_raise_conn_error( rb_ePGerror, self, "lo_close failed");

	return Qnil;
}


  








  

    #locreat([mode])  ⇒ Integer     Also known as: #lo_creat
  



  

    

Creates a large object with mode mode. Returns a large object Oid. On failure, it raises Error.


  



  [ GitHub ]


  

  


# File 'ext/pg_connection.c', line 3898



static VALUE
pgconn_locreat(int argc, VALUE *argv, VALUE self)
{
	Oid lo_oid;
	int mode;
	VALUE nmode;
	PGconn *conn = pg_get_pgconn(self);

	if (rb_scan_args(argc, argv, "01", &nmode) == 0)
		mode = INV_READ;
	else
		mode = NUM2INT(nmode);

	BLOCKING_BEGIN(conn)
		lo_oid = lo_creat(conn, mode);
	BLOCKING_END(conn)

	if (lo_oid == 0)
		pg_raise_conn_error( rb_ePGerror, self, "lo_creat failed");

	return UINT2NUM(lo_oid);
}


  








  

    #locreate(oid)  ⇒ Integer     Also known as: #lo_create
  



  

    

Creates a large object with oid oid. Returns the large object Oid. On failure, it raises Error.


  



  [ GitHub ]


  

  


# File 'ext/pg_connection.c', line 3928



static VALUE
pgconn_locreate(VALUE self, VALUE in_lo_oid)
{
	Oid ret, lo_oid;
	PGconn *conn = pg_get_pgconn(self);
	lo_oid = NUM2UINT(in_lo_oid);

	ret = lo_create(conn, lo_oid);
	if (ret == InvalidOid)
		pg_raise_conn_error( rb_ePGerror, self, "lo_create failed");

	return UINT2NUM(ret);
}


  








  

    #loexport(oid, file)  ⇒ nil     Also known as: #lo_export
  



  

    

Saves a large object of oid to a file.


  



  [ GitHub ]


  

  


# File 'ext/pg_connection.c', line 3975



static VALUE
pgconn_loexport(VALUE self, VALUE lo_oid, VALUE filename)
{
	PGconn *conn = pg_get_pgconn(self);
	Oid oid;
	int ret;
	Check_Type(filename, T_STRING);

	oid = NUM2UINT(lo_oid);

	BLOCKING_BEGIN(conn)
		ret = lo_export(conn, oid, StringValueCStr(filename));
	BLOCKING_END(conn)

	if (ret < 0) {
		pg_raise_conn_error( rb_ePGerror, self, "%s", PQerrorMessage(conn));
	}
	return Qnil;
}


  








  

    #loimport(file)  ⇒ Integer     Also known as: #lo_import
  



  

    

Import a file to a large object. Returns a large object Oid.



On failure, it raises a Error.


  



  [ GitHub ]


  

  


# File 'ext/pg_connection.c', line 3950



static VALUE
pgconn_loimport(VALUE self, VALUE filename)
{
	Oid lo_oid;

	PGconn *conn = pg_get_pgconn(self);

	Check_Type(filename, T_STRING);

	BLOCKING_BEGIN(conn)
		lo_oid = lo_import(conn, StringValueCStr(filename));
	BLOCKING_END(conn)

	if (lo_oid == 0) {
		pg_raise_conn_error( rb_ePGerror, self, "%s", PQerrorMessage(conn));
	}
	return UINT2NUM(lo_oid);
}


  








  

    

      #loseek(lo_desc, offset, whence)  ⇒ Integer 
      #lolseek(lo_desc, offset, whence)  ⇒ Integer 
    

  



  

    

Alias for #loseek.


  









  

    #loopen(oid, [mode])  ⇒ Integer     Also known as: #lo_open
  



  

    

Open a large object of oid. Returns a large object descriptor instance on success. The mode argument specifies the mode for the opened large object,which is either INV_READ, or INV_WRITE.



If mode is omitted, the default is INV_READ.


  



  [ GitHub ]


  

  


# File 'ext/pg_connection.c', line 4005



static VALUE
pgconn_loopen(int argc, VALUE *argv, VALUE self)
{
	Oid lo_oid;
	int fd, mode;
	VALUE nmode, selfid;
	PGconn *conn = pg_get_pgconn(self);

	rb_scan_args(argc, argv, "11", &selfid, &nmode);
	lo_oid = NUM2UINT(selfid);
	if(NIL_P(nmode))
		mode = INV_READ;
	else
		mode = NUM2INT(nmode);

	BLOCKING_BEGIN(conn)
		fd = lo_open(conn, lo_oid, mode);
	BLOCKING_END(conn)

	if(fd < 0) {
		pg_raise_conn_error( rb_ePGerror, self, "can't open large object: %s", PQerrorMessage(conn));
	}
	return INT2FIX(fd);
}


  








  

    #loread(lo_desc, len)  ⇒ String     Also known as: #lo_read
  



  

    

Attempts to read len bytes from large object lo_desc, returns resulting data.


  



  [ GitHub ]


  

  


# File 'ext/pg_connection.c', line 4068



static VALUE
pgconn_loread(VALUE self, VALUE in_lo_desc, VALUE in_len)
{
	int ret;
  PGconn *conn = pg_get_pgconn(self);
	int len = NUM2INT(in_len);
	int lo_desc = NUM2INT(in_lo_desc);
	VALUE str;
	char *buffer;

	if (len < 0)
		pg_raise_conn_error( rb_ePGerror, self, "negative length %d given", len);

	buffer = ALLOC_N(char, len);

	BLOCKING_BEGIN(conn)
		ret = lo_read(conn, lo_desc, buffer, len);
	BLOCKING_END(conn)

	if(ret < 0)
		pg_raise_conn_error( rb_ePGerror, self, "lo_read failed");

	if(ret == 0) {
		xfree(buffer);
		return Qnil;
	}

	str = rb_str_new(buffer, ret);
	xfree(buffer);

	return str;
}


  








  

    #loseek(lo_desc, offset, whence)  ⇒ Integer     Also known as: #lo_lseek, #lolseek, #lo_seek
  



  

    

Move the large object pointer lo_desc to offset offset. Valid values for whence are SEEK_SET, SEEK_CUR, and SEEK_END. (Or 0, 1, or 2.)


  



  [ GitHub ]


  

  


# File 'ext/pg_connection.c', line 4110



static VALUE
pgconn_lolseek(VALUE self, VALUE in_lo_desc, VALUE offset, VALUE whence)
{
	PGconn *conn = pg_get_pgconn(self);
	int lo_desc = NUM2INT(in_lo_desc);
	int ret;

	BLOCKING_BEGIN(conn)
		ret = lo_lseek(conn, lo_desc, NUM2INT(offset), NUM2INT(whence));
	BLOCKING_END(conn)

	if(ret < 0) {
		pg_raise_conn_error( rb_ePGerror, self, "lo_lseek failed");
	}

	return INT2FIX(ret);
}


  








  

    #lotell(lo_desc)  ⇒ Integer     Also known as: #lo_tell
  



  

    

Returns the current position of the large object lo_desc.


  



  [ GitHub ]


  

  


# File 'ext/pg_connection.c', line 4134



static VALUE
pgconn_lotell(VALUE self, VALUE in_lo_desc)
{
	int position;
	PGconn *conn = pg_get_pgconn(self);
	int lo_desc = NUM2INT(in_lo_desc);

	BLOCKING_BEGIN(conn)
		position = lo_tell(conn, lo_desc);
	BLOCKING_END(conn)

	if(position < 0)
		pg_raise_conn_error( rb_ePGerror, self, "lo_tell failed");

	return INT2FIX(position);
}


  








  

    #lotruncate(lo_desc, len)  ⇒ nil     Also known as: #lo_truncate
  



  

    

Truncates the large object lo_desc to size len.


  



  [ GitHub ]


  

  


# File 'ext/pg_connection.c', line 4157



static VALUE
pgconn_lotruncate(VALUE self, VALUE in_lo_desc, VALUE in_len)
{
	PGconn *conn = pg_get_pgconn(self);
	int lo_desc = NUM2INT(in_lo_desc);
	size_t len = NUM2INT(in_len);
	int ret;

	BLOCKING_BEGIN(conn)
		ret = lo_truncate(conn,lo_desc,len);
	BLOCKING_END(conn)

	if(ret < 0)
		pg_raise_conn_error( rb_ePGerror, self, "lo_truncate failed");

	return Qnil;
}


  










  

    #lowrite(lo_desc, buffer)  ⇒ Integer     Also known as: #lo_write
  



  

    

Writes the string buffer to the large object lo_desc. Returns the number of bytes written.


  



  [ GitHub ]


  

  


# File 'ext/pg_connection.c', line 4037



static VALUE
pgconn_lowrite(VALUE self, VALUE in_lo_desc, VALUE buffer)
{
	int n;
	PGconn *conn = pg_get_pgconn(self);
	int fd = NUM2INT(in_lo_desc);

	Check_Type(buffer, T_STRING);

	if( RSTRING_LEN(buffer) < 0) {
		pg_raise_conn_error( rb_ePGerror, self, "write buffer zero string");
	}
	BLOCKING_BEGIN(conn)
		n = lo_write(conn, fd, StringValuePtr(buffer),
				RSTRING_LEN(buffer));
	BLOCKING_END(conn)

	if(n < 0) {
		pg_raise_conn_error( rb_ePGerror, self, "lo_write failed: %s", PQerrorMessage(conn));
	}

	return INT2FIX(n);
}


  








  

    #make_empty_pgresult(status)  ⇒ PG::Result   



  

    

Constructs and empty Result with status status. status may be one of:


  • 

    PGRES_EMPTY_QUERY
    

  • 

    PGRES_COMMAND_OK
    

  • 

    PGRES_TUPLES_OK
    

  • 

    PGRES_COPY_OUT
    

  • 

    PGRES_COPY_IN
    

  • 

    PGRES_BAD_RESPONSE
    

  • 

    PGRES_NONFATAL_ERROR
    

  • 

    PGRES_FATAL_ERROR
    

  • 

    PGRES_COPY_BOTH
    

  • 

    PGRES_SINGLE_TUPLE
    

  • 

    PGRES_TUPLES_CHUNK
    

  • 

    PGRES_PIPELINE_SYNC
    

  • 

    PGRES_PIPELINE_ABORTED
    



  



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# File 'ext/pg_connection.c', line 1623



static VALUE
pgconn_make_empty_pgresult(VALUE self, VALUE status)
{
	PGresult *result;
	VALUE rb_pgresult;
	PGconn *conn = pg_get_pgconn(self);
	result = PQmakeEmptyPGresult(conn, NUM2INT(status));
	rb_pgresult = pg_new_result(result, self);
	pg_result_check(rb_pgresult);
	return rb_pgresult;
}


  








  

    #notifies    



  

    

Returns a hash of the unprocessed notifications. If there is no unprocessed notifier, it returns nil.


  



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# File 'ext/pg_connection.c', line 2346



static VALUE
pgconn_notifies(VALUE self)
{
	t_pg_connection *this = pg_get_connection_safe( self );
	PGnotify *notification;
	VALUE hash;
	VALUE sym_relname, sym_be_pid, sym_extra;
	VALUE relname, be_pid, extra;

	sym_relname = ID2SYM(rb_intern("relname"));
	sym_be_pid = ID2SYM(rb_intern("be_pid"));
	sym_extra = ID2SYM(rb_intern("extra"));

	notification = gvl_PQnotifies(this->pgconn);
	if (notification == NULL) {
		return Qnil;
	}

	hash = rb_hash_new();
	relname = rb_str_new2(notification->relname);
	be_pid = INT2NUM(notification->be_pid);
	extra = rb_str_new2(notification->extra);
	PG_ENCODING_SET_NOCHECK( relname, this->enc_idx );
	PG_ENCODING_SET_NOCHECK( extra, this->enc_idx );

	rb_hash_aset(hash, sym_relname, relname);
	rb_hash_aset(hash, sym_be_pid, be_pid);
	rb_hash_aset(hash, sym_extra, extra);

	PQfreemem(notification);
	return hash;
}


  








  

    #notifies_wait([ timeout ]) {|event, pid, payload| ... } ⇒ String     Also known as: #wait_for_notify
  



  

    

Blocks while waiting for notification(s), or until the optional timeout is reached, whichever comes first.  timeout is measured in seconds and can be fractional.



Returns nil if timeout is reached, the name of the NOTIFY event otherwise. If used in block form, passes the name of the NOTIFY event, the generating pid and the optional payload string into the block.


  



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# File 'ext/pg_connection.c', line 2632



static VALUE
pgconn_wait_for_notify(int argc, VALUE *argv, VALUE self)
{
	t_pg_connection *this = pg_get_connection_safe( self );
	PGnotify *pnotification;
	struct timeval timeout;
	struct timeval *ptimeout = NULL;
	VALUE timeout_in = Qnil, relname = Qnil, be_pid = Qnil, extra = Qnil;
	double timeout_sec;

	rb_scan_args( argc, argv, "01", &timeout_in );

	if ( RTEST(timeout_in) ) {
		timeout_sec = NUM2DBL( timeout_in );
		timeout.tv_sec = (time_t)timeout_sec;
		timeout.tv_usec = (suseconds_t)( (timeout_sec - (long)timeout_sec) * 1e6 );
		ptimeout = &timeout;
	}

	pnotification = (PGnotify*) wait_socket_readable( self, ptimeout, notify_readable);

	/* Return nil if the select timed out */
	if ( !pnotification ) return Qnil;

	relname = rb_str_new2( pnotification->relname );
	PG_ENCODING_SET_NOCHECK( relname, this->enc_idx );
	be_pid = INT2NUM( pnotification->be_pid );
	if ( *pnotification->extra ) {
		extra = rb_str_new2( pnotification->extra );
		PG_ENCODING_SET_NOCHECK( extra, this->enc_idx );
	}
	PQfreemem( pnotification );

	if ( rb_block_given_p() )
		rb_yield_values( 3, relname, be_pid, extra );

	return relname;
}


  








  

    #options    



  

    

Returns backend option string.


  



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# File 'ext/pg_connection.c', line 747



static VALUE
pgconn_options(VALUE self)
{
	char *options = PQoptions(pg_get_pgconn(self));
	if (!options) return Qnil;
	return rb_str_new2(options);
}


  








  

    #parameter_status(param_name)  ⇒ String   



  

    

Returns the setting of parameter param_name, where param_name is one of


  • 

    #server_version
    

  • 

    server_encoding
    

  • 

    client_encoding
    

  • 

    is_superuser
    

  • 

    session_authorization
    

  • 

    DateStyle
    

  • 

    TimeZone
    

  • 

    integer_datetimes
    

  • 

    standard_conforming_strings
    




Returns nil if the value of the parameter is not known.


  



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# File 'ext/pg_connection.c', line 834



static VALUE
pgconn_parameter_status(VALUE self, VALUE param_name)
{
	const char *ret = PQparameterStatus(pg_get_pgconn(self), StringValueCStr(param_name));
	if(ret == NULL)
		return Qnil;
	else
		return rb_str_new2(ret);
}


  








  

    #pass    



  

    

Returns the authenticated password.


  



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# File 'ext/pg_connection.c', line 660



static VALUE
pgconn_pass(VALUE self)
{
	char *user = PQpass(pg_get_pgconn(self));
	if (!user) return Qnil;
	return rb_str_new2(user);
}


  








  

    #pipeline_status  ⇒ Integer   



  

    

Returns the current pipeline mode status of the libpq connection.



PQpipelineStatus can return one of the following values:


  • 

    PQ_PIPELINE_ON - The libpq connection is in pipeline mode.
    

  • 

    PQ_PIPELINE_OFF - The libpq connection is not in pipeline mode.
    

  • 

    PQ_PIPELINE_ABORTED - The libpq connection is in pipeline mode and an error occurred while processing the current pipeline. The aborted flag is cleared when PQgetResult returns a result of type PGRES_PIPELINE_SYNC.
    




Available since PostgreSQL-14


  



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# File 'ext/pg_connection.c', line 3751



static VALUE
pgconn_pipeline_status(VALUE self)
{
	int res = PQpipelineStatus(pg_get_pgconn(self));
	return INT2FIX(res);
}


  








  

    #pipeline_sync      Also known as: #async_pipeline_sync
  



  

    

Marks a synchronization point in a pipeline by sending a sync message and flushing the send buffer. This serves as the delimiter of an implicit transaction and an error recovery point.



See enter_pipeline_mode



Raises Error if the connection is not in pipeline mode or sending a sync message failed.



Available since PostgreSQL-14


  



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# File 'lib/pg/connection.rb', line 551



def pipeline_sync(*args)
	send_pipeline_sync(*args)
	flush
end


  








  

    #port    



  

    

Returns the connected server port number.


  



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# File 'ext/pg_connection.c', line 719



static VALUE
pgconn_port(VALUE self)
{
	char* port = PQport(pg_get_pgconn(self));
	if (!port || port[0] == '\0')
		return INT2NUM(DEF_PGPORT);
	else
		return INT2NUM(atoi(port));
}


  








  

    #prepare(stmt_name, sql [, param_types ] )  ⇒ PG::Result     Also known as: #async_prepare
  



  

    

Prepares statement sql with name name to be executed later. Returns a Result instance on success. On failure, it raises a Error.



param_types is an optional parameter to specify the Oids of the types of the parameters.



If the types are not specified, they will be inferred by PostgreSQL. Instead of specifying type oids, it’s recommended to simply add explicit casts in the query to ensure that the right type is used.



For example: “SELECT $1::int”



PostgreSQL bind parameters are represented as $1, $2, $3, etc., inside the SQL query.



See also corresponding libpq function.


  



  [ GitHub ]


  

  


# File 'ext/pg_connection.c', line 3500



static VALUE
pgconn_async_prepare(int argc, VALUE *argv, VALUE self)
{
	VALUE rb_pgresult = Qnil;

	pgconn_discard_results( self );
	pgconn_send_prepare( argc, argv, self );
	rb_pgresult = pgconn_async_get_last_result( self );

	if ( rb_block_given_p() ) {
		return rb_ensure( rb_yield, rb_pgresult, pg_result_clear, rb_pgresult );
	}
	return rb_pgresult;
}


  








  

    #protocol_version  ⇒ Integer   



  

    

The 3.0 protocol will normally be used when communicating with PostgreSQL 7.4 or later servers; pre-7.4 servers support only protocol 2.0. (Protocol 1.0 is obsolete and not supported by libpq.)


  



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# File 'ext/pg_connection.c', line 852



static VALUE
pgconn_protocol_version(VALUE self)
{
	return INT2NUM(PQprotocolVersion(pg_get_pgconn(self)));
}


  








  

    #put_copy_data(buffer [, encoder] )  ⇒ Boolean     Also known as: #async_put_copy_data
  



  

    

Transmits buffer as copy data to the server. Returns true if the data was sent, false if it was not sent (false is only possible if the connection is in nonblocking mode, and this command would block).



encoder can be a Coder derivation (typically TextEncoder::CopyRow). This encodes the data fields given as buffer from an Array of Strings to PostgreSQL’s COPY text format inclusive proper escaping. Optionally the encoder can type cast the fields from various Ruby types in one step, if PG::TextEncoder::CopyRow#type_map is set accordingly.



Raises an exception if an error occurs.



See also #copy_data.


  



  [ GitHub ]


  

  


# File 'lib/pg/connection.rb', line 500



def put_copy_data(buffer, encoder=nil)
	# sync_put_copy_data does a non-blocking attempt to flush data.
	until res=sync_put_copy_data(buffer, encoder)
		# It didn't flush immediately and allocation of more buffering memory failed.
		# Wait for all data sent by doing a blocking flush.
		res = flush
	end

	# And do a blocking flush every 100 calls.
	# This is to avoid memory bloat, when sending the data is slower than calls to put_copy_data happen.
	if (@calls_to_put_copy_data += 1) > 100
		@calls_to_put_copy_data = 0
		res = flush
	end
	res
end


  








  

    #put_copy_end([ error_message ])  ⇒ Boolean     Also known as: #async_put_copy_end
  



  

    

Sends end-of-data indication to the server.



error_message is an optional parameter, and if set, forces the COPY command to fail with the string error_message.



Returns true if the end-of-data was sent, #false* if it was not sent (false is only possible if the connection is in nonblocking mode, and this command would block).


  



  [ GitHub ]


  

  


# File 'lib/pg/connection.rb', line 530



def put_copy_end(*args)
	until sync_put_copy_end(*args)
		flush
	end
	@calls_to_put_copy_data = 0
	flush
end


  








  

    

      #quote_ident(str)  ⇒ String 
      #quote_ident(array)  ⇒ String 
      #quote_ident(str)  ⇒ String 
      #quote_ident(array)  ⇒ String 
    

  



  

    

Alias for .quote_ident.


  





  








  

    #reset      Also known as: #async_reset
  



  

    

Resets the backend connection. This method closes the backend connection and tries to re-connect.


  



  [ GitHub ]


  

  


# File 'lib/pg/connection.rb', line 591



def reset
	# Use connection options from PG::Connection.new to reconnect with the same options but with renewed DNS resolution.
	# Use conninfo_hash as a fallback when connect_start was used to create the connection object.
	iopts = @iopts_for_reset || conninfo_hash.compact
	if iopts[:host] && !iopts[:host].empty? && PG.library_version >= 100000
		iopts = self.class.send(:resolve_hosts, iopts)
	end
	conninfo = self.class.parse_connect_args( iopts );
	reset_start2(conninfo)
	async_connect_or_reset(:reset_poll)
	self
end


  








  

    #reset_poll  ⇒ Integer   



  

    

Checks the status of a connection reset operation. See .connect_start and #connect_poll for usage information and return values.


  



  [ GitHub ]


  

  


# File 'ext/pg_connection.c', line 614



static VALUE
pgconn_reset_poll(VALUE self)
{
	PostgresPollingStatusType status;

	pgconn_close_socket_io(self);
	status = gvl_PQresetPoll(pg_get_pgconn(self));

	return INT2FIX((int)status);
}


  








  

    #reset_start  ⇒ nil   



  

    

Initiate a connection reset in a nonblocking manner. This will close the current connection and attempt to reconnect using the same connection parameters. Use #reset_poll to check the status of the connection reset.


  



  [ GitHub ]


  

  


# File 'ext/pg_connection.c', line 597



static VALUE
pgconn_reset_start(VALUE self)
{
	pgconn_close_socket_io( self );
	if(gvl_PQresetStart(pg_get_pgconn(self)) == 0)
		pg_raise_conn_error( rb_eUnableToSend, self, "reset has failed");
	return Qnil;
}


  








  

    #reset_start2(conninfo)   (private)
  

  [ GitHub ]


  

  


# File 'ext/pg_connection.c', line 566



static VALUE
pgconn_reset_start2( VALUE self, VALUE conninfo )
{
	t_pg_connection *this = pg_get_connection( self );

	/* Close old connection */
	pgconn_close_socket_io( self );
	PQfinish( this->pgconn );

	/* Start new connection */
	this->pgconn = gvl_PQconnectStart( StringValueCStr(conninfo) );

	if( this->pgconn == NULL )
		rb_raise(rb_ePGerror, "PQconnectStart() unable to allocate PGconn structure");

	if ( PQstatus(this->pgconn) == CONNECTION_BAD )
		pg_raise_conn_error( rb_eConnectionBad, self, "%s", PQerrorMessage(this->pgconn));

	return Qnil;
}


  








  

    #send_describe_portal(portal_name)  ⇒ nil   



  

    

Asynchronously send command to the server. Does not block. Use in combination with conn.get_result.


  



  [ GitHub ]


  

  


# File 'ext/pg_connection.c', line 2180



static VALUE
pgconn_send_describe_portal(VALUE self, VALUE portal)
{
	return pgconn_send_describe_close_prepared_portal(
		self, portal, gvl_PQsendDescribePortal,
		"PQsendDescribePortal");
}


  








  

    #send_describe_prepared(statement_name)  ⇒ nil   



  

    

Asynchronously send command to the server. Does not block. Use in combination with conn.get_result.


  



  [ GitHub ]


  

  


# File 'ext/pg_connection.c', line 2164



static VALUE
pgconn_send_describe_prepared(VALUE self, VALUE stmt_name)
{
	return pgconn_send_describe_close_prepared_portal(
		self, stmt_name, gvl_PQsendDescribePrepared,
		"PQsendDescribePrepared");
}


  








  

    #send_flush_request  ⇒ nil   



  

    

Sends a request for the server to flush its output buffer.



The server flushes its output buffer automatically as a result of #pipeline_sync being called, or on any request when not in pipeline mode. This function is useful to cause the server to flush its output buffer in pipeline mode without establishing a synchronization point. Note that the request is not itself flushed to the server automatically; use #flush if necessary.



Available since PostgreSQL-14


  



  [ GitHub ]


  

  


# File 'ext/pg_connection.c', line 3866



static VALUE
pgconn_send_flush_request(VALUE self)
{
	PGconn *conn = pg_get_pgconn(self);
	int res = PQsendFlushRequest(conn);
	if( res != 1 )
		pg_raise_conn_error( rb_ePGerror, self, "%s", PQerrorMessage(conn));

	return Qnil;
}


  








  

    #send_pipeline_sync  ⇒ nil   



  

    

Marks a synchronization point in a pipeline by sending a sync message without flushing the send buffer.



This serves as the delimiter of an implicit transaction and an error recovery point. Raises Error if the connection is not in pipeline mode or sending a sync message failed. Note that the message is not itself flushed to the server automatically; use flush if necessary.



Available since PostgreSQL-17


  



  [ GitHub ]


  

  


# File 'ext/pg_connection.c', line 3841



static VALUE
pgconn_send_pipeline_sync(VALUE self)
{
	PGconn *conn = pg_get_pgconn(self);
	int res = gvl_PQsendPipelineSync(conn);
	if( res != 1 )
		pg_raise_conn_error( rb_ePGerror, self, "%s", PQerrorMessage(conn));

	return Qnil;
}


  








  

    #send_prepare(stmt_name, sql [, param_types ] )  ⇒ nil   



  

    

Prepares statement sql with name name to be executed later. Sends prepare command asynchronously, and returns immediately. On failure, it raises a Error.



param_types is an optional parameter to specify the Oids of the types of the parameters.



If the types are not specified, they will be inferred by PostgreSQL. Instead of specifying type oids, it’s recommended to simply add explicit casts in the query to ensure that the right type is used.



For example: “SELECT $1::int”



PostgreSQL bind parameters are represented as $1, $2, $3, etc., inside the SQL query.


  



  [ GitHub ]


  

  


# File 'ext/pg_connection.c', line 2036



static VALUE
pgconn_send_prepare(int argc, VALUE *argv, VALUE self)
{
	t_pg_connection *this = pg_get_connection_safe( self );
	int result;
	VALUE name, command, in_paramtypes;
	VALUE param;
	int i = 0;
	int nParams = 0;
	Oid *paramTypes = NULL;
	const char *name_cstr;
	const char *command_cstr;
	int enc_idx = this->enc_idx;

	rb_scan_args(argc, argv, "21", &name, &command, &in_paramtypes);
	name_cstr = pg_cstr_enc(name, enc_idx);
	command_cstr = pg_cstr_enc(command, enc_idx);

	if(! NIL_P(in_paramtypes)) {
		Check_Type(in_paramtypes, T_ARRAY);
		nParams = (int)RARRAY_LEN(in_paramtypes);
		paramTypes = ALLOC_N(Oid, nParams);
		for(i = 0; i < nParams; i++) {
			param = rb_ary_entry(in_paramtypes, i);
			if(param == Qnil)
				paramTypes[i] = 0;
			else
				paramTypes[i] = NUM2UINT(param);
		}
	}
	result = gvl_PQsendPrepare(this->pgconn, name_cstr, command_cstr, nParams, paramTypes);

	xfree(paramTypes);

	if(result == 0) {
		pg_raise_conn_error( rb_eUnableToSend, self, "PQsendPrepare %s", PQerrorMessage(this->pgconn));
	}
	pgconn_wait_for_flush( self );
	return Qnil;
}


  








  

    #send_query(sql)  ⇒ nil   



  

    

Sends SQL query request specified by sql to PostgreSQL for asynchronous processing, and immediately returns. On failure, it raises a Error.



For backward compatibility, if you pass more than one parameter to this method, it will call #send_query_params for you. New code should explicitly use #send_query_params if argument placeholders are used.


  



  [ GitHub ]


  

  


# File 'ext/pg_connection.c', line 1927



static VALUE
pgconn_send_query(int argc, VALUE *argv, VALUE self)
{
	t_pg_connection *this = pg_get_connection_safe( self );

	/* If called with no or nil parameters, use PQexec for compatibility */
	if ( argc == 1 || (argc >= 2 && argc <= 4 && NIL_P(argv[1]) )) {
		if(gvl_PQsendQuery(this->pgconn, pg_cstr_enc(argv[0], this->enc_idx)) == 0)
			pg_raise_conn_error( rb_eUnableToSend, self, "PQsendQuery %s", PQerrorMessage(this->pgconn));

		pgconn_wait_for_flush( self );
		return Qnil;
	}

	pg_deprecated(2, ("forwarding async_exec to async_exec_params and send_query to send_query_params is deprecated"));

	/* If called with parameters, and optionally result_format,
	 * use PQsendQueryParams
	 */
	return pgconn_send_query_params( argc, argv, self);
}


  








  

    #send_query_params(sql, params [, result_format [, type_map ]] )  ⇒ nil   



  

    

Sends SQL query request specified by sql to PostgreSQL for asynchronous processing, and immediately returns. On failure, it raises a Error.



params is an array of the bind parameters for the SQL query. Each element of the params array may be either:



a hash of the form:
  {:value  => String (value of bind parameter)
   :type   => Integer (oid of type of bind parameter)
   :format => Integer (0 for text, 1 for binary)
  }
or, it may be a String. If it is a string, that is equivalent to the hash:
  { :value => <string value>, :type => 0, :format => 0 }



PostgreSQL bind parameters are represented as $1, $2, $3, etc., inside the SQL query. The 0th element of the params array is bound to $1, the 1st element is bound to $2, etc. nil is treated as NULL.



If the types are not specified, they will be inferred by PostgreSQL. Instead of specifying type oids, it’s recommended to simply add explicit casts in the query to ensure that the right type is used.



For example: “SELECT $1::int”



The optional result_format should be 0 for text results, 1 for binary.



type_map can be a TypeMap derivation (such as BasicTypeMapForQueries). This will type cast the params from various Ruby types before transmission based on the encoders defined by the type map. When a type encoder is used the format and oid of a given bind parameter are retrieved from the encoder instead out of the hash form described above.


  



  [ GitHub ]


  

  


# File 'ext/pg_connection.c', line 1987



static VALUE
pgconn_send_query_params(int argc, VALUE *argv, VALUE self)
{
	t_pg_connection *this = pg_get_connection_safe( self );
	int result;
	VALUE command, in_res_fmt;
	int nParams;
	int resultFormat;
	struct query_params_data paramsData = { this->enc_idx };

	rb_scan_args(argc, argv, "22", &command, &paramsData.params, &in_res_fmt, &paramsData.typemap);
	paramsData.with_types = 1;

	pgconn_query_assign_typemap( self, &paramsData );
	resultFormat = NIL_P(in_res_fmt) ? 0 : NUM2INT(in_res_fmt);
	nParams = alloc_query_params( &paramsData );

	result = gvl_PQsendQueryParams(this->pgconn, pg_cstr_enc(command, paramsData.enc_idx), nParams, paramsData.types,
		(const char * const *)paramsData.values, paramsData.lengths, paramsData.formats, resultFormat);

	free_query_params( &paramsData );

	if(result == 0)
		pg_raise_conn_error( rb_eUnableToSend, self, "PQsendQueryParams %s", PQerrorMessage(this->pgconn));

	pgconn_wait_for_flush( self );
	return Qnil;
}


  








  

    

      #send_query_prepared(statement_name [, params, result_format[, type_map ]] )  
      #-  
    

  



  

    

Execute prepared named statement specified by statement_name asynchronously, and returns immediately. On failure, it raises a Error.



params is an array of the optional bind parameters for the SQL query. Each element of the params array may be either:



a hash of the form:
  {:value  => String (value of bind parameter)
   :format => Integer (0 for text, 1 for binary)
  }
or, it may be a String. If it is a string, that is equivalent to the hash:
  { :value => <string value>, :format => 0 }



PostgreSQL bind parameters are represented as $1, $2, $3, etc., inside the SQL query. The 0th element of the params array is bound to $1, the 1st element is bound to $2, etc. nil is treated as NULL.



The optional result_format should be 0 for text results, 1 for binary.



type_map can be a TypeMap derivation (such as BasicTypeMapForQueries). This will type cast the params from various Ruby types before transmission based on the encoders defined by the type map. When a type encoder is used the format and oid of a given bind parameter are retrieved from the encoder instead out of the hash form described above.


  





  


  [ GitHub ]


  

  


# File 'ext/pg_connection.c', line 2109



static VALUE
pgconn_send_query_prepared(int argc, VALUE *argv, VALUE self)
{
	t_pg_connection *this = pg_get_connection_safe( self );
	int result;
	VALUE name, in_res_fmt;
	int nParams;
	int resultFormat;
	struct query_params_data paramsData = { this->enc_idx };

	rb_scan_args(argc, argv, "13", &name, &paramsData.params, &in_res_fmt, &paramsData.typemap);
	paramsData.with_types = 0;

	if(NIL_P(paramsData.params)) {
		paramsData.params = rb_ary_new2(0);
	}
	pgconn_query_assign_typemap( self, &paramsData );

	resultFormat = NIL_P(in_res_fmt) ? 0 : NUM2INT(in_res_fmt);
	nParams = alloc_query_params( &paramsData );

	result = gvl_PQsendQueryPrepared(this->pgconn, pg_cstr_enc(name, paramsData.enc_idx), nParams,
		(const char * const *)paramsData.values, paramsData.lengths, paramsData.formats,
		resultFormat);

	free_query_params( &paramsData );

	if(result == 0)
		pg_raise_conn_error( rb_eUnableToSend, self, "PQsendQueryPrepared %s", PQerrorMessage(this->pgconn));

	pgconn_wait_for_flush( self );
	return Qnil;
}


  








  

    #server_version  ⇒ Integer   



  

    

The number is formed by converting the major, minor, and revision numbers into two-decimal-digit numbers and appending them together. For example, version 7.4.2 will be returned as 70402, and version 8.1 will be returned as 80100 (leading zeroes are not shown). Zero is returned if the connection is bad.


  



  [ GitHub ]


  

  


# File 'ext/pg_connection.c', line 869



static VALUE
pgconn_server_version(VALUE self)
{
	return INT2NUM(PQserverVersion(pg_get_pgconn(self)));
}


  








  

    #set_chunked_rows_mode  ⇒ self   



  

    

Select chunked mode for the currently-executing query.



This function is similar to set_single_row_mode, except that it specifies retrieval of up to chunk_size rows per PGresult, not necessarily just one row. This function can only be called immediately after send_query or one of its sibling functions, before any other operation on the connection such as consume_input or get_result. If called at the correct time, the function activates chunked mode for the current query. Otherwise the mode stays unchanged and the function raises an error. In any case, the mode reverts to normal after completion of the current query.



Example:



conn.send_query( "your SQL command" )
conn.set_chunked_rows_mode(10)
loop do
  res = conn.get_result or break
  res.check
  res.each do |row|
    # do something with the received max. 10 rows
  end
end



Available since PostgreSQL-17


  



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# File 'ext/pg_connection.c', line 1899



static VALUE
pgconn_set_chunked_rows_mode(VALUE self, VALUE chunk_size)
{
	PGconn *conn = pg_get_pgconn(self);

	rb_check_frozen(self);
	if( PQsetChunkedRowsMode(conn, NUM2INT(chunk_size)) == 0 )
		pg_raise_conn_error( rb_ePGerror, self, "PQsetChunkedRowsMode %s", PQerrorMessage(conn));

	return self;
}


  








  

    

      #client_encoding=(encoding)  
      #set_client_encoding(encoding)  
    

  



  

    

Alias for #client_encoding=.


  





  








  

    #set_default_encoding  ⇒ Encoding   



  

    

If Ruby has its Encoding.default_internal set, set PostgreSQL’s client_encoding to match. Returns the new Encoding, or nil if the default internal encoding wasn’t set.


  



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# File 'ext/pg_connection.c', line 4374



static VALUE
pgconn_set_default_encoding( VALUE self )
{
	PGconn *conn = pg_get_pgconn( self );
	rb_encoding *rb_enc;

	rb_check_frozen(self);
	if (( rb_enc = rb_default_internal_encoding() )) {
		rb_encoding * conn_encoding = pg_conn_enc_get( conn );

		/* Don't set the server encoding, if it's unnecessary.
		 * This is important for connection proxies, who disallow configuration settings.
		 */
		if ( conn_encoding != rb_enc ) {
			const char *encname = pg_get_rb_encoding_as_pg_encoding( rb_enc );
			if ( pgconn_set_client_encoding_async(self, rb_str_new_cstr(encname)) != 0 )
				rb_warning( "Failed to set the default_internal encoding to %s: '%s'",
								encname, PQerrorMessage(conn) );
		}
		pgconn_set_internal_encoding_index( self );
		return rb_enc_from_encoding( rb_enc );
	} else {
		pgconn_set_internal_encoding_index( self );
		return Qnil;
	}
}


  








  

    #set_error_context_visibility(context_visibility)  ⇒ Integer   



  

    

Sets connection’s context display mode to context_visibility and returns the previous setting. Available settings are:


  • 

    PQSHOW_CONTEXT_NEVER
    

  • 

    PQSHOW_CONTEXT_ERRORS
    

  • 

    PQSHOW_CONTEXT_ALWAYS
    




This mode controls whether the CONTEXT field is included in messages (unless the verbosity setting is TERSE, in which case CONTEXT is never shown). The NEVER mode never includes CONTEXT, while ALWAYS always includes it if available. In ERRORS mode (the default), CONTEXT fields are included only for error messages, not for notices and warnings.



Changing this mode does not affect the messages available from already-existing Result objects, only subsequently-created ones. (But see Result#verbose_error_message if you want to print a previous error with a different display mode.)



See also corresponding libpq function.


  



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# File 'ext/pg_connection.c', line 2834



static VALUE
pgconn_set_error_context_visibility(VALUE self, VALUE in_context_visibility)
{
	PGconn *conn = pg_get_pgconn(self);
	PGContextVisibility context_visibility = NUM2INT(in_context_visibility);
	return INT2FIX(PQsetErrorContextVisibility(conn, context_visibility));
}


  








  

    #set_error_verbosity(verbosity)  ⇒ Integer   



  

    

Sets connection’s verbosity to verbosity and returns the previous setting. Available settings are:


  • 

    PQERRORS_TERSE
    

  • 

    PQERRORS_DEFAULT
    

  • 

    PQERRORS_VERBOSE
    

  • 

    PQERRORS_SQLSTATE
    




Changing the verbosity does not affect the messages available from already-existing Result objects, only subsequently-created ones. (But see Result#verbose_error_message if you want to print a previous error with a different verbosity.)



See also corresponding libpq function.


  



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# File 'ext/pg_connection.c', line 2806



static VALUE
pgconn_set_error_verbosity(VALUE self, VALUE in_verbosity)
{
	PGconn *conn = pg_get_pgconn(self);
	PGVerbosity verbosity = NUM2INT(in_verbosity);
	return INT2FIX(PQsetErrorVerbosity(conn, verbosity));
}


  








  

    #set_notice_processor {|message| ... } ⇒ Proc   



  

    

See #set_notice_receiver for the description of what this and the notice_processor methods do.



This function takes a new block to act as the notice processor and returns the Proc object previously set, or nil if it was previously the default. The block should accept a single String object.



If you pass no arguments, it will reset the handler to the default.


  



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# File 'ext/pg_connection.c', line 3015



static VALUE
pgconn_set_notice_processor(VALUE self)
{
	VALUE proc, old_proc;
	t_pg_connection *this = pg_get_connection_safe( self );

	rb_check_frozen(self);
	/* If default_notice_processor is unset, assume that the current
	 * notice processor is the default, and save it to a global variable.
	 * This should not be a problem because the default processor is
	 * always the same, so won't vary among connections.
	 */
	if(this->default_notice_processor == NULL)
		this->default_notice_processor = PQsetNoticeProcessor(this->pgconn, NULL, NULL);

	old_proc = this->notice_processor;
	if( rb_block_given_p() ) {
		proc = rb_block_proc();
		PQsetNoticeProcessor(this->pgconn, gvl_notice_processor_proxy, (void *)self);
	} else {
		/* if no block is given, set back to default */
		proc = Qnil;
		PQsetNoticeProcessor(this->pgconn, this->default_notice_processor, NULL);
	}

	RB_OBJ_WRITE(self, &this->notice_processor, proc);
	return old_proc;
}


  








  

    #set_notice_receiver {|result| ... } ⇒ Proc   



  

    

Notice and warning messages generated by the server are not returned by the query execution functions, since they do not imply failure of the query. Instead they are passed to a notice handling function, and execution continues normally after the handler returns. The default notice handling function prints the message on stderr, but the application can override this behavior by supplying its own handling function.



For historical reasons, there are two levels of notice handling, called the notice receiver and notice processor. The default behavior is for the notice receiver to format the notice and pass a string to the notice processor for printing. However, an application that chooses to provide its own notice receiver will typically ignore the notice processor layer and just do all the work in the notice receiver.



This function takes a new block to act as the handler, which should accept a single parameter that will be a Result object, and returns the Proc object previously set, or nil if it was previously the default.



If you pass no arguments, it will reset the handler to the default.



Note: The result passed to the block should not be used outside of the block, since the corresponding C object could be freed after the block finishes.


  



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# File 'ext/pg_connection.c', line 2954



static VALUE
pgconn_set_notice_receiver(VALUE self)
{
	VALUE proc, old_proc;
	t_pg_connection *this = pg_get_connection_safe( self );

	rb_check_frozen(self);
	/* If default_notice_receiver is unset, assume that the current
	 * notice receiver is the default, and save it to a global variable.
	 * This should not be a problem because the default receiver is
	 * always the same, so won't vary among connections.
	 */
	if(this->default_notice_receiver == NULL)
		this->default_notice_receiver = PQsetNoticeReceiver(this->pgconn, NULL, NULL);

	old_proc = this->notice_receiver;
	if( rb_block_given_p() ) {
		proc = rb_block_proc();
		PQsetNoticeReceiver(this->pgconn, gvl_notice_receiver_proxy, (void *)self);
	} else {
		/* if no block is given, set back to default */
		proc = Qnil;
		PQsetNoticeReceiver(this->pgconn, this->default_notice_receiver, NULL);
	}

	RB_OBJ_WRITE(self, &this->notice_receiver, proc);
	return old_proc;
}


  








  

    #set_single_row_mode  ⇒ self   



  

    

To enter single-row mode, call this method immediately after a successful call of send_query (or a sibling function). This mode selection is effective only for the currently executing query. Then call #get_result repeatedly, until it returns nil.



Each (but the last) received Result has exactly one row and a Result#result_status of PGRES_SINGLE_TUPLE. The last Result has zero rows and is used to indicate a successful execution of the query. All of these Result objects will contain the same row description data (column names, types, etc) that an ordinary Result object for the query would have.



Caution: While processing a query, the server may return some rows and then encounter an error, causing the query to be aborted. Ordinarily, pg discards any such rows and reports only the error. But in single-row or chunked mode, some rows may have already been returned to the application. Hence, the application will see some PGRES_SINGLE_TUPLE or PGRES_TUPLES_CHUNK Result objects followed by a Error raised in get_result. For proper transactional behavior, the application must be designed to discard or undo whatever has been done with the previously-processed rows, if the query ultimately fails.



Example:



conn.send_query( "your SQL command" )
conn.set_single_row_mode
loop do
  res = conn.get_result or break
  res.check
  res.each do |row|
    # do something with the received row
  end
end


  



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# File 'ext/pg_connection.c', line 1861



static VALUE
pgconn_set_single_row_mode(VALUE self)
{
	PGconn *conn = pg_get_pgconn(self);

	rb_check_frozen(self);
	if( PQsetSingleRowMode(conn) == 0 )
		pg_raise_conn_error( rb_ePGerror, self, "PQsetSingleRowMode %s", PQerrorMessage(conn));

	return self;
}


  








  

    #setnonblocking(Boolean)  ⇒ nil     Also known as: #async_setnonblocking
  



  

    

Sets the nonblocking status of the connection. In the blocking state, calls to #send_query will block until the message is sent to the server, but will not wait for the query results. In the nonblocking state, calls to #send_query will return an error if the socket is not ready for writing. Note: This function does not affect #exec, because that function doesn’t return until the server has processed the query and returned the results.



Returns nil.


  



  [ GitHub ]


  

  


# File 'lib/pg/connection.rb', line 462



def setnonblocking(enabled)
	singleton_class.async_send_api = !enabled
	self.flush_data = !enabled
	sync_setnonblocking(true)
end


  








  

    #socket  ⇒ Integer   



  

    

This method is deprecated. Please use the more portable method #socket_io .



Returns the socket’s file descriptor for this connection. IO.for_fd() can be used to build a proper IO object to the socket. If you do so, you will likely also want to set autoclose=false on it to prevent Ruby from closing the socket to PostgreSQL if it goes out of scope. Alternatively, you can use #socket_io, which creates an IO that’s associated with the connection object itself, and so won’t go out of scope until the connection does.



Note: On Windows the file descriptor is not usable, since it can not be used to build a Ruby IO object.


  



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# File 'ext/pg_connection.c', line 909



static VALUE
pgconn_socket(VALUE self)
{
	int sd;
	pg_deprecated(4, ("conn.socket is deprecated and should be replaced by conn.socket_io"));

	if( (sd = PQsocket(pg_get_pgconn(self))) < 0)
		pg_raise_conn_error( rb_eConnectionBad, self, "PQsocket() can't get socket descriptor");

	return INT2NUM(sd);
}


  








  

    #socket_io  ⇒ IO   



  

    

Fetch an IO object created from the Connection’s underlying socket. This object can be used per socket_io.wait_readable, socket_io.wait_writable or for IO.select to wait for events while running asynchronous API calls. IO#wait_*able is Fiber.scheduler compatible in contrast to IO.select.



The IO object can change while the connection is established, but is memorized afterwards. So be sure not to cache the IO object, but repeat calling conn.socket_io instead.



Using this method also works on Windows in contrast to using #socket . It also avoids the problem of the underlying connection being closed by Ruby when an IO created using IO.for_fd(conn.socket) goes out of scope.


  



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# File 'ext/pg_connection.c', line 964



static VALUE
pgconn_socket_io(VALUE self)
{
	t_pg_connection *this = pg_get_connection_safe( self );

	if ( !RTEST(this->socket_io) ) {
		int sd;
		if( (sd = PQsocket(this->pgconn)) < 0){
			pg_raise_conn_error( rb_eConnectionBad, self, "PQsocket() can't get socket descriptor");
		}
		return pg_wrap_socket_io( sd, self, &this->socket_io, &this->ruby_sd);
	}

	return this->socket_io;
}


  








  

    #ssl_attribute(attribute_name)  ⇒ String   



  

    

Returns SSL-related information about the connection.



The list of available attributes varies depending on the SSL library being used, and the type of connection. If an attribute is not available, returns nil.



The following attributes are commonly available:


library



Name of the SSL implementation in use. (Currently, only “OpenSSL” is implemented)


protocol



SSL/TLS version in use. Common values are “SSLv2”, “SSLv3”, “TLSv1”, “TLSv1.1” and “TLSv1.2”, but an implementation may return other strings if some other protocol is used.


key_bits



Number of key bits used by the encryption algorithm.


cipher



A short name of the ciphersuite used, e.g. “DHE-RSA-DES-CBC3-SHA”. The names are specific to each SSL implementation.


compression



If SSL compression is in use, returns the name of the compression algorithm, or “on” if compression is used but the algorithm is not known. If compression is not in use, returns “off”.





See also #ssl_attribute_names and the corresponding libpq function.


  



  [ GitHub ]


  

  


# File 'ext/pg_connection.c', line 3702



static VALUE
pgconn_ssl_attribute(VALUE self, VALUE attribute_name)
{
	const char *p_attr;

	p_attr = PQsslAttribute(pg_get_pgconn(self), StringValueCStr(attribute_name));
	return p_attr ? rb_str_new_cstr(p_attr) : Qnil;
}


  








  

    #ssl_attribute_names  ⇒ Array<String>   



  

    

Return an array of SSL attribute names available.



See also #ssl_attribute


  



  [ GitHub ]


  

  


# File 'ext/pg_connection.c', line 3720



static VALUE
pgconn_ssl_attribute_names(VALUE self)
{
	int i;
	const char * const * p_list = PQsslAttributeNames(pg_get_pgconn(self));
	VALUE ary = rb_ary_new();

	for ( i = 0; p_list[i]; i++ ) {
		rb_ary_push( ary, rb_str_new_cstr( p_list[i] ));
	}
	return ary;
}


  








  

    #ssl_attributes  ⇒ Hash<String, String>   



  

    

Returns SSL-related information about the connection as key/value pairs



The available attributes varies depending on the SSL library being used, and the type of connection.



See also #ssl_attribute


  



  [ GitHub ]


  

  


# File 'lib/pg/connection.rb', line 368



def ssl_attributes
	ssl_attribute_names.each.with_object({}) do |n,h|
		h[n] = ssl_attribute(n)
	end
end


  








  

    #status    



  

    

Returns the status of the connection, which is one:



PG::Constants::CONNECTION_OK
PG::Constants::CONNECTION_BAD



… and other constants of kind PG::Constants::CONNECTION_*



This method returns the status of the last command from memory. It doesn’t do any socket access hence is not suitable to test the connectivity. See check_socket for a way to verify the socket state.



Example:



PG.constants.grep(/CONNECTION_/).find{|c| PG.const_get(c) == conn.status} # => :CONNECTION_OK


  



  [ GitHub ]


  

  


# File 'ext/pg_connection.c', line 793



static VALUE
pgconn_status(VALUE self)
{
	return INT2NUM(PQstatus(pg_get_pgconn(self)));
}


  








  

    #sync_cancel  
  



  

    

PostgreSQL-17+


  



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# File 'lib/pg/connection.rb', line 608



def sync_cancel
	cancon = PG::CancelConnection.new(self)
	cancon.sync_cancel
rescue PG::Error => err
	err.to_s
end


  








  

    #sync_close_portal(portal_name)  ⇒ PG::Result   



  

    

This function has the same behavior as #async_close_portal, but is implemented using the synchronous command processing API of libpq. See #async_exec for the differences between the two API variants. It’s not recommended to use explicit sync or async variants but #close_portal instead, unless you have a good reason to do so.



Available since PostgreSQL-17.


  



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# File 'ext/pg_connection.c', line 1596



static VALUE
pgconn_sync_close_portal(VALUE self, VALUE stmt_name)
{
	return pgconn_sync_describe_close_prepared_portal(self, stmt_name, gvl_PQclosePortal);
}


  








  

    #sync_close_prepared(stmt_name)  ⇒ PG::Result   



  

    

This function has the same behavior as #async_close_prepared, but is implemented using the synchronous command processing API of libpq. See #async_exec for the differences between the two API variants. It’s not recommended to use explicit sync or async variants but #close_prepared instead, unless you have a good reason to do so.



Available since PostgreSQL-17.


  



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# File 'ext/pg_connection.c', line 1580



static VALUE
pgconn_sync_close_prepared(VALUE self, VALUE stmt_name)
{
	return pgconn_sync_describe_close_prepared_portal(self, stmt_name, gvl_PQclosePrepared);
}


  








  

    #sync_describe_portal(portal_name)  ⇒ PG::Result   



  

    

This function has the same behavior as #async_describe_portal, but is implemented using the synchronous command processing API of libpq. See #async_exec for the differences between the two API variants. It’s not recommended to use explicit sync or async variants but #describe_portal instead, unless you have a good reason to do so.


  



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# File 'ext/pg_connection.c', line 1562



static VALUE
pgconn_sync_describe_portal(VALUE self, VALUE stmt_name)
{
	return pgconn_sync_describe_close_prepared_portal(self, stmt_name, gvl_PQdescribePortal);
}


  








  

    #sync_describe_prepared(statement_name)  ⇒ PG::Result   



  

    

This function has the same behavior as #async_describe_prepared, but is implemented using the synchronous command processing API of libpq. See #async_exec for the differences between the two API variants. It’s not recommended to use explicit sync or async variants but #describe_prepared instead, unless you have a good reason to do so.


  



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# File 'ext/pg_connection.c', line 1547



static VALUE
pgconn_sync_describe_prepared(VALUE self, VALUE stmt_name)
{
	return pgconn_sync_describe_close_prepared_portal(self, stmt_name, gvl_PQdescribePrepared);
}


  








  

    #sync_encrypt_password(*args)  
  

  [ GitHub ]


  

  


# File 'ext/pg_connection.c', line 423



static VALUE
pgconn_sync_encrypt_password(int argc, VALUE *argv, VALUE self)
{
	char *encrypted = NULL;
	VALUE rval = Qnil;
	VALUE password, username, algorithm;
	PGconn *conn = pg_get_pgconn(self);

	rb_scan_args( argc, argv, "21", &password, &username, &algorithm );

	Check_Type(password, T_STRING);
	Check_Type(username, T_STRING);

	encrypted = gvl_PQencryptPasswordConn(conn, StringValueCStr(password), StringValueCStr(username), RTEST(algorithm) ? StringValueCStr(algorithm) : NULL);
	if ( encrypted ) {
		rval = rb_str_new2( encrypted );
		PQfreemem( encrypted );
	} else {
		pg_raise_conn_error( rb_ePGerror, self, "%s", PQerrorMessage(conn));
	}

	return rval;
}


  








  

    

      #sync_exec(sql)  ⇒ PG::Result 
      #sync_exec(sql) {|pg_result| ... } 
    

  



  

    

This function has the same behavior as #async_exec, but is implemented using the synchronous command processing API of libpq. It’s not recommended to use explicit sync or async variants but #exec instead, unless you have a good reason to do so.



Both #sync_exec and #async_exec release the GVL while waiting for server response, so that concurrent threads will get executed. However #async_exec has two advantages:


  1. 

    #async_exec can be aborted by signals (like Ctrl-C), while #exec blocks signal processing until the query is answered.
    

  2. 

    Ruby VM gets notified about IO blocked operations and can pass them through Fiber.scheduler. So only async_* methods are compatible to event based schedulers like the async gem.
    



  





  


  [ GitHub ]


  

  


# File 'ext/pg_connection.c', line 1088



static VALUE
pgconn_sync_exec(int argc, VALUE *argv, VALUE self)
{
	t_pg_connection *this = pg_get_connection_safe( self );
	PGresult *result = NULL;
	VALUE rb_pgresult;

	/* If called with no or nil parameters, use PQexec for compatibility */
	if ( argc == 1 || (argc >= 2 && argc <= 4 && NIL_P(argv[1]) )) {
		VALUE query_str = argv[0];

		result = gvl_PQexec(this->pgconn, pg_cstr_enc(query_str, this->enc_idx));
		rb_pgresult = pg_new_result(result, self);
		pg_result_check(rb_pgresult);
		if (rb_block_given_p()) {
			return rb_ensure(rb_yield, rb_pgresult, pg_result_clear, rb_pgresult);
		}
		return rb_pgresult;
	}
	pg_deprecated(0, ("forwarding exec to exec_params is deprecated"));

	/* Otherwise, just call #exec_params instead for backward-compatibility */
	return pgconn_sync_exec_params( argc, argv, self );

}


  








  

    

      #sync_exec_params(sql, params[, result_format[, type_map]] )  ⇒ PG::Result 
      #sync_exec_params(sql, params[, result_format[, type_map]] ) {|pg_result| ... } 
    

  



  

    

This function has the same behavior as #async_exec_params, but is implemented using the synchronous command processing API of libpq. See #async_exec for the differences between the two API variants. It’s not recommended to use explicit sync or async variants but #exec_params instead, unless you have a good reason to do so.


  





  


  [ GitHub ]


  

  


# File 'ext/pg_connection.c', line 1389



static VALUE
pgconn_sync_exec_params( int argc, VALUE *argv, VALUE self )
{
	t_pg_connection *this = pg_get_connection_safe( self );
	PGresult *result = NULL;
	VALUE rb_pgresult;
	VALUE command, in_res_fmt;
	int nParams;
	int resultFormat;
	struct query_params_data paramsData = { this->enc_idx };

	/* For compatibility we accept 1 to 4 parameters */
	rb_scan_args(argc, argv, "13", &command, &paramsData.params, &in_res_fmt, &paramsData.typemap);
	paramsData.with_types = 1;

	/*
	 * For backward compatibility no or nil for the second parameter
	 * is passed to #exec
	 */
	if ( NIL_P(paramsData.params) ) {
		pg_deprecated(1, ("forwarding exec_params to exec is deprecated"));
		return pgconn_sync_exec( 1, argv, self );
	}
	pgconn_query_assign_typemap( self, &paramsData );

	resultFormat = NIL_P(in_res_fmt) ? 0 : NUM2INT(in_res_fmt);
	nParams = alloc_query_params( &paramsData );

	result = gvl_PQexecParams(this->pgconn, pg_cstr_enc(command, paramsData.enc_idx), nParams, paramsData.types,
		(const char * const *)paramsData.values, paramsData.lengths, paramsData.formats, resultFormat);

	free_query_params( &paramsData );

	rb_pgresult = pg_new_result(result, self);
	pg_result_check(rb_pgresult);

	if (rb_block_given_p()) {
		return rb_ensure(rb_yield, rb_pgresult, pg_result_clear, rb_pgresult);
	}

	return rb_pgresult;
}


  








  

    

      #sync_exec_prepared(statement_name [, params, result_format[, type_map]] )  ⇒ PG::Result 
      #sync_exec_prepared(statement_name [, params, result_format[, type_map]] ) {|pg_result| ... } 
    

  



  

    

This function has the same behavior as #async_exec_prepared, but is implemented using the synchronous command processing API of libpq. See #async_exec for the differences between the two API variants. It’s not recommended to use explicit sync or async variants but #exec_prepared instead, unless you have a good reason to do so.


  





  


  [ GitHub ]


  

  


# File 'ext/pg_connection.c', line 1489



static VALUE
pgconn_sync_exec_prepared(int argc, VALUE *argv, VALUE self)
{
	t_pg_connection *this = pg_get_connection_safe( self );
	PGresult *result = NULL;
	VALUE rb_pgresult;
	VALUE name, in_res_fmt;
	int nParams;
	int resultFormat;
	struct query_params_data paramsData = { this->enc_idx };

	rb_scan_args(argc, argv, "13", &name, &paramsData.params, &in_res_fmt, &paramsData.typemap);
	paramsData.with_types = 0;

	if(NIL_P(paramsData.params)) {
		paramsData.params = rb_ary_new2(0);
	}
	pgconn_query_assign_typemap( self, &paramsData );

	resultFormat = NIL_P(in_res_fmt) ? 0 : NUM2INT(in_res_fmt);
	nParams = alloc_query_params( &paramsData );

	result = gvl_PQexecPrepared(this->pgconn, pg_cstr_enc(name, paramsData.enc_idx), nParams,
		(const char * const *)paramsData.values, paramsData.lengths, paramsData.formats,
		resultFormat);

	free_query_params( &paramsData );

	rb_pgresult = pg_new_result(result, self);
	pg_result_check(rb_pgresult);
	if (rb_block_given_p()) {
		return rb_ensure(rb_yield, rb_pgresult,
			pg_result_clear, rb_pgresult);
	}
	return rb_pgresult;
}


  








  

    #sync_flush  
  

  [ GitHub ]


  

  


# File 'ext/pg_connection.c', line 2303



static VALUE
pgconn_sync_flush(VALUE self)
{
	PGconn *conn = pg_get_pgconn(self);
	int ret = PQflush(conn);
	if(ret == -1)
		pg_raise_conn_error( rb_ePGerror, self, "%s", PQerrorMessage(conn));

	return (ret) ? Qfalse : Qtrue;
}


  








  

    #sync_get_copy_data(*args)  
  

  [ GitHub ]


  

  


# File 'ext/pg_connection.c', line 2745



static VALUE
pgconn_sync_get_copy_data(int argc, VALUE *argv, VALUE self )
{
	VALUE async_in;
	VALUE result;
	int ret;
	char *buffer;
	VALUE decoder;
	t_pg_coder *p_coder = NULL;
	t_pg_connection *this = pg_get_connection_safe( self );

	rb_scan_args(argc, argv, "02", &async_in, &decoder);

	if( NIL_P(decoder) ){
		if( !NIL_P(this->decoder_for_get_copy_data) ){
			p_coder = RTYPEDDATA_DATA( this->decoder_for_get_copy_data );
		}
	} else {
		/* Check argument type and use argument decoder */
		TypedData_Get_Struct(decoder, t_pg_coder, &pg_coder_type, p_coder);
	}

	ret = gvl_PQgetCopyData(this->pgconn, &buffer, RTEST(async_in));
	if(ret == -2){ /* error */
		pg_raise_conn_error( rb_ePGerror, self, "%s", PQerrorMessage(this->pgconn));
	}
	if(ret == -1) { /* No data left */
		return Qnil;
	}
	if(ret == 0) { /* would block */
		return Qfalse;
	}

	if( p_coder ){
		t_pg_coder_dec_func dec_func = pg_coder_dec_func( p_coder, p_coder->format );
		result =  dec_func( p_coder, buffer, ret, 0, 0, this->enc_idx );
	} else {
		result = rb_str_new(buffer, ret);
	}

	PQfreemem(buffer);
	return result;
}


  








  

    #sync_get_last_result()  ⇒ PG::Result   



  

    

This function has the same behavior as #async_get_last_result, but is implemented using the synchronous command processing API of libpq. See #async_exec for the differences between the two API variants. It’s not recommended to use explicit sync or async variants but #get_last_result instead, unless you have a good reason to do so.


  



  [ GitHub ]


  

  


# File 'ext/pg_connection.c', line 3189



static VALUE
pgconn_sync_get_last_result(VALUE self)
{
	PGconn *conn = pg_get_pgconn(self);
	VALUE rb_pgresult = Qnil;
	PGresult *cur, *prev;


	cur = prev = NULL;
	while ((cur = gvl_PQgetResult(conn)) != NULL) {
		int status;

		if (prev) PQclear(prev);
		prev = cur;

		status = PQresultStatus(cur);
		if (status == PGRES_COPY_OUT || status == PGRES_COPY_IN || status == PGRES_COPY_BOTH)
			break;
	}

	if (prev) {
		rb_pgresult = pg_new_result( prev, self );
		pg_result_check(rb_pgresult);
	}

	return rb_pgresult;
}


  








  

    #sync_get_result  
  

  [ GitHub ]


  

  


# File 'ext/pg_connection.c', line 2225



static VALUE
pgconn_sync_get_result(VALUE self)
{
	PGconn *conn = pg_get_pgconn(self);
	PGresult *result;
	VALUE rb_pgresult;

	result = gvl_PQgetResult(conn);
	if(result == NULL)
		return Qnil;
	rb_pgresult = pg_new_result(result, self);
	if (rb_block_given_p()) {
		return rb_ensure(rb_yield, rb_pgresult,
			pg_result_clear, rb_pgresult);
	}
	return rb_pgresult;
}


  








  

    #sync_isnonblocking  
  

  [ GitHub ]


  

  


# File 'ext/pg_connection.c', line 2297



static VALUE
pgconn_sync_isnonblocking(VALUE self)
{
	return PQisnonblocking(pg_get_pgconn(self)) ? Qtrue : Qfalse;
}


  








  

    #sync_pipeline_sync  ⇒ nil   



  

    

This function has the same behavior as #async_pipeline_sync, but is implemented using the synchronous command processing API of libpq. See #async_exec for the differences between the two API variants. It’s not recommended to use explicit sync or async variants but #pipeline_sync instead, unless you have a good reason to do so.



Available since PostgreSQL-14


  



  [ GitHub ]


  

  


# File 'ext/pg_connection.c', line 3816



static VALUE
pgconn_sync_pipeline_sync(VALUE self)
{
	PGconn *conn = pg_get_pgconn(self);
	int res = gvl_PQpipelineSync(conn);
	if( res != 1 )
		pg_raise_conn_error( rb_ePGerror, self, "%s", PQerrorMessage(conn));

	return Qnil;
}


  








  

    #sync_prepare(stmt_name, sql [, param_types ] )  ⇒ PG::Result   



  

    

This function has the same behavior as #async_prepare, but is implemented using the synchronous command processing API of libpq. See #async_exec for the differences between the two API variants. It’s not recommended to use explicit sync or async variants but #prepare instead, unless you have a good reason to do so.


  



  [ GitHub ]


  

  


# File 'ext/pg_connection.c', line 1440



static VALUE
pgconn_sync_prepare(int argc, VALUE *argv, VALUE self)
{
	t_pg_connection *this = pg_get_connection_safe( self );
	PGresult *result = NULL;
	VALUE rb_pgresult;
	VALUE name, command, in_paramtypes;
	VALUE param;
	int i = 0;
	int nParams = 0;
	Oid *paramTypes = NULL;
	const char *name_cstr;
	const char *command_cstr;
	int enc_idx = this->enc_idx;

	rb_scan_args(argc, argv, "21", &name, &command, &in_paramtypes);
	name_cstr = pg_cstr_enc(name, enc_idx);
	command_cstr = pg_cstr_enc(command, enc_idx);

	if(! NIL_P(in_paramtypes)) {
		Check_Type(in_paramtypes, T_ARRAY);
		nParams = (int)RARRAY_LEN(in_paramtypes);
		paramTypes = ALLOC_N(Oid, nParams);
		for(i = 0; i < nParams; i++) {
			param = rb_ary_entry(in_paramtypes, i);
			if(param == Qnil)
				paramTypes[i] = 0;
			else
				paramTypes[i] = NUM2UINT(param);
		}
	}
	result = gvl_PQprepare(this->pgconn, name_cstr, command_cstr, nParams, paramTypes);

	xfree(paramTypes);

	rb_pgresult = pg_new_result(result, self);
	pg_result_check(rb_pgresult);
	return rb_pgresult;
}


  








  

    #sync_put_copy_data(*args)  
  



  

    

Connection INSTANCE METHODS: COPY


  



  [ GitHub ]


  

  


# File 'ext/pg_connection.c', line 2672



static VALUE
pgconn_sync_put_copy_data(int argc, VALUE *argv, VALUE self)
{
	int ret;
	int len;
	t_pg_connection *this = pg_get_connection_safe( self );
	VALUE value;
	VALUE buffer = Qnil;
	VALUE encoder;
	VALUE intermediate = Qnil;
	t_pg_coder *p_coder = NULL;

	rb_scan_args( argc, argv, "11", &value, &encoder );

	if( NIL_P(encoder) ){
		if( NIL_P(this->encoder_for_put_copy_data) ){
			buffer = value;
		} else {
			p_coder = RTYPEDDATA_DATA( this->encoder_for_put_copy_data );
		}
	} else {
		/* Check argument type and use argument encoder */
		TypedData_Get_Struct(encoder, t_pg_coder, &pg_coder_type, p_coder);
	}

	if( p_coder ){
		t_pg_coder_enc_func enc_func;
		int enc_idx = this->enc_idx;

		enc_func = pg_coder_enc_func( p_coder );
		len = enc_func( p_coder, value, NULL, &intermediate, enc_idx);

		if( len == -1 ){
			/* The intermediate value is a String that can be used directly. */
			buffer = intermediate;
		} else {
			buffer = rb_str_new(NULL, len);
			len = enc_func( p_coder, value, RSTRING_PTR(buffer), &intermediate, enc_idx);
			rb_str_set_len( buffer, len );
		}
	}

	Check_Type(buffer, T_STRING);

	ret = gvl_PQputCopyData(this->pgconn, RSTRING_PTR(buffer), RSTRING_LENINT(buffer));
	if(ret == -1)
		pg_raise_conn_error( rb_ePGerror, self, "%s", PQerrorMessage(this->pgconn));

	RB_GC_GUARD(buffer);

	return (ret) ? Qtrue : Qfalse;
}


  








  

    #sync_put_copy_end(*args)  
  

  [ GitHub ]


  

  


# File 'ext/pg_connection.c', line 2725



static VALUE
pgconn_sync_put_copy_end(int argc, VALUE *argv, VALUE self)
{
	VALUE str;
	int ret;
	const char *error_message = NULL;
	t_pg_connection *this = pg_get_connection_safe( self );

	if (rb_scan_args(argc, argv, "01", &str) == 0)
		error_message = NULL;
	else
		error_message = pg_cstr_enc(str, this->enc_idx);

	ret = gvl_PQputCopyEnd(this->pgconn, error_message);
	if(ret == -1)
		pg_raise_conn_error( rb_ePGerror, self, "%s", PQerrorMessage(this->pgconn));

	return (ret) ? Qtrue : Qfalse;
}


  








  

    #sync_reset  
  

  [ GitHub ]


  

  


# File 'ext/pg_connection.c', line 558



static VALUE
pgconn_sync_reset( VALUE self )
{
	pgconn_close_socket_io( self );
	gvl_PQreset( pg_get_pgconn(self) );
	return self;
}


  








  

    #sync_set_client_encoding(encoding)    



  

    

This function has the same behavior as #async_set_client_encoding, but is implemented using the synchronous command processing API of libpq. See #async_exec for the differences between the two API variants. It’s not recommended to use explicit sync or async variants but #set_client_encoding instead, unless you have a good reason to do so.


  



  [ GitHub ]


  

  


# File 'ext/pg_connection.c', line 3067



static VALUE
pgconn_sync_set_client_encoding(VALUE self, VALUE str)
{
	PGconn *conn = pg_get_pgconn( self );

	rb_check_frozen(self);
	Check_Type(str, T_STRING);

	if ( (gvl_PQsetClientEncoding(conn, StringValueCStr(str))) == -1 )
		pg_raise_conn_error( rb_ePGerror, self, "%s", PQerrorMessage(conn));

	pgconn_set_internal_encoding_index( self );

	return Qnil;
}


  








  

    #sync_setnonblocking(state)  
  

  [ GitHub ]


  

  


# File 'ext/pg_connection.c', line 2277



static VALUE
pgconn_sync_setnonblocking(VALUE self, VALUE state)
{
	int arg;
	PGconn *conn = pg_get_pgconn(self);
	rb_check_frozen(self);
	if(state == Qtrue)
		arg = 1;
	else if (state == Qfalse)
		arg = 0;
	else
		rb_raise(rb_eArgError, "Boolean value expected");

	if(PQsetnonblocking(conn, arg) == -1)
		pg_raise_conn_error( rb_ePGerror, self, "%s", PQerrorMessage(conn));

	return Qnil;
}


  








  

    #trace(stream)  ⇒ nil   



  

    

Enables tracing message passing between backend. The trace message will be written to the stream stream, which must implement a method fileno that returns a writable file descriptor.


  



  [ GitHub ]


  

  


# File 'ext/pg_connection.c', line 2851



static VALUE
pgconn_trace(VALUE self, VALUE stream)
{
	VALUE fileno;
	FILE *new_fp;
	int old_fd, new_fd;
	VALUE new_file;
	t_pg_connection *this = pg_get_connection_safe( self );

	rb_check_frozen(self);
	if(!rb_respond_to(stream,rb_intern("fileno")))
		rb_raise(rb_eArgError, "stream does not respond to method: fileno");

	fileno = rb_funcall(stream, rb_intern("fileno"), 0);
	if(fileno == Qnil)
		rb_raise(rb_eArgError, "can't get file descriptor from stream");

	/* Duplicate the file descriptor and re-open
	 * it. Then, make it into a ruby File object
	 * and assign it to an instance variable.
	 * This prevents a problem when the File
	 * object passed to this function is closed
	 * before the connection object is. */
	old_fd = NUM2INT(fileno);
	new_fd = dup(old_fd);
	new_fp = fdopen(new_fd, "w");

	if(new_fp == NULL)
		rb_raise(rb_eArgError, "stream is not writable");

	new_file = rb_funcall(rb_cIO, rb_intern("new"), 1, INT2NUM(new_fd));
	RB_OBJ_WRITE(self, &this->trace_stream, new_file);

	PQtrace(this->pgconn, new_fp);
	return Qnil;
}


  








  

    #transaction {|conn| ... } ⇒ result of the block   



  

    

Executes a BEGIN at the start of the block, and a COMMIT at the end of the block, or ROLLBACK if any exception occurs.


  



  [ GitHub ]


  

  


# File 'lib/pg/connection.rb', line 308



def transaction
	rollback = false
	exec "BEGIN"
	yield(self)
rescue PG::RollbackTransaction
	rollback = true
	cancel if transaction_status == PG::PQTRANS_ACTIVE
	block
	exec "ROLLBACK"
rescue Exception
	rollback = true
	cancel if transaction_status == PG::PQTRANS_ACTIVE
	block
	exec "ROLLBACK"
	raise
ensure
	exec "COMMIT" unless rollback
end


  








  

    #transaction_status    



  

    

returns one of the following statuses:



PQTRANS_IDLE    = 0 (connection idle)
PQTRANS_ACTIVE  = 1 (command in progress)
PQTRANS_INTRANS = 2 (idle, within transaction block)
PQTRANS_INERROR = 3 (idle, within failed transaction)
PQTRANS_UNKNOWN = 4 (cannot determine status)


  



  [ GitHub ]


  

  


# File 'ext/pg_connection.c', line 810



static VALUE
pgconn_transaction_status(VALUE self)
{
	return INT2NUM(PQtransactionStatus(pg_get_pgconn(self)));
}


  








  

    #tty    



  

    

Obsolete function.


  



  [ GitHub ]


  

  


# File 'ext/pg_connection.c', line 735



static VALUE
pgconn_tty(VALUE self)
{
	return rb_str_new2("");
}


  








  

    

      #unescape_bytea(string)  
      #unescape_bytea(string)  
    

  



  

    

Alias for .unescape_bytea.


  





  








  

    #untrace  ⇒ nil   



  

    

Disables the message tracing.


  



  [ GitHub ]


  

  


# File 'ext/pg_connection.c', line 2894



static VALUE
pgconn_untrace(VALUE self)
{
	t_pg_connection *this = pg_get_connection_safe( self );

	PQuntrace(this->pgconn);
	rb_funcall(this->trace_stream, rb_intern("close"), 0);
	RB_OBJ_WRITE(self, &this->trace_stream, Qnil);
	return Qnil;
}


  








  

    #user    



  

    

Returns the authenticated user name.


  



  [ GitHub ]


  

  


# File 'ext/pg_connection.c', line 646



static VALUE
pgconn_user(VALUE self)
{
	char *user = PQuser(pg_get_pgconn(self));
	if (!user) return Qnil;
	return rb_str_new2(user);
}


  








  

    

      #notifies_wait([ timeout ]) {|event, pid, payload| ... } ⇒ String 
      #wait_for_notify([ timeout ]) {|event, pid, payload| ... } ⇒ String 
    

  



  

    

Alias for #notifies_wait.