Class: ActiveRecord::ConnectionAdapters::PostgreSQLAdapter

# File 'activerecord/lib/active_record/connection_adapters/postgresql_adapter.rb', line 105

class_attribute :create_unlogged_tables, default: false

# File 'activerecord/lib/active_record/connection_adapters/postgresql_adapter.rb', line 123

class_attribute :datetime_type, default: :timestamp

# File 'activerecord/lib/active_record/connection_adapters/postgresql_adapter.rb', line 123

class_attribute :datetime_type, default: :timestamp

# File 'activerecord/lib/active_record/connection_adapters/postgresql_adapter.rb', line 132

class_attribute :decode_dates, default: false

# File 'activerecord/lib/active_record/connection_adapters/postgresql_adapter.rb', line 132

class_attribute :decode_dates, default: false

# File 'activerecord/lib/active_record/connection_adapters/postgresql_adapter.rb', line 671

def initialize_type_map(m) # :nodoc:
  m.register_type "int2", Type::Integer.new(limit: 2)
  m.register_type "int4", Type::Integer.new(limit: 4)
  m.register_type "int8", Type::Integer.new(limit: 8)
  m.register_type "oid", OID::Oid.new
  m.register_type "float4", Type::Float.new(limit: 24)
  m.register_type "float8", Type::Float.new
  m.register_type "text", Type::Text.new
  register_class_with_limit m, "varchar", Type::String
  m.alias_type "char", "varchar"
  m.alias_type "name", "varchar"
  m.alias_type "bpchar", "varchar"
  m.register_type "bool", Type::Boolean.new
  register_class_with_limit m, "bit", OID::Bit
  register_class_with_limit m, "varbit", OID::BitVarying
  m.register_type "date", OID::Date.new

  m.register_type "money", OID::Money.new
  m.register_type "bytea", OID::Bytea.new
  m.register_type "point", OID::Point.new
  m.register_type "hstore", OID::Hstore.new
  m.register_type "json", Type::Json.new
  m.register_type "jsonb", OID::Jsonb.new
  m.register_type "cidr", OID::Cidr.new
  m.register_type "inet", OID::Inet.new
  m.register_type "uuid", OID::Uuid.new
  m.register_type "xml", OID::Xml.new
  m.register_type "tsvector", OID::SpecializedString.new(:tsvector)
  m.register_type "macaddr", OID::Macaddr.new
  m.register_type "citext", OID::SpecializedString.new(:citext)
  m.register_type "ltree", OID::SpecializedString.new(:ltree)
  m.register_type "line", OID::SpecializedString.new(:line)
  m.register_type "lseg", OID::SpecializedString.new(:lseg)
  m.register_type "box", OID::SpecializedString.new(:box)
  m.register_type "path", OID::SpecializedString.new(:path)
  m.register_type "polygon", OID::SpecializedString.new(:polygon)
  m.register_type "circle", OID::SpecializedString.new(:circle)

  m.register_type "numeric" do |_, fmod, sql_type|
    precision = extract_precision(sql_type)
    scale = extract_scale(sql_type)

    # The type for the numeric depends on the width of the field,
    # so we'll do something special here.
    #
    # When dealing with decimal columns:
    #
    # places after decimal  = fmod - 4 & 0xffff
    # places before decimal = (fmod - 4) >> 16 & 0xffff
    if fmod && (fmod - 4 & 0xffff).zero?
      # FIXME: Remove this class, and the second argument to
      # lookups on PG
      Type::DecimalWithoutScale.new(precision: precision)
    else
      OID::Decimal.new(precision: precision, scale: scale)
    end
  end

  m.register_type "interval" do |*args, sql_type|
    precision = extract_precision(sql_type)
    OID::Interval.new(precision: precision)
  end
end

# File 'activerecord/lib/active_record/connection_adapters/postgresql_adapter.rb', line 403

def self.native_database_types # :nodoc:
  @native_database_types ||= begin
    types = NATIVE_DATABASE_TYPES.dup
    types[:datetime] = types[datetime_type]
    types
  end
end

# File 'activerecord/lib/active_record/connection_adapters/postgresql_adapter.rb', line 57

def new_client(conn_params)
  PG.connect(**conn_params)
rescue ::PG::Error => error
  if conn_params && conn_params[:dbname] == "postgres"
    raise ActiveRecord::ConnectionNotEstablished, error.message
  elsif conn_params && conn_params[:dbname] && error.message.include?(conn_params[:dbname])
    raise ActiveRecord::NoDatabaseError.db_error(conn_params[:dbname])
  elsif conn_params && conn_params[:user] && error.message.include?(conn_params[:user])
    raise ActiveRecord::DatabaseConnectionError.username_error(conn_params[:user])
  elsif conn_params && conn_params[:host] && error.message.include?(conn_params[:host])
    raise ActiveRecord::DatabaseConnectionError.hostname_error(conn_params[:host])
  else
    raise ActiveRecord::ConnectionNotEstablished, error.message
  end
end

# File 'activerecord/lib/active_record/connection_adapters/postgresql_adapter.rb', line 343

def connected?
  !(@raw_connection.nil? || @raw_connection.finished?)
end

# File 'activerecord/lib/active_record/connection_adapters/postgresql_adapter.rb', line 105

class_attribute :create_unlogged_tables, default: false

# File 'activerecord/lib/active_record/connection_adapters/postgresql_adapter.rb', line 105

class_attribute :create_unlogged_tables, default: false

# File 'activerecord/lib/active_record/connection_adapters/postgresql_adapter.rb', line 123

class_attribute :datetime_type, default: :timestamp

# File 'activerecord/lib/active_record/connection_adapters/postgresql_adapter.rb', line 123

class_attribute :datetime_type, default: :timestamp

# File 'activerecord/lib/active_record/connection_adapters/postgresql_adapter.rb', line 132

class_attribute :decode_dates, default: false

# File 'activerecord/lib/active_record/connection_adapters/postgresql_adapter.rb', line 132

class_attribute :decode_dates, default: false

# File 'activerecord/lib/active_record/connection_adapters/postgresql_adapter.rb', line 903

def in_transaction?
  open_transactions > 0
end

# File 'activerecord/lib/active_record/connection_adapters/postgresql_adapter.rb', line 624

def session_auth=(user)
  clear_cache!
  internal_execute("SET SESSION AUTHORIZATION #{user}", nil, materialize_transactions: true)
end

# File 'activerecord/lib/active_record/connection_adapters/postgresql_adapter.rb', line 419

def supports_advisory_locks?
  true
end

# File 'activerecord/lib/active_record/connection_adapters/postgresql_adapter.rb', line 188

def supports_bulk_alter?
  true
end

# File 'activerecord/lib/active_record/connection_adapters/postgresql_adapter.rb', line 220

def supports_check_constraints?
  true
end

# File 'activerecord/lib/active_record/connection_adapters/postgresql_adapter.rb', line 252

def supports_comments?
  true
end

# File 'activerecord/lib/active_record/connection_adapters/postgresql_adapter.rb', line 450

def supports_common_table_expressions?
  true
end

# File 'activerecord/lib/active_record/connection_adapters/postgresql_adapter.rb', line 244

def supports_datetime_with_precision?
  true
end

# File 'activerecord/lib/active_record/connection_adapters/postgresql_adapter.rb', line 415

def supports_ddl_transactions?
  true
end

# File 'activerecord/lib/active_record/connection_adapters/postgresql_adapter.rb', line 236

def supports_deferrable_constraints?
  true
end

# File 'activerecord/lib/active_record/connection_adapters/postgresql_adapter.rb', line 224

def supports_exclusion_constraints?
  true
end

# File 'activerecord/lib/active_record/connection_adapters/postgresql_adapter.rb', line 423

def supports_explain?
  true
end

# File 'activerecord/lib/active_record/connection_adapters/postgresql_adapter.rb', line 208

def supports_expression_index?
  true
end

# File 'activerecord/lib/active_record/connection_adapters/postgresql_adapter.rb', line 427

def supports_extensions?
  true
end

# File 'activerecord/lib/active_record/connection_adapters/postgresql_adapter.rb', line 216

def supports_foreign_keys?
  true
end

# File 'activerecord/lib/active_record/connection_adapters/postgresql_adapter.rb', line 435

def supports_foreign_tables?
  true
end

# File 'activerecord/lib/active_record/connection_adapters/postgresql_adapter.rb', line 279

def supports_identity_columns? # :nodoc:
  database_version >= 10_00_00 # >= 10.0
end

# File 'activerecord/lib/active_record/connection_adapters/postgresql_adapter.rb', line 204

def supports_index_include?
  database_version >= 11_00_00 # >= 11.0
end

# File 'activerecord/lib/active_record/connection_adapters/postgresql_adapter.rb', line 192

def supports_index_sort_order?
  true
end

# File 'activerecord/lib/active_record/connection_adapters/postgresql_adapter.rb', line 273

alias supports_insert_conflict_target? supports_insert_on_conflict?

# File 'activerecord/lib/active_record/connection_adapters/postgresql_adapter.rb', line 268

def supports_insert_on_conflict?
  database_version >= 9_05_00 # >= 9.5
end

# File 'activerecord/lib/active_record/connection_adapters/postgresql_adapter.rb', line 271

alias supports_insert_on_duplicate_skip? supports_insert_on_conflict?

# File 'activerecord/lib/active_record/connection_adapters/postgresql_adapter.rb', line 272

alias supports_insert_on_duplicate_update? supports_insert_on_conflict?

# File 'activerecord/lib/active_record/connection_adapters/postgresql_adapter.rb', line 264

def supports_insert_returning?
  true
end

# File 'activerecord/lib/active_record/connection_adapters/postgresql_adapter.rb', line 248

def supports_json?
  true
end

# File 'activerecord/lib/active_record/connection_adapters/postgresql_adapter.rb', line 454

def supports_lazy_transactions?
  true
end

# File 'activerecord/lib/active_record/connection_adapters/postgresql_adapter.rb', line 431

def supports_materialized_views?
  true
end

# File 'activerecord/lib/active_record/connection_adapters/postgresql_adapter.rb', line 287

def supports_native_partitioning? # :nodoc:
  database_version >= 10_00_00 # >= 10.0
end

# File 'activerecord/lib/active_record/connection_adapters/postgresql_adapter.rb', line 283

def supports_nulls_not_distinct?
  database_version >= 15_00_00 # >= 15.0
end

# File 'activerecord/lib/active_record/connection_adapters/postgresql_adapter.rb', line 443

def supports_optimizer_hints?
  unless defined?(@has_pg_hint_plan)
    @has_pg_hint_plan = extension_available?("pg_hint_plan")
  end
  @has_pg_hint_plan
end

# File 'activerecord/lib/active_record/connection_adapters/postgresql_adapter.rb', line 200

def supports_partial_index?
  true
end

# File 'activerecord/lib/active_record/connection_adapters/postgresql_adapter.rb', line 196

def supports_partitioned_indexes?
  database_version >= 11_00_00 # >= 11.0
end

# File 'activerecord/lib/active_record/connection_adapters/postgresql_adapter.rb', line 439

def supports_pgcrypto_uuid?
  database_version >= 9_04_00 # >= 9.4
end

# File 'activerecord/lib/active_record/connection_adapters/postgresql_adapter.rb', line 260

def supports_restart_db_transaction?
  database_version >= 12_00_00 # >= 12.0
end

# File 'activerecord/lib/active_record/connection_adapters/postgresql_adapter.rb', line 256

def supports_savepoints?
  true
end

# File 'activerecord/lib/active_record/connection_adapters/postgresql_adapter.rb', line 212

def supports_transaction_isolation?
  true
end

# File 'activerecord/lib/active_record/connection_adapters/postgresql_adapter.rb', line 228

def supports_unique_constraints?
  true
end

# File 'activerecord/lib/active_record/connection_adapters/postgresql_adapter.rb', line 232

def supports_validate_constraints?
  true
end

# File 'activerecord/lib/active_record/connection_adapters/postgresql_adapter.rb', line 240

def supports_views?
  true
end

# File 'activerecord/lib/active_record/connection_adapters/postgresql_adapter.rb', line 275

def supports_virtual_columns?
  database_version >= 12_00_00 # >= 12.0
end

# File 'activerecord/lib/active_record/connection_adapters/postgresql_adapter.rb', line 737

attr_reader :type_map

# File 'activerecord/lib/active_record/connection_adapters/postgresql_adapter.rb', line 629

def use_insert_returning?
  @use_insert_returning
end

# File 'activerecord/lib/active_record/connection_adapters/postgresql_adapter.rb', line 1107

def add_pg_decoders
  @mapped_default_timezone = nil
  @timestamp_decoder = nil

  coders_by_name = {
    "int2" => PG::TextDecoder::Integer,
    "int4" => PG::TextDecoder::Integer,
    "int8" => PG::TextDecoder::Integer,
    "oid" => PG::TextDecoder::Integer,
    "float4" => PG::TextDecoder::Float,
    "float8" => PG::TextDecoder::Float,
    "numeric" => PG::TextDecoder::Numeric,
    "bool" => PG::TextDecoder::Boolean,
    "timestamp" => PG::TextDecoder::TimestampUtc,
    "timestamptz" => PG::TextDecoder::TimestampWithTimeZone,
  }
  coders_by_name["date"] = PG::TextDecoder::Date if decode_dates

  known_coder_types = coders_by_name.keys.map { |n| quote(n) }
  query = <<~SQL % known_coder_types.join(", ")
    SELECT t.oid, t.typname
    FROM pg_type as t
    WHERE t.typname IN (%s)
  SQL
  result = internal_execute(query, "SCHEMA", [], allow_retry: true, materialize_transactions: false)
  coders = result.filter_map { |row| construct_coder(row, coders_by_name[row["typname"]]) }

  map = PG::TypeMapByOid.new
  coders.each { |coder| map.add_coder(coder) }
  @raw_connection.type_map_for_results = map

  @type_map_for_results = PG::TypeMapByOid.new
  @type_map_for_results.default_type_map = map
  @type_map_for_results.add_coder(PG::TextDecoder::Bytea.new(oid: 17, name: "bytea"))
  @type_map_for_results.add_coder(MoneyDecoder.new(oid: 790, name: "money"))

  # extract timestamp decoder for use in update_typemap_for_default_timezone
  @timestamp_decoder = coders.find { |coder| coder.name == "timestamp" }
  update_typemap_for_default_timezone
end

# File 'activerecord/lib/active_record/connection_adapters/postgresql_adapter.rb', line 1080

def add_pg_encoders
  map = PG::TypeMapByClass.new
  map[Integer] = PG::TextEncoder::Integer.new
  map[TrueClass] = PG::TextEncoder::Boolean.new
  map[FalseClass] = PG::TextEncoder::Boolean.new
  @raw_connection.type_map_for_queries = map
end

# File 'activerecord/lib/active_record/connection_adapters/postgresql_adapter.rb', line 1046

def arel_visitor
  Arel::Visitors::PostgreSQL.new(self)
end

# File 'activerecord/lib/active_record/connection_adapters/postgresql_adapter.rb', line 645

def build_insert_sql(insert) # :nodoc:
  sql = +"INSERT #{insert.into} #{insert.values_list}"

  if insert.skip_duplicates?
    sql << " ON CONFLICT #{insert.conflict_target} DO NOTHING"
  elsif insert.update_duplicates?
    sql << " ON CONFLICT #{insert.conflict_target} DO UPDATE SET "
    if insert.raw_update_sql?
      sql << insert.raw_update_sql
    else
      sql << insert.touch_model_timestamps_unless { |column| "#{insert.model.quoted_table_name}.#{column} IS NOT DISTINCT FROM excluded.#{column}" }
      sql << insert.updatable_columns.map { |column| "#{column}=excluded.#{column}" }.join(",")
    end
  end

  sql << " RETURNING #{insert.returning}" if insert.returning
  sql
end

# File 'activerecord/lib/active_record/connection_adapters/postgresql_adapter.rb', line 1050

def build_statement_pool
  StatementPool.new(self, self.class.type_cast_config_to_integer(@config[:statement_limit]))
end

# File 'activerecord/lib/active_record/connection_adapters/postgresql_adapter.rb', line 1054

def can_perform_case_insensitive_comparison_for?(column)
  # NOTE: citext is an exception. It is possible to perform a
  #       case-insensitive comparison using `LOWER()`, but it is
  #       unnecessary, as `citext` is case-insensitive by definition.
  @case_insensitive_cache ||= { "citext" => false }
  @case_insensitive_cache.fetch(column.sql_type) do
    @case_insensitive_cache[column.sql_type] = begin
      sql = <<~SQL
        SELECT exists(
          SELECT * FROM pg_proc
          WHERE proname = 'lower'
            AND proargtypes = ARRAY[#{quote column.sql_type}::regtype]::oidvector
        ) OR exists(
          SELECT * FROM pg_proc
          INNER JOIN pg_cast
            ON ARRAY[casttarget]::oidvector = proargtypes
          WHERE proname = 'lower'
            AND castsource = #{quote column.sql_type}::regtype
        )
      SQL
      result = internal_execute(sql, "SCHEMA", [], allow_retry: true, materialize_transactions: false)
      result.getvalue(0, 0)
    end
  end
end

# File 'activerecord/lib/active_record/connection_adapters/postgresql_adapter.rb', line 664

def check_version # :nodoc:
  if database_version < 9_03_00 # < 9.3
    raise "Your version of PostgreSQL (#{database_version}) is too old. Active Record supports PostgreSQL >= 9.3."
  end
end

# File 'activerecord/lib/active_record/connection_adapters/postgresql_adapter.rb', line 1029

def column_definitions(table_name)
  query(<<~SQL, "SCHEMA")
      SELECT a.attname, format_type(a.atttypid, a.atttypmod),
             pg_get_expr(d.adbin, d.adrelid), a.attnotnull, a.atttypid, a.atttypmod,
             c.collname, col_description(a.attrelid, a.attnum) AS comment,
             #{supports_identity_columns? ? 'attidentity' : quote('')} AS identity,
             #{supports_virtual_columns? ? 'attgenerated' : quote('')} as attgenerated
        FROM pg_attribute a
        LEFT JOIN pg_attrdef d ON a.attrelid = d.adrelid AND a.attnum = d.adnum
        LEFT JOIN pg_type t ON a.atttypid = t.oid
        LEFT JOIN pg_collation c ON a.attcollation = c.oid AND a.attcollation <> t.typcollation
       WHERE a.attrelid = #{quote(quote_table_name(table_name))}::regclass
         AND a.attnum > 0 AND NOT a.attisdropped
       ORDER BY a.attnum
  SQL
end

# File 'activerecord/lib/active_record/connection_adapters/postgresql_adapter.rb', line 951

def configure_connection
  super

  if @config[:encoding]
    @raw_connection.set_client_encoding(@config[:encoding])
  end
  self.client_min_messages = @config[:min_messages] || "warning"
  self.schema_search_path = @config[:schema_search_path] || @config[:schema_order]

  unless ActiveRecord.db_warnings_action.nil?
    @raw_connection.set_notice_receiver do |result|
      message = result.error_field(PG::Result::PG_DIAG_MESSAGE_PRIMARY)
      code = result.error_field(PG::Result::PG_DIAG_SQLSTATE)
      level = result.error_field(PG::Result::PG_DIAG_SEVERITY)
      @notice_receiver_sql_warnings << SQLWarning.new(message, code, level, nil, @pool)
    end
  end

  # Use standard-conforming strings so we don't have to do the E'...' dance.
  set_standard_conforming_strings

  variables = @config.fetch(:variables, {}).stringify_keys

  # Set interval output format to ISO 8601 for ease of parsing by ActiveSupport::Duration.parse
  internal_execute("SET intervalstyle = iso_8601", "SCHEMA")

  # SET statements from :variables config hash
  # https://www.postgresql.org/docs/current/static/sql-set.html
  variables.map do |k, v|
    if v == ":default" || v == :default
      # Sets the value to the global or compile default
      internal_execute("SET SESSION #{k} TO DEFAULT", "SCHEMA")
    elsif !v.nil?
      internal_execute("SET SESSION #{k} TO #{quote(v)}", "SCHEMA")
    end
  end

  add_pg_encoders
  add_pg_decoders

  reload_type_map
end

# File 'activerecord/lib/active_record/connection_adapters/postgresql_adapter.rb', line 933

def connect
  @raw_connection = self.class.new_client(@connection_parameters)
rescue ConnectionNotEstablished => ex
  raise ex.set_pool(@pool)
end

# File 'activerecord/lib/active_record/connection_adapters/postgresql_adapter.rb', line 1148

def construct_coder(row, coder_class)
  return unless coder_class
  coder_class.new(oid: row["oid"].to_i, name: row["typname"])
end

# File 'activerecord/lib/active_record/connection_adapters/postgresql_adapter.rb', line 540

def create_enum(name, values, **options)
  sql_values = values.map { |s| quote(s) }.join(", ")
  scope = quoted_scope(name)
  query = <<~SQL
    DO $$
    BEGIN
        IF NOT EXISTS (
          SELECT 1
          FROM pg_type t
          JOIN pg_namespace n ON t.typnamespace = n.oid
          WHERE t.typname = #{scope[:name]}
            AND n.nspname = #{scope[:schema]}
        ) THEN
            CREATE TYPE #{quote_table_name(name)} AS ENUM (#{sql_values});
        END IF;
    END
    $$;
  SQL
  internal_exec_query(query).tap { reload_type_map }
end

# File 'activerecord/lib/active_record/connection_adapters/postgresql_adapter.rb', line 641

def default_index_type?(index) # :nodoc:
  index.using == :btree || super
end

# File 'activerecord/lib/active_record/connection_adapters/postgresql_adapter.rb', line 485

def disable_extension(name, force: false)
  _schema, name = name.to_s.split(".").values_at(-2, -1)
  internal_exec_query("DROP EXTENSION IF EXISTS \"#{name}\"#{' CASCADE' if force == :cascade}").tap {
    reload_type_map
  }
end

# File 'activerecord/lib/active_record/connection_adapters/postgresql_adapter.rb', line 393

def discard! # :nodoc:
  super
  @raw_connection&.socket_io&.reopen(IO::NULL) rescue nil
  @raw_connection = nil
end

# File 'activerecord/lib/active_record/connection_adapters/postgresql_adapter.rb', line 385

def disconnect!
  @lock.synchronize do
    super
    @raw_connection&.close rescue nil
    @raw_connection = nil
  end
end

# File 'activerecord/lib/active_record/connection_adapters/postgresql_adapter.rb', line 570

def drop_enum(name, values = nil, **options)
  query = <<~SQL
    DROP TYPE#{' IF EXISTS' if options[:if_exists]} #{quote_table_name(name)};
  SQL
  internal_exec_query(query).tap { reload_type_map }
end

# File 'activerecord/lib/active_record/connection_adapters/postgresql_adapter.rb', line 472

def enable_extension(name, **)
  schema, name = name.to_s.split(".").values_at(-2, -1)
  sql = +"CREATE EXTENSION IF NOT EXISTS \"#{name}\""
  sql << " SCHEMA #{schema}" if schema

  internal_exec_query(sql).tap { reload_type_map }
end

# File 'activerecord/lib/active_record/connection_adapters/postgresql_adapter.rb', line 517

def enum_types
  query = <<~SQL
    SELECT
      type.typname AS name,
      type.OID AS oid,
      n.nspname AS schema,
      string_agg(enum.enumlabel, ',' ORDER BY enum.enumsortorder) AS value
    FROM pg_enum AS enum
    JOIN pg_type AS type ON (type.oid = enum.enumtypid)
    JOIN pg_namespace n ON type.typnamespace = n.oid
    WHERE n.nspname = ANY (current_schemas(false))
    GROUP BY type.OID, n.nspname, type.typname;
  SQL

  internal_exec_query(query, "SCHEMA", allow_retry: true, materialize_transactions: false).cast_values.each_with_object({}) do |row, memo|
    name, schema = row[0], row[2]
    schema = nil if schema == current_schema
    full_name = [schema, name].compact.join(".")
    memo[full_name] = row.last
  end.to_a
end

# File 'activerecord/lib/active_record/connection_adapters/postgresql_adapter.rb', line 492

def extension_available?(name)
  query_value("SELECT true FROM pg_available_extensions WHERE name = #{quote(name)}", "SCHEMA")
end

# File 'activerecord/lib/active_record/connection_adapters/postgresql_adapter.rb', line 496

def extension_enabled?(name)
  query_value("SELECT installed_version IS NOT NULL FROM pg_available_extensions WHERE name = #{quote(name)}", "SCHEMA")
end

# File 'activerecord/lib/active_record/connection_adapters/postgresql_adapter.rb', line 500

def extensions
  query = <<~SQL
    SELECT
      pg_extension.extname,
      n.nspname AS schema
    FROM pg_extension
    JOIN pg_namespace n ON pg_extension.extnamespace = n.oid
  SQL

  internal_exec_query(query, "SCHEMA", allow_retry: true, materialize_transactions: false).cast_values.map do |row|
    name, schema = row[0], row[1]
    schema = nil if schema == current_schema
    [schema, name].compact.join(".")
  end
end

# File 'activerecord/lib/active_record/connection_adapters/postgresql_adapter.rb', line 776

def extract_default_function(default_value, default)
  default if has_default_function?(default_value, default)
end

# File 'activerecord/lib/active_record/connection_adapters/postgresql_adapter.rb', line 750

def extract_value_from_default(default)
  case default
    # Quoted types
  when /\A[(B]?'(.*)'.*::"?([\w. ]+)"?(?:\[\])?\z/m
    # The default 'now'::date is CURRENT_DATE
    if $1 == "now" && $2 == "date"
      nil
    else
      $1.gsub("''", "'")
    end
    # Boolean types
  when "true", "false"
    default
    # Numeric types
  when /\A\(?(-?\d+(\.\d*)?)\)?(::bigint)?\z/
    $1
    # Object identifier types
  when /\A-?\d+\z/
    $1
  else
    # Anything else is blank, some user type, or some function
    # and we can't know the value of that, so return nil.
    nil
  end
end

# File 'activerecord/lib/active_record/connection_adapters/postgresql_adapter.rb', line 458

def get_advisory_lock(lock_id) # :nodoc:
  unless lock_id.is_a?(Integer) && lock_id.bit_length <= 63
    raise(ArgumentError, "PostgreSQL requires advisory lock ids to be a signed 64 bit integer")
  end
  query_value("SELECT pg_try_advisory_lock(#{lock_id})")
end

# File 'activerecord/lib/active_record/connection_adapters/postgresql_adapter.rb', line 634

def get_database_version # :nodoc:
  with_raw_connection do |conn|
    conn.server_version
  end
end

# File 'activerecord/lib/active_record/connection_adapters/postgresql_adapter.rb', line 849

def get_oid_type(oid, fmod, column_name, sql_type = "")
  if !type_map.key?(oid)
    load_additional_types([oid])
  end

  type_map.fetch(oid, fmod, sql_type) {
    warn "unknown OID #{oid}: failed to recognize type of '#{column_name}'. It will be treated as String."
    Type.default_value.tap do |cast_type|
      type_map.register_type(oid, cast_type)
    end
  }
end

# File 'activerecord/lib/active_record/connection_adapters/postgresql_adapter.rb', line 780

def has_default_function?(default_value, default)
  !default_value && %r{\w\(.*\)|\(.*\)::\w|CURRENT_DATE|CURRENT_TIMESTAMP}.match?(default)
end

# File 'activerecord/lib/active_record/connection_adapters/postgresql_adapter.rb', line 291

def index_algorithms
  { concurrently: "CONCURRENTLY" }
end

# File 'activerecord/lib/active_record/connection_adapters/postgresql_adapter.rb', line 739

def initialize_type_map(m = type_map)
  self.class.initialize_type_map(m)

  self.class.register_class_with_precision m, "time", Type::Time, timezone: @default_timezone
  self.class.register_class_with_precision m, "timestamp", OID::Timestamp, timezone: @default_timezone
  self.class.register_class_with_precision m, "timestamptz", OID::TimestampWithTimeZone

  load_additional_types
end

# File 'activerecord/lib/active_record/connection_adapters/postgresql_adapter.rb', line 896

def is_cached_plan_failure?(pgerror)
  pgerror.result.result_error_field(PG::PG_DIAG_SQLSTATE) == FEATURE_NOT_SUPPORTED &&
    pgerror.result.result_error_field(PG::PG_DIAG_SOURCE_FUNCTION) == "RevalidateCachedQuery"
rescue
  false
end

# File 'activerecord/lib/active_record/connection_adapters/postgresql_adapter.rb', line 862

def load_additional_types(oids = nil)
  initializer = OID::TypeMapInitializer.new(type_map)
  load_types_queries(initializer, oids) do |query|
    records = internal_execute(query, "SCHEMA", [], allow_retry: true, materialize_transactions: false)
    initializer.run(records)
  end
end

# File 'activerecord/lib/active_record/connection_adapters/postgresql_adapter.rb', line 870

def load_types_queries(initializer, oids)
  query = <<~SQL
    SELECT t.oid, t.typname, t.typelem, t.typdelim, t.typinput, r.rngsubtype, t.typtype, t.typbasetype
    FROM pg_type as t
    LEFT JOIN pg_range as r ON oid = rngtypid
  SQL
  if oids
    yield query + "WHERE t.oid IN (%s)" % oids.join(", ")
  else
    yield query + initializer.query_conditions_for_known_type_names
    yield query + initializer.query_conditions_for_known_type_types
    yield query + initializer.query_conditions_for_array_types
  end
end

# File 'activerecord/lib/active_record/connection_adapters/postgresql_adapter.rb', line 619

def max_identifier_length
  @max_identifier_length ||= query_value("SHOW max_identifier_length", "SCHEMA").to_i
end