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Module: ActiveRecord::ConnectionAdapters::QueryCache

Relationships & Source Files
Namespace Children
Modules:
ConnectionPoolConfiguration
Defined in: activerecord/lib/active_record/connection_adapters/abstract/query_cache.rb

Class Method Summary

Instance Attribute Summary

Instance Method Summary

Class Method Details

.dirties_query_cache(base, *method_names)

[ GitHub ] 

  


# File 'activerecord/lib/active_record/connection_adapters/abstract/query_cache.rb', line 16



def dirties_query_cache(base, *method_names)
  method_names.each do |method_name|
    base.class_eval <<-end_code, __FILE__, __LINE__ + 1
      def #{method_name}(*)
        clear_query_cache if @query_cache_enabled
        super
      end
    end_code
  end
end


  







Instance Attribute Details



  

    #query_cache   (readonly)
  

  [ GitHub ]


  

  


# File 'activerecord/lib/active_record/connection_adapters/abstract/query_cache.rb', line 49



attr_reader :query_cache, :query_cache_enabled


  








  

    #query_cache_enabled   (readonly)
  

  [ GitHub ]


  

  


# File 'activerecord/lib/active_record/connection_adapters/abstract/query_cache.rb', line 49



attr_reader :query_cache, :query_cache_enabled


  







Instance Method Details



  

    #cache  
  



  

    

Enable the query cache within the block.


  



  [ GitHub ]


  

  


# File 'activerecord/lib/active_record/connection_adapters/abstract/query_cache.rb', line 58



def cache
  old, @query_cache_enabled = @query_cache_enabled, true
  yield
ensure
  @query_cache_enabled = old
  clear_query_cache unless @query_cache_enabled
end


  








  

    #clear_query_cache  
  



  

    

Clears the query cache.



One reason you may wish to call this method explicitly is between queries that ask the database to randomize results. Otherwise the cache would see the same SQL query and repeatedly return the same result each time, silently undermining the randomness you were expecting.


  



  [ GitHub ]


  

  


# File 'activerecord/lib/active_record/connection_adapters/abstract/query_cache.rb', line 89



def clear_query_cache
  @lock.synchronize do
    @query_cache.clear
  end
end


  








  

    #disable_query_cache!  
  

  [ GitHub ]


  

  


# File 'activerecord/lib/active_record/connection_adapters/abstract/query_cache.rb', line 70



def disable_query_cache!
  @query_cache_enabled = false
  clear_query_cache
end


  








  

    #enable_query_cache!  
  

  [ GitHub ]


  

  


# File 'activerecord/lib/active_record/connection_adapters/abstract/query_cache.rb', line 66



def enable_query_cache!
  @query_cache_enabled = true
end


  








  

    #initialize  
  

  [ GitHub ]


  

  


# File 'activerecord/lib/active_record/connection_adapters/abstract/query_cache.rb', line 51



def initialize(*)
  super
  @query_cache         = Hash.new { |h, sql| h[sql] = {} }
  @query_cache_enabled = false
end


  








  

    #select_all(arel, name = nil, binds = [], preparable: nil)  
  

  [ GitHub ]


  

  


# File 'activerecord/lib/active_record/connection_adapters/abstract/query_cache.rb', line 95



def select_all(arel, name = nil, binds = [], preparable: nil)
  if @query_cache_enabled && !locked?(arel)
    arel = arel_from_relation(arel)
    sql, binds = to_sql_and_binds(arel, binds)

    if preparable.nil?
      preparable = prepared_statements ? visitor.preparable : false
    end

    cache_sql(sql, name, binds) { super(sql, name, binds, preparable: preparable) }
  else
    super
  end
end


  








  

    #uncached  
  



  

    

Disable the query cache within the block.


  



  [ GitHub ]


  

  


# File 'activerecord/lib/active_record/connection_adapters/abstract/query_cache.rb', line 76



def uncached
  old, @query_cache_enabled = @query_cache_enabled, false
  yield
ensure
  @query_cache_enabled = old
end