Module: ActiveRecord::ConnectionAdapters::QueryCache

Included in:
AbstractAdapter
Defined in:
lib/active_record/connection_adapters/abstract/query_cache.rb

Instance Attribute Summary collapse

Class Method Summary collapse

Instance Method Summary collapse

Instance Attribute Details

#query_cache ⇒ Object (readonly)

Returns the value of attribute query_cache.



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# File 'lib/active_record/connection_adapters/abstract/query_cache.rb', line 23

def query_cache
  @query_cache
end

#query_cache_enabled ⇒ Object (readonly)

Returns the value of attribute query_cache_enabled.



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# File 'lib/active_record/connection_adapters/abstract/query_cache.rb', line 23

def query_cache_enabled
  @query_cache_enabled
end

Class Method Details

.dirties_query_cache(base, *method_names) ⇒ Object 



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# File 'lib/active_record/connection_adapters/abstract/query_cache.rb', line 11

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

.included(base) ⇒ Object 



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# File 'lib/active_record/connection_adapters/abstract/query_cache.rb', line 7

def included(base)
  dirties_query_cache base, :insert, :update, :delete
end

Instance Method Details

#cache ⇒ Object

Enable the query cache within the block.



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# File 'lib/active_record/connection_adapters/abstract/query_cache.rb', line 26

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

#clear_query_cache ⇒ Object

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.



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# File 'lib/active_record/connection_adapters/abstract/query_cache.rb', line 48

def clear_query_cache
  @query_cache.clear
end

#select_all(*args) ⇒ Object 



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# File 'lib/active_record/connection_adapters/abstract/query_cache.rb', line 52

def select_all(*args)
  if @query_cache_enabled
    cache_sql(args.first) { super }
  else
    super
  end
end

#uncached ⇒ Object

Disable the query cache within the block.



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# File 'lib/active_record/connection_adapters/abstract/query_cache.rb', line 35

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