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Module: ActiveRecord::ConnectionAdapters::QueryCache

Class Method Summary

Instance Attribute Summary

Instance Method Summary

Class Method Details

.dirties_query_cache(base, *method_names)

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# File 'activerecord/lib/active_record/connection_adapters/abstract/query_cache.rb', line 9

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)

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# File 'activerecord/lib/active_record/connection_adapters/abstract/query_cache.rb', line 21

attr_reader :query_cache, :query_cache_enabled

#query_cache_enabled (readonly)

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# File 'activerecord/lib/active_record/connection_adapters/abstract/query_cache.rb', line 21

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 30

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 60

def clear_query_cache
  @query_cache.clear
end

#disable_query_cache!

[ GitHub ]

  
# File 'activerecord/lib/active_record/connection_adapters/abstract/query_cache.rb', line 42

def disable_query_cache!
  @query_cache_enabled = false
end

#enable_query_cache!

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# File 'activerecord/lib/active_record/connection_adapters/abstract/query_cache.rb', line 38

def enable_query_cache!
  @query_cache_enabled = true
end

#initialize

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

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

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

[ GitHub ]

  
# File 'activerecord/lib/active_record/connection_adapters/abstract/query_cache.rb', line 64

def select_all(arel, name = nil, binds = [])
  if @query_cache_enabled && !locked?(arel)
    arel, binds = binds_from_relation arel, binds
    sql = to_sql(arel, binds)
    cache_sql(sql, binds) { super(sql, name, binds) }
  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 47

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