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module ActiveRecord::ConnectionAdapters::QueryCache

Attributes

query_cache[R]
query_cache_enabled[R]

Public Class Methods

dirties_query_cache(base, *method_names) Show source
# File activerecord/lib/active_record/connection_adapters/abstract/query_cache.rb, line 17
        def dirties_query_cache(base, *method_names)
          method_names.each do |method_name|
            base.class_eval <<-end_code, __FILE__, __LINE__ + 1
              def #{method_name}(*)
                ActiveRecord::Base.clear_query_caches_for_current_thread
                super
              end
            end_code
          end
        end
new(*) Show source
# File activerecord/lib/active_record/connection_adapters/abstract/query_cache.rb, line 52
def initialize(*)
  super
  @query_cache         = Hash.new { |h, sql| h[sql] = {} }
  @query_cache_enabled = false
end
Calls superclass method

Public Instance Methods

cache() { || ... } Show source
# File activerecord/lib/active_record/connection_adapters/abstract/query_cache.rb, line 59
def cache
  old, @query_cache_enabled = @query_cache_enabled, true
  yield
ensure
  @query_cache_enabled = old
  clear_query_cache unless @query_cache_enabled
end

Enable the query cache within the block.

clear_query_cache() Show source
# File activerecord/lib/active_record/connection_adapters/abstract/query_cache.rb, line 90
def clear_query_cache
  @lock.synchronize do
    @query_cache.clear
  end
end

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.

disable_query_cache!() Show source
# File activerecord/lib/active_record/connection_adapters/abstract/query_cache.rb, line 71
def disable_query_cache!
  @query_cache_enabled = false
  clear_query_cache
end
enable_query_cache!() Show source
# File activerecord/lib/active_record/connection_adapters/abstract/query_cache.rb, line 67
def enable_query_cache!
  @query_cache_enabled = true
end
select_all(arel, name = nil, binds = [], preparable: nil, async: false) Show source
# File activerecord/lib/active_record/connection_adapters/abstract/query_cache.rb, line 96
def select_all(arel, name = nil, binds = [], preparable: nil, async: false)
  arel = arel_from_relation(arel)

  # If arel is locked this is a SELECT ... FOR UPDATE or somesuch.
  # Such queries should not be cached.
  if @query_cache_enabled && !(arel.respond_to?(:locked) && arel.locked)
    sql, binds, preparable = to_sql_and_binds(arel, binds, preparable)

    if async
      lookup_sql_cache(sql, name, binds) || super(sql, name, binds, preparable: preparable, async: async)
    else
      cache_sql(sql, name, binds) { super(sql, name, binds, preparable: preparable, async: async) }
    end
  else
    super
  end
end
Calls superclass method
uncached() { || ... } Show source
# File activerecord/lib/active_record/connection_adapters/abstract/query_cache.rb, line 77
def uncached
  old, @query_cache_enabled = @query_cache_enabled, false
  yield
ensure
  @query_cache_enabled = old
end

Disable the query cache within the block.

© 2004–2021 David Heinemeier Hansson
Licensed under the MIT License.