module ActiveRecord::ConnectionAdapters::QueryCache
Attributes
Public Class Methods
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# File lib/active_record/connection_adapters/abstract/query_cache.rb, line 20 def dirties_query_cache(base, *method_names) method_names.each do |method_name| base.class_eval <<-end_code, __FILE__, __LINE__ + 1 def #{method_name}(...) if pool.dirties_query_cache ActiveRecord::Base.clear_query_caches_for_current_thread end super end end_code end end
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# File lib/active_record/connection_adapters/abstract/query_cache.rb, line 196 def initialize(*) super @query_cache = nil end
Calls superclass method
Public Instance Methods
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# File lib/active_record/connection_adapters/abstract/query_cache.rb, line 206 def cache(&block) pool.enable_query_cache(&block) end
Enable the query cache within the block.
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# File lib/active_record/connection_adapters/abstract/query_cache.rb, line 232 def clear_query_cache pool.clear_query_cache 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.
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# File lib/active_record/connection_adapters/abstract/query_cache.rb, line 222 def disable_query_cache! pool.disable_query_cache! end
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# File lib/active_record/connection_adapters/abstract/query_cache.rb, line 210 def enable_query_cache! pool.enable_query_cache! end
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# File lib/active_record/connection_adapters/abstract/query_cache.rb, line 201 def query_cache_enabled @query_cache&.enabled? end
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# File lib/active_record/connection_adapters/abstract/query_cache.rb, line 218 def uncached(dirties: true, &block) pool.disable_query_cache(dirties: dirties, &block) end
Disable the query cache within the block.
Set dirties: false
to prevent query caches on all connections from being cleared by write operations. (By default, write operations dirty all connections’ query caches in case they are replicas whose cache would now be outdated.)
Private Instance Methods
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# File lib/active_record/connection_adapters/abstract/query_cache.rb, line 308 def cache_notification_info(sql, name, binds) { sql: sql, binds: binds, type_casted_binds: -> { type_casted_binds(binds) }, name: name, connection: self, transaction: current_transaction.user_transaction.presence, cached: true } end
Database adapters can override this method to provide custom cache information.
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# File lib/active_record/connection_adapters/abstract/query_cache.rb, line 300 def cache_notification_info_result(sql, name, binds, result) payload = cache_notification_info(sql, name, binds) payload[:row_count] = result.length payload end
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# File lib/active_record/connection_adapters/abstract/query_cache.rb, line 278 def cache_sql(sql, name, binds) key = binds.empty? ? sql : [sql, binds] result = nil hit = true @lock.synchronize do result = @query_cache.compute_if_absent(key) do hit = false yield end end if hit ActiveSupport::Notifications.instrument( "sql.active_record", cache_notification_info_result(sql, name, binds, result) ) end result.dup end
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# File lib/active_record/connection_adapters/abstract/query_cache.rb, line 260 def lookup_sql_cache(sql, name, binds) key = binds.empty? ? sql : [sql, binds] result = nil @lock.synchronize do result = @query_cache[key] end if result ActiveSupport::Notifications.instrument( "sql.active_record", cache_notification_info_result(sql, name, binds, result) ) end result end
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# File lib/active_record/connection_adapters/abstract/query_cache.rb, line 256 def unset_query_cache! @query_cache = nil end