module ActiveRecord::ConnectionAdapters::QueryCache
Attributes
Public Class Methods
Source
# File 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
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# File 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
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# File 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.
Source
# File 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.
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# File lib/active_record/connection_adapters/abstract/query_cache.rb, line 71 def disable_query_cache! @query_cache_enabled = false clear_query_cache end
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# File lib/active_record/connection_adapters/abstract/query_cache.rb, line 67 def enable_query_cache! @query_cache_enabled = true end
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# File 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
Source
# File 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.
Private Instance Methods
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# File lib/active_record/connection_adapters/abstract/query_cache.rb, line 145 def cache_notification_info(sql, name, binds) { sql: sql, binds: binds, type_casted_binds: -> { type_casted_binds(binds) }, name: name, connection: self, 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 127 def cache_sql(sql, name, binds) @lock.synchronize do result = if @query_cache[sql].key?(binds) ActiveSupport::Notifications.instrument( "sql.active_record", cache_notification_info(sql, name, binds) ) @query_cache[sql][binds] else @query_cache[sql][binds] = yield end result.dup end end
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# File lib/active_record/connection_adapters/abstract/query_cache.rb, line 156 def configure_query_cache! enable_query_cache! if pool.query_cache_enabled end
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# File lib/active_record/connection_adapters/abstract/query_cache.rb, line 115 def lookup_sql_cache(sql, name, binds) @lock.synchronize do if @query_cache[sql].key?(binds) ActiveSupport::Notifications.instrument( "sql.active_record", cache_notification_info(sql, name, binds) ) @query_cache[sql][binds] end end end