module ActiveRecord::ConnectionAdapters::QueryCache
Attributes
query_cache[R]
query_cache_enabled[R]
Public Class Methods
dirties_query_cache(base, *method_names)
click to toggle source
# File activerecord/lib/active_record/connection_adapters/abstract/query_cache.rb, line 16 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
new(*)
click to toggle source
Calls superclass method
# File activerecord/lib/active_record/connection_adapters/abstract/query_cache.rb, line 51 def initialize(*) super @query_cache = Hash.new { |h, sql| h[sql] = {} } @query_cache_enabled = false end
Public Instance Methods
cache() { || ... }
click to toggle source
Enable the query cache within the block.
# File activerecord/lib/active_record/connection_adapters/abstract/query_cache.rb, line 58 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()
click to toggle source
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.
# File activerecord/lib/active_record/connection_adapters/abstract/query_cache.rb, line 89 def clear_query_cache @lock.synchronize do @query_cache.clear end end
disable_query_cache!()
click to toggle source
# File activerecord/lib/active_record/connection_adapters/abstract/query_cache.rb, line 70 def disable_query_cache! @query_cache_enabled = false clear_query_cache end
enable_query_cache!()
click to toggle source
# File activerecord/lib/active_record/connection_adapters/abstract/query_cache.rb, line 66 def enable_query_cache! @query_cache_enabled = true end
select_all(arel, name = nil, binds = [], preparable: nil)
click to toggle source
Calls superclass method
# File activerecord/lib/active_record/connection_adapters/abstract/query_cache.rb, line 95 def select_all(arel, name = nil, binds = [], preparable: nil) if @query_cache_enabled && !locked?(arel) arel = arel_from_relation(arel) sql, binds = to_sql_and_binds(arel, binds) cache_sql(sql, name, binds) { super(sql, name, binds, preparable: preparable) } else super end end
uncached() { || ... }
click to toggle source
Disable the query cache within the block.
# File activerecord/lib/active_record/connection_adapters/abstract/query_cache.rb, line 76 def uncached old, @query_cache_enabled = @query_cache_enabled, false yield ensure @query_cache_enabled = old end
Private Instance Methods
cache_sql(sql, name, binds) { || ... }
click to toggle source
# File activerecord/lib/active_record/connection_adapters/abstract/query_cache.rb, line 107 def cache_sql(sql, name, binds) @lock.synchronize do result = if @query_cache[sql].key?(binds) ActiveSupport::Notifications.instrument( "sql.active_record", sql: sql, binds: binds, type_casted_binds: -> { type_casted_binds(binds) }, name: name, connection_id: object_id, cached: true, ) @query_cache[sql][binds] else @query_cache[sql][binds] = yield end result.dup end end
configure_query_cache!()
click to toggle source
# File activerecord/lib/active_record/connection_adapters/abstract/query_cache.rb, line 135 def configure_query_cache! enable_query_cache! if pool.query_cache_enabled end
locked?(arel)
click to toggle source
If arel is locked this is a SELECT … FOR UPDATE or somesuch. Such queries should not be cached.
# File activerecord/lib/active_record/connection_adapters/abstract/query_cache.rb, line 130 def locked?(arel) arel = arel.arel if arel.is_a?(Relation) arel.respond_to?(:locked) && arel.locked end