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|
# frozen_string_literal: true
require "concurrent/map"
module ActiveRecord
module ConnectionAdapters # :nodoc:
module QueryCache
class << self
def included(base) #:nodoc:
dirties_query_cache base, :insert, :update, :delete, :truncate, :truncate_tables,
:rollback_to_savepoint, :rollback_db_transaction
base.set_callback :checkout, :after, :configure_query_cache!
base.set_callback :checkin, :after, :disable_query_cache!
end
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 if @query_cache_enabled
super
end
end_code
end
end
end
module ConnectionPoolConfiguration
def initialize(*)
super
@query_cache_enabled = Concurrent::Map.new { false }
end
def enable_query_cache!
@query_cache_enabled[connection_cache_key(Thread.current)] = true
connection.enable_query_cache! if active_connection?
end
def disable_query_cache!
@query_cache_enabled.delete connection_cache_key(Thread.current)
connection.disable_query_cache! if active_connection?
end
def query_cache_enabled
@query_cache_enabled[connection_cache_key(Thread.current)]
end
end
attr_reader :query_cache, :query_cache_enabled
def initialize(*)
super
@query_cache = Hash.new { |h, sql| h[sql] = {} }
@query_cache_enabled = false
end
# Enable the query cache within the block.
def cache
old, @query_cache_enabled = @query_cache_enabled, true
yield
ensure
@query_cache_enabled = old
clear_query_cache unless @query_cache_enabled
end
def enable_query_cache!
@query_cache_enabled = true
end
def disable_query_cache!
@query_cache_enabled = false
clear_query_cache
end
# Disable the query cache within the block.
def uncached
old, @query_cache_enabled = @query_cache_enabled, false
yield
ensure
@query_cache_enabled = old
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.
def clear_query_cache
@lock.synchronize do
@query_cache.clear
end
end
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)
if preparable.nil?
preparable = prepared_statements ? visitor.preparable : false
end
cache_sql(sql, name, binds) { super(sql, name, binds, preparable: preparable) }
else
super
end
end
private
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
# Database adapters can override this method to
# provide custom cache information.
def cache_notification_info(sql, name, binds)
{
sql: sql,
binds: binds,
type_casted_binds: -> { type_casted_binds(binds) },
name: name,
connection_id: object_id,
cached: true
}
end
# If arel is locked this is a SELECT ... FOR UPDATE or somesuch. Such
# queries should not be cached.
def locked?(arel)
arel = arel.arel if arel.is_a?(Relation)
arel.respond_to?(:locked) && arel.locked
end
def configure_query_cache!
enable_query_cache! if pool.query_cache_enabled
end
end
end
end
|
