mirror of
https://github.com/rails/rails.git
synced 2022-11-09 12:12:34 -05:00
88 lines
3.2 KiB
Ruby
88 lines
3.2 KiB
Ruby
require 'active_support/core_ext/class/attribute'
|
|
|
|
module ActiveRecord
|
|
module Explain
|
|
def self.extended(base)
|
|
# If a query takes longer than these many seconds we log its query plan
|
|
# automatically. nil disables this feature.
|
|
base.config_attribute :auto_explain_threshold_in_seconds, :global => true
|
|
end
|
|
|
|
# If auto explain is enabled, this method triggers EXPLAIN logging for the
|
|
# queries triggered by the block if it takes more than the threshold as a
|
|
# whole. That is, the threshold is not checked against each individual
|
|
# query, but against the duration of the entire block. This approach is
|
|
# convenient for relations.
|
|
#
|
|
# The available_queries_for_explain thread variable collects the queries
|
|
# to be explained. If the value is nil, it means queries are not being
|
|
# currently collected. A false value indicates collecting is turned
|
|
# off. Otherwise it is an array of queries.
|
|
def logging_query_plan # :nodoc:
|
|
return yield unless logger
|
|
|
|
threshold = auto_explain_threshold_in_seconds
|
|
current = Thread.current
|
|
if threshold && current[:available_queries_for_explain].nil?
|
|
begin
|
|
queries = current[:available_queries_for_explain] = []
|
|
start = Time.now
|
|
result = yield
|
|
logger.warn(exec_explain(queries)) if Time.now - start > threshold
|
|
result
|
|
ensure
|
|
current[:available_queries_for_explain] = nil
|
|
end
|
|
else
|
|
yield
|
|
end
|
|
end
|
|
|
|
# Relation#explain needs to be able to collect the queries regardless of
|
|
# whether auto explain is enabled. This method serves that purpose.
|
|
def collecting_queries_for_explain # :nodoc:
|
|
current = Thread.current
|
|
original, current[:available_queries_for_explain] = current[:available_queries_for_explain], []
|
|
return yield, current[:available_queries_for_explain]
|
|
ensure
|
|
# Note that the return value above does not depend on this assigment.
|
|
current[:available_queries_for_explain] = original
|
|
end
|
|
|
|
# Makes the adapter execute EXPLAIN for the tuples of queries and bindings.
|
|
# Returns a formatted string ready to be logged.
|
|
def exec_explain(queries) # :nodoc:
|
|
str = queries && queries.map do |sql, bind|
|
|
[].tap do |msg|
|
|
msg << "EXPLAIN for: #{sql}"
|
|
unless bind.empty?
|
|
bind_msg = bind.map {|col, val| [col.name, val]}.inspect
|
|
msg.last << " #{bind_msg}"
|
|
end
|
|
msg << connection.explain(sql, bind)
|
|
end.join("\n")
|
|
end.join("\n")
|
|
|
|
# overriding inspect to be more human readable
|
|
def str.inspect
|
|
self
|
|
end
|
|
str
|
|
end
|
|
|
|
# Silences automatic EXPLAIN logging for the duration of the block.
|
|
#
|
|
# This has high priority, no EXPLAINs will be run even if downwards
|
|
# the threshold is set to 0.
|
|
#
|
|
# As the name of the method suggests this only applies to automatic
|
|
# EXPLAINs, manual calls to <tt>ActiveRecord::Relation#explain</tt> run.
|
|
def silence_auto_explain
|
|
current = Thread.current
|
|
original, current[:available_queries_for_explain] = current[:available_queries_for_explain], false
|
|
yield
|
|
ensure
|
|
current[:available_queries_for_explain] = original
|
|
end
|
|
end
|
|
end
|