/
explain.rb
74 lines (65 loc) · 2.19 KB
/
explain.rb
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# frozen_string_literal: true
require "active_record/explain_registry"
module ActiveRecord
module Explain
# Executes the block with the collect flag enabled. Queries are collected
# asynchronously by the subscriber and returned.
def collecting_queries_for_explain # :nodoc:
ExplainRegistry.collect = true
yield
ExplainRegistry.queries
ensure
ExplainRegistry.reset
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, options = []) # :nodoc:
str = queries.map do |sql, binds|
msg = +"#{build_explain_clause(options)} #{sql}"
unless binds.empty?
msg << " "
msg << binds.map { |attr| render_bind(attr) }.inspect
end
msg << "\n"
msg << connection_explain(sql, binds, options)
end.join("\n")
# Overriding inspect to be more human readable, especially in the console.
def str.inspect
self
end
str
end
private
def render_bind(attr)
if ActiveModel::Attribute === attr
value = if attr.type.binary? && attr.value
"<#{attr.value_for_database.to_s.bytesize} bytes of binary data>"
else
connection.type_cast(attr.value_for_database)
end
else
value = connection.type_cast(attr)
attr = nil
end
[attr&.name, value]
end
def build_explain_clause(options = [])
if connection.respond_to?(:build_explain_clause, true)
connection.build_explain_clause(options)
else
"EXPLAIN for:"
end
end
def connection_explain(sql, binds, options)
if connection.method(:explain).parameters.size == 2
ActiveRecord.deprecator.warn(<<~MSG.squish)
The current database adapter, #{connection.adapter_name}, does not support explain options.
To remove this warning, the adapter must implement `build_explain_clause(options = [])`.
MSG
connection.explain(sql, binds)
else
connection.explain(sql, binds, options)
end
end
end
end