= SQL Logging
{}[https://travis-ci.org/lightyear/sql-logging]
The SQL Logging gem adds useful SQL debugging tools to ActiveRecord. The gem
is a repackaging of the old SQL Logging plug-in for Rails 2.x. It, in turn,
was based on ideas and plug-ins from Adam Doppelt's (standard logging
enhancements) and Nathaniel Talbott (the QueryTrace plug-in).
This gem is for Rails 4+ only. It supports MySQL (including the mysql2 gem),
PostgreSQL and SQLite.
== Usage
Once installed, the out-of-the-box behavior gives you:
- A cleaned-up backtrace after every SQL query, so you know exactly what
piece of code triggered the query.
- A report of the number of rows and rough count of bytes returned after
each query.
- After each request completes, additional summary information telling you
the number of statements executed, as well as a rough total number of
bytes received from the database.
- A top 10 list of SQL executions, sorted by total execution time (based on
the location of the query in code), including the total number of rows
and bytes returned over all executions.
All of this additional information is logged at DEBUG level, so it won't
clutter up your production log files.
== Options
The Top 10 summary provides the most options to customize its behavior.
If you want more or fewer than 10 queries, you can easily change that:
SqlLogging.configuration.top_sql_queries = 5
If you want the sorted by something other than the total execution time,
you can instead sort by the median execution time, number of executions
or rows/bytes returned over all executions of the query:
SqlLogging.configuration.show_top_sql_queries = :median_time
SqlLogging.configuration.show_top_sql_queries = :queries
SqlLogging.configuration.show_top_sql_queries = :rows
SqlLogging.configuration.show_top_sql_queries = :bytes
You can also turn the list off entirely:
SqlLogging.configuration.show_top_sql_queries = false
If you don't want to see query backtraces:
SqlLogging.configuration.show_sql_backtrace = false
=== General Configuration
In addition to the statistics configuration, more general aspects of the gem can
be set through the configuration.
For example, the logger can be set here to store results in alternate location:
SqlLogging.configuration.logger = ActiveSupport::Logger.new(STDOUT)
Additionally, the backtrace cleaner used for generating the call stack can be
configured here:
SqlLogging.configuration.backtrace_cleaner.remove_silencers!
= Acknowledgments
Adam's post describing his logging improvements is at
http://gurge.com/blog/2006/11/09/rails-sql-logging-improvements/.
Nathaniel's QueryTrace is available at
http://terralien.com/projects/querytrace/.
= Contact
Feedback and/or patches to make this gem better are greatly appreciated!
Steve Madsen
Light Year Software, LLC
http://lightyearsoftware.com
steve@lightyearsoftware.com