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== PostgreSQL Query Analyzer for Rails Provides a PostgreSQL query analysis in your development logs. This is useful for finding indexes that your database may benefit from. There are alternatives available that guess which indexes may help and provide example migrations, but I've found that performing a manual analysis using tools like this typically leads to the best results. == Instructions Install the gem: sudo gem install pg_query_analyzer Require it development (config/enviroments/development.rb): config.gem "pg_query_analyzer" You'll achieve the best results if you have your production database available locally. If you're using Heroku (http://heroku.com) this means setting up your development database to use PostgreSQL and running ("heroku db:pull"). Restart your server ("script/server" or "touch tmp/restart.txt") and tail your development log ("tail -f -n 100 log/development.log") to see the results. Note the "total runtime", "cost", and "actual time" data points to locate long running queries, as you might see in the second example provided below. Once you identify which queries are worth optimizing, you can generate and run migrations to create the appropriate indexes, restart your server, and check your logs to ensure that you're getting the results you expect. Once you're finished, you can comment out or remove the config.gem call. Read more about database indexes here: http://www.therailsway.com/2006/11/21/tracks-part-4 http://blog.evanweaver.com/articles/2007/02/12/table-indexes-in-rails/ http://github.com/eladmeidar/rails_indexes == Example One User Load (2.5ms) SELECT * FROM "users" WHERE ("users"."id" = 2) LIMIT 1 Analyzing User Load Execution Time: 0.002899 Limit (cost=0.00..8.27 rows=1 width=3734) (actual time=0.012..0.012 rows=1 loops=1) Output: id, login, posts_count, followings_count, followers_count, created_at, updated_at,... -> Index Scan using users_pkey on users (cost=0.00..8.27 rows=1 width=3734) (actual time=0.011..0.011 rows=1 loops=1) Output: id, login, posts_count, followings_count, followers_count, created_at, updated_at... Index Cond: (id = 2) Total runtime: 0.052 ms == Example Two FeedItem Load (5.1ms) SELECT * FROM "feed_items" WHERE ("feed_items".user_id = 2) ORDER BY feed_items.post_created_at DESC Analyzing FeedItem Load Execution Time: 0.014169 Sort (cost=248.49..249.21 rows=290 width=32) (actual time=1.870..1.895 rows=290 loops=1) Output: id, user_id, post_id, poster_id, post_created_at, created_at Sort Key: post_created_at Sort Method: quicksort Memory: 47kB -> Seq Scan on feed_items (cost=0.00..236.62 rows=290 width=32) (actual time=0.015..1.735 rows=290 loops=1) Output: id, user_id, post_id, poster_id, post_created_at, created_at Filter: (user_id = 2) Total runtime: 1.948 ms == Credits MODIFIED by John Eberly originally take from http://svn.nfectio.us PostgreSQL and Oracle Adapter from Luca Mearelli http://spazidigitali.com Cooked and gemified by Marcos Piccinini http://github.com/nofxx/query-analyzer PostgreSQL Only Version from Trevor Turk http://github.com/trevorturk/pg_query_analyzer == MIT License Spatial Adapter Copyright (c) 2006 Guilhem Vellut <firstname.lastname@example.org> PostGis Adapter Functions (c) 2008 Marcos Piccinini <nofxx> PostgreSQL Only Version (c) 2010 Trevor Turk <email@example.com> Permission is hereby granted, free of charge, to any person obtaining a copy of this software and associated documentation files (the "Software"), to deal in the Software without restriction, including without limitation the rights to use, copy, modify, merge, publish, distribute, sublicense, and/or sell copies of the Software, and to permit persons to whom the Software is furnished to do so, subject to the following conditions: The above copyright notice and this permission notice shall be included in all copies or substantial portions of the Software. THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE SOFTWARE.