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Refactor ProjectsFinder#init_collection This changes ProjectsFinder#init_collection so it no longer relies on a UNION. For example, to get starred projects of a user we used to run: SELECT projects.* FROM projects WHERE projects.pending_delete = 'f' AND ( projects.id IN ( SELECT projects.id FROM projects INNER JOIN users_star_projects ON users_star_projects.project_id = projects.id INNER JOIN project_authorizations ON projects.id = project_authorizations.project_id WHERE projects.pending_delete = 'f' AND project_authorizations.user_id = 1 AND users_star_projects.user_id = 1 UNION SELECT projects.id FROM projects INNER JOIN users_star_projects ON users_star_projects.project_id = projects.id WHERE projects.visibility_level IN (20, 10) AND users_star_projects.user_id = 1 ) ) ORDER BY projects.id DESC; With these changes the above query is turned into the following instead: SELECT projects.* FROM projects INNER JOIN users_star_projects ON users_star_projects.project_id = projects.id WHERE projects.pending_delete = 'f' AND ( EXISTS ( SELECT 1 FROM project_authorizations WHERE project_authorizations.user_id = 1 AND (project_id = projects.id) ) OR projects.visibility_level IN (20,10) ) AND users_star_projects.user_id = 1 ORDER BY projects.id DESC; This query in turn produces a better execution plan and takes less time, though the difference is only a few milliseconds (this however depends on the amount of data involved and additional conditions that may be added).
2017-06-13 14:44:55 +00:00
---
title: Refactor ProjectsFinder#init_collection to produce more efficient queries for
retrieving projects
merge_request:
author: