gitlab-org--gitlab-foss/db/migrate/20160119112418_add_services_default.rb

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# rubocop:disable all
class AddServicesDefault < ActiveRecord::Migration[4.2]
Greatly improve external_issue_tracker performance This greatly improves the performance of Project#external_issue_tracker by moving most of the fields queried in Ruby to the database and letting the database handle all logic. Prior to this change the process of finding an external issue tracker was along the lines of the following: 1. Load all project services into memory. 2. Reduce the list to only services where "issue_tracker?" returns true 3. Reduce the list from step 2 to service where "default?" returns false 4. Find the first service where "activated?" returns true This has to two big problems: 1. Loading all services into memory only to reduce the list down to a single item later on is a waste of memory (and slow timing wise). 2. Calling Array#select followed by Array#reject followed by Array#find allocates extra objects when this really isn't needed. To work around this the following service fields have been moved to the database (instead of being hardcoded): * category * default This in turn means we can get the external issue tracker using the following query: SELECT * FROM services WHERE active IS TRUE AND default IS FALSE AND category = 'issue_tracker' AND project_id = XXX LIMIT 1 This coupled with memoizing the result (just as before this commit) greatly reduces the time it takes for Project#external_issue_tracker to complete. The exact reduction depends on one's environment, but locally the execution time is reduced from roughly 230 ms to only 2 ms (= a reduction of almost 180x). Fixes gitlab-org/gitlab-ce#10771
2016-01-19 07:48:07 -05:00
def up
add_column :services, :default, :boolean, default: false
default = quote_column_name('default')
type = quote_column_name('type')
execute <<-EOF
UPDATE services
SET #{default} = true
WHERE #{type} = 'GitlabIssueTrackerService'
EOF
add_index :services, :default
end
def down
remove_column :services, :default
end
end