Merge branch 'disable-statement-timeout' into 'master'

Disable PostgreSQL statement timeout during migrations

Long-running migrations may take more than the timeout allowed by the database. Disable the session's statement timeout to ensure migrations don't get killed prematurely.

See merge request !5263

CHANGELOG

@@ -2,6 +2,7 @@ Please view this file on the master branch, on stable branches it's out of date.
 v 8.10.0 (unreleased)
   - Expose {should,force}_remove_source_branch (Ben Boeckel)
+  - Disable PostgreSQL statement timeout during migrations
   - Fix projects dropdown loading performance with a simplified api cal. !5113 (tiagonbotelho)
   - Fix commit builds API, return all builds for all pipelines for given commit. !4849
   - Replace Haml with Hamlit to make view rendering faster. !3666

lib/gitlab/database/migration_helpers.rb

@@ -20,11 +20,19 @@ module Gitlab
         if Database.postgresql?
           options = options.merge({ algorithm: :concurrently })
+          disable_statement_timeout
         end
         add_index(table_name, column_name, options)
       end
+      # Long-running migrations may take more than the timeout allowed by
+      # the database. Disable the session's statement timeout to ensure
+      # migrations don't get killed prematurely. (PostgreSQL only)
+      def disable_statement_timeout
+        ActiveRecord::Base.connection.execute('SET statement_timeout TO 0') if Database.postgresql?
+      end
+
       # Updates the value of a column in batches.
       #
       # This method updates the table in batches of 5% of the total row count.
@@ -133,6 +141,8 @@ module Gitlab
             'in the body of your migration class'
         end
+        disable_statement_timeout
+
         transaction do
           add_column(table, column, type, default: nil)

spec/lib/gitlab/database/migration_helpers_spec.rb

@@ -13,6 +13,10 @@ describe Gitlab::Database::MigrationHelpers, lib: true do
     context 'outside a transaction' do
       before do
         expect(model).to receive(:transaction_open?).and_return(false)
+
+        unless Gitlab::Database.postgresql?
+          allow_any_instance_of(Gitlab::Database::MigrationHelpers).to receive(:disable_statement_timeout)
+        end
       end
       context 'using PostgreSQL' do