From 79696f5b7aaf260176355026e91af05d40d92d0c Mon Sep 17 00:00:00 2001 From: Yorick Peterse Date: Tue, 21 Feb 2017 15:07:02 +0100 Subject: Hash concurrent foreign key names similar to Rails This was initially not implemented simply because I forgot about the size limit of constraint names in PostgreSQL (63 bytes). Using the old technique we can't add foreign keys for certain tables. For example, adding a foreign key on protected_branch_merge_access_levels.protected_branch_id would lead to the following key name: fk_protected_branch_merge_access_levels_protected_branches_protected_branch_id This key is 78 bytes long, thus violating the PostgreSQL size requirements. The hashing strategy is copied from Rails' foreign_key_name() method, which unfortunately is private and subject to change without notice. --- lib/gitlab/database/migration_helpers.rb | 11 ++++++++++- spec/lib/gitlab/database/migration_helpers_spec.rb | 10 ++++++++++ 2 files changed, 20 insertions(+), 1 deletion(-) diff --git a/lib/gitlab/database/migration_helpers.rb b/lib/gitlab/database/migration_helpers.rb index 4800a509b37..fc445ab9483 100644 --- a/lib/gitlab/database/migration_helpers.rb +++ b/lib/gitlab/database/migration_helpers.rb @@ -54,7 +54,7 @@ module Gitlab disable_statement_timeout - key_name = "fk_#{source}_#{target}_#{column}" + key_name = concurrent_foreign_key_name(source, column) # Using NOT VALID allows us to create a key without immediately # validating it. This means we keep the ALTER TABLE lock only for a @@ -74,6 +74,15 @@ module Gitlab execute("ALTER TABLE #{source} VALIDATE CONSTRAINT #{key_name};") end + # Returns the name for a concurrent foreign key. + # + # PostgreSQL constraint names have a limit of 63 bytes. The logic used + # here is based on Rails' foreign_key_name() method, which unfortunately + # is private so we can't rely on it directly. + def concurrent_foreign_key_name(table, column) + "fk_#{Digest::SHA256.hexdigest("#{table}_#{column}_fk").first(10)}" + 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) diff --git a/spec/lib/gitlab/database/migration_helpers_spec.rb b/spec/lib/gitlab/database/migration_helpers_spec.rb index e94ca4fcfd2..e007044868c 100644 --- a/spec/lib/gitlab/database/migration_helpers_spec.rb +++ b/spec/lib/gitlab/database/migration_helpers_spec.rb @@ -101,6 +101,16 @@ describe Gitlab::Database::MigrationHelpers, lib: true do end end + describe '#concurrent_foreign_key_name' do + it 'returns the name for a foreign key' do + name = model.concurrent_foreign_key_name(:this_is_a_very_long_table_name, + :with_a_very_long_column_name) + + expect(name).to be_an_instance_of(String) + expect(name.length).to eq(13) + end + end + describe '#disable_statement_timeout' do context 'using PostgreSQL' do it 'disables statement timeouts' do -- cgit v1.2.1