Finalize conversion to bigint for ci_sources_pipelines

1. Ensure the migration of `source_job_id` to `bigint` is completed
2. Copy index and FK
3. Swap columns

See https://gitlab.com/gitlab-org/gitlab/-/issues/328436.

Changelog: other

db/post_migrate/20210713042153_finalize_ci_sources_pipelines_bigint_conversion.rb

+# frozen_string_literal: true
+
+class FinalizeCiSourcesPipelinesBigintConversion < ActiveRecord::Migration[6.1]
+  include Gitlab::Database::MigrationHelpers
+
+  disable_ddl_transaction!
+
+  TABLE_NAME = 'ci_sources_pipelines'
+
+  def up
+    ensure_batched_background_migration_is_finished(
+      job_class_name: 'CopyColumnUsingBackgroundMigrationJob',
+      table_name: TABLE_NAME,
+      column_name: 'id',
+      job_arguments: [['source_job_id'], ['source_job_id_convert_to_bigint']]
+    )
+
+    swap
+  end
+
+  def down
+    swap
+  end
+
+  private
+
+  def swap
+    # This is to replace the existing "index_ci_sources_pipelines_on_source_job_id" btree (source_job_id)
+    add_concurrent_index TABLE_NAME, :source_job_id_convert_to_bigint, name: 'index_ci_sources_pipelines_on_source_job_id_convert_to_bigint'
+
+    # Add a foreign key on `source_job_id_convert_to_bigint` before we swap the columns and drop the old FK (fk_be5624bf37)
+    add_concurrent_foreign_key TABLE_NAME, :ci_builds,
+      column: :source_job_id_convert_to_bigint, on_delete: :cascade,
+      name: 'fk_be5624bf37_tmp', reverse_lock_order: true
+
+    with_lock_retries(raise_on_exhaustion: true) do
+      # We'll need  ACCESS EXCLUSIVE lock on the related tables,
+      # lets make sure it can be acquired from the start
+      execute "LOCK TABLE ci_builds, #{TABLE_NAME} IN ACCESS EXCLUSIVE MODE"
+
+      # Swap column names
+      temp_name = 'source_job_id_tmp'
+      execute "ALTER TABLE #{quote_table_name(TABLE_NAME)} RENAME COLUMN #{quote_column_name(:source_job_id)} TO #{quote_column_name(temp_name)}"
+      execute "ALTER TABLE #{quote_table_name(TABLE_NAME)} RENAME COLUMN #{quote_column_name(:source_job_id_convert_to_bigint)} TO #{quote_column_name(:source_job_id)}"
+      execute "ALTER TABLE #{quote_table_name(TABLE_NAME)} RENAME COLUMN #{quote_column_name(temp_name)} TO #{quote_column_name(:source_job_id_convert_to_bigint)}"
+
+      # We need to update the trigger function in order to make PostgreSQL to
+      # regenerate the execution plan for it. This is to avoid type mismatch errors like
+      # "type of parameter 15 (bigint) does not match that when preparing the plan (integer)"
+      function_name = Gitlab::Database::UnidirectionalCopyTrigger.on_table(TABLE_NAME).name(:source_job_id, :source_job_id_convert_to_bigint)
+      execute "ALTER FUNCTION #{quote_table_name(function_name)} RESET ALL"
+
+      # No need to swap defaults, both columns have no default value
+
+      # Rename the index on the `bigint` column to match the new column name
+      # (we already hold an exclusive lock, so no need to use DROP INDEX CONCURRENTLY here)
+      execute 'DROP INDEX index_ci_sources_pipelines_on_source_job_id'
+      rename_index TABLE_NAME, 'index_ci_sources_pipelines_on_source_job_id_convert_to_bigint', 'index_ci_sources_pipelines_on_source_job_id'
+
+      # Drop original FK on the old int4 `source_job_id` (fk_be5624bf37)
+      remove_foreign_key TABLE_NAME, name: 'fk_be5624bf37'
+      # We swapped the columns but the FK is still using the temporary name
+      # So we have to also swap the FK name now that we dropped the other one
+      rename_constraint(TABLE_NAME, 'fk_be5624bf37_tmp', 'fk_be5624bf37')
+    end
+  end
+end

db/schema_migrations/20210713042153

+95aa786acfbd53f1e819e49c6c6ec703d609396f2cc04a5791d1ffc77800dc72
\ No newline at end of file

db/structure.sql

@@ -11269,9 +11269,9 @@ CREATE TABLE ci_sources_pipelines (
     project_id integer,
     pipeline_id integer,
     source_project_id integer,
-    source_job_id integer,
+    source_job_id_convert_to_bigint integer,
     source_pipeline_id integer,
-    source_job_id_convert_to_bigint bigint
+    source_job_id bigint
 );
 
 CREATE SEQUENCE ci_sources_pipelines_id_seq