Add protected index into ci_pending_builds table

db/post_migrate/20210610113229_add_index_to_protected_pending_builds.rb

+# frozen_string_literal: true
+
+class AddIndexToProtectedPendingBuilds < ActiveRecord::Migration[6.1]
+  include Gitlab::Database::MigrationHelpers
+
+  INDEX_NAME = 'index_ci_pending_builds_on_protected'
+
+  disable_ddl_transaction!
+
+  def up
+    add_concurrent_index :ci_pending_builds, :protected, name: INDEX_NAME
+  end
+
+  def down
+    remove_concurrent_index_by_name :ci_pending_builds, INDEX_NAME
+  end
+end

db/schema_migrations/20210610113229

+3ad279a7c57e433a8ee349dabd2536c1de9055936b05c26b5469606067eb90d4
\ No newline at end of file

db/structure.sql

@@ -22828,6 +22828,8 @@ CREATE UNIQUE INDEX index_ci_pending_builds_on_build_id ON ci_pending_builds USI
 
 CREATE INDEX index_ci_pending_builds_on_project_id ON ci_pending_builds USING btree (project_id);
 
+CREATE INDEX index_ci_pending_builds_on_protected ON ci_pending_builds USING btree (protected);
+
 CREATE INDEX index_ci_pipeline_artifacts_failed_verification ON ci_pipeline_artifacts USING btree (verification_retry_at NULLS FIRST) WHERE (verification_state = 3);
 
 CREATE INDEX index_ci_pipeline_artifacts_needs_verification ON ci_pipeline_artifacts USING btree (verification_state) WHERE ((verification_state = 0) OR (verification_state = 3));