Drop temporary index on audit_events table

This index was created as part of the clean up on serialize object in
details field. The job has completed and all tainted data has been
removed.

changelogs/unreleased/220124-drop-temp-index-on-audit-events.yml

+---
+title: Drop index of ruby objects in details on audit_events table
+merge_request: 36547
+author:
+type: other

db/post_migrate/20200710102846_drop_index_ruby_objects_in_details_on_audit_events.rb

+# frozen_string_literal: true
+
+class DropIndexRubyObjectsInDetailsOnAuditEvents < ActiveRecord::Migration[6.0]
+  include Gitlab::Database::MigrationHelpers
+
+  DOWNTIME = false
+  INDEX_NAME = 'index_audit_events_on_ruby_object_in_details'
+
+  disable_ddl_transaction!
+
+  def up
+    remove_concurrent_index_by_name(:audit_events, INDEX_NAME)
+  end
+
+  def down
+    add_concurrent_index(:audit_events, :id, where: "details ~~ '%ruby/object%'", name: INDEX_NAME)
+  end
+end

db/structure.sql

@@ -18610,8 +18610,6 @@ CREATE INDEX index_approvers_on_user_id ON public.approvers USING btree (user_id
 
 CREATE INDEX index_audit_events_on_entity_id_entity_type_id_desc_author_id ON public.audit_events USING btree (entity_id, entity_type, id DESC, author_id);
 
-CREATE INDEX index_audit_events_on_ruby_object_in_details ON public.audit_events USING btree (id) WHERE (details ~~ '%ruby/object%'::text);
-
 CREATE INDEX index_award_emoji_on_awardable_type_and_awardable_id ON public.award_emoji USING btree (awardable_type, awardable_id);
 
 CREATE INDEX index_award_emoji_on_user_id_and_name ON public.award_emoji USING btree (user_id, name);
@@ -23650,5 +23648,6 @@ COPY "schema_migrations" (version) FROM STDIN;
 20200707071941
 20200707094341
 20200707095849
+20200710102846
 \.