Remove unused index

changelogs/unreleased/drop-unused-indexes.yml

+---
+title: Remove unused index for vulnerability severity levels
+merge_request: 29023
+author:
+type: other

db/post_migrate/20200407094005_drop_vulnerability_severity_index.rb

+# frozen_string_literal: true
+
+class DropVulnerabilitySeverityIndex < ActiveRecord::Migration[6.0]
+  include Gitlab::Database::MigrationHelpers
+
+  disable_ddl_transaction!
+
+  DOWNTIME = false
+  INDEX_NAME = 'undefined_vulnerabilities'
+
+  def up
+    remove_concurrent_index_by_name :vulnerability_occurrences, INDEX_NAME
+  end
+
+  def down
+    add_concurrent_index(:vulnerability_occurrences, :id, where: 'severity = 0', name: INDEX_NAME)
+  end
+end

db/post_migrate/20200407094923_drop_vulnerabilities_severity_index.rb

+# frozen_string_literal: true
+
+class DropVulnerabilitiesSeverityIndex < ActiveRecord::Migration[6.0]
+  include Gitlab::Database::MigrationHelpers
+
+  disable_ddl_transaction!
+
+  DOWNTIME = false
+  INDEX_NAME = 'undefined_vulnerability'
+
+  def up
+    remove_concurrent_index_by_name :vulnerabilities, INDEX_NAME
+  end
+
+  def down
+    add_concurrent_index(:vulnerabilities, :id, where: 'severity = 0', name: INDEX_NAME)
+  end
+end

db/structure.sql

@@ -10330,10 +10330,6 @@ CREATE INDEX tmp_build_stage_position_index ON public.ci_builds USING btree (sta
 
 CREATE INDEX tmp_idx_on_user_id_where_bio_is_filled ON public.users USING btree (id) WHERE ((COALESCE(bio, ''::character varying))::text IS DISTINCT FROM ''::text);
 
-CREATE INDEX undefined_vulnerabilities ON public.vulnerability_occurrences USING btree (id) WHERE (severity = 0);
-
-CREATE INDEX undefined_vulnerability ON public.vulnerabilities USING btree (id) WHERE (severity = 0);
-
 CREATE UNIQUE INDEX users_security_dashboard_projects_unique_index ON public.users_security_dashboard_projects USING btree (project_id, user_id);
 
 CREATE UNIQUE INDEX vulnerability_feedback_unique_idx ON public.vulnerability_feedback USING btree (project_id, category, feedback_type, project_fingerprint);
@@ -12938,5 +12934,7 @@ COPY "schema_migrations" (version) FROM STDIN;
 20200403184110
 20200403185127
 20200403185422
+20200407094005
+20200407094923
 \.