Remove unused index for container scanning reports

Index no longer used

changelogs/unreleased/remove-unused-index-for-cs-reports.yml

+---
+title: Remove temporary index for container scanning findings
+merge_request: 44131
+author:
+type: other

db/post_migrate/20201002094617_remove_container_scanning_report_type_index.rb

+# frozen_string_literal: true
+
+class RemoveContainerScanningReportTypeIndex < ActiveRecord::Migration[6.0]
+  include Gitlab::Database::MigrationHelpers
+
+  DOWNTIME = false
+  INDEX_NAME = 'idx_container_scanning_findings'
+
+  disable_ddl_transaction!
+
+  def up
+    remove_concurrent_index_by_name(:vulnerability_occurrences, INDEX_NAME)
+  end
+
+  def down
+    # report_type: 2 container scanning
+    add_concurrent_index(
+      :vulnerability_occurrences,
+      :id,
+      where: 'report_type = 2',
+      name: INDEX_NAME
+    )
+  end
+end

db/schema_migrations/20201002094617

+823c72852eeb17eaf43c58e936ac25effdacb335f76562c68a4f90d5b1a32021
\ No newline at end of file

db/structure.sql

@@ -19365,8 +19365,6 @@ CREATE INDEX idx_audit_events_on_entity_id_desc_author_id_created_at ON audit_ev
 
 CREATE INDEX idx_ci_pipelines_artifacts_locked ON ci_pipelines USING btree (ci_ref_id, id) WHERE (locked = 1);
 
-CREATE INDEX idx_container_scanning_findings ON vulnerability_occurrences USING btree (id) WHERE (report_type = 2);
-
 CREATE INDEX idx_deployment_clusters_on_cluster_id_and_kubernetes_namespace ON deployment_clusters USING btree (cluster_id, kubernetes_namespace);
 
 CREATE UNIQUE INDEX idx_deployment_merge_requests_unique_index ON deployment_merge_requests USING btree (deployment_id, merge_request_id);