Merge branch '210051-optimize-or-remove-ldap_users-counter' into 'master'

Optimize  or remove ldap_users counter

Closes #210051

See merge request gitlab-org/gitlab!27197

changelogs/unreleased/210051-optimize-or-remove-ldap_users-counter.yml

+---
+title: Optimize members counters query performance in usage data
+merge_request: 27197
+author:
+type: performance

db/migrate/20200313123934_add_index_on_user_id_type_source_type_ldap_and_created_at_to_members.rb

+# frozen_string_literal: true
+
+class AddIndexOnUserIdTypeSourceTypeLdapAndCreatedAtToMembers < ActiveRecord::Migration[6.0]
+  include Gitlab::Database::MigrationHelpers
+
+  DOWNTIME = false
+  INDEX_NAME = 'index_members_on_user_id_created_at'
+
+  disable_ddl_transaction!
+
+  def up
+    add_concurrent_index :members, [:user_id, :created_at], where: "ldap = TRUE AND type = 'GroupMember' AND source_type = 'Namespace'", name: INDEX_NAME
+  end
+
+  def down
+    remove_concurrent_index :members, INDEX_NAME
+  end
+end

db/schema.rb

@@ -10,7 +10,7 @@
 #
 # It's strongly recommended that you check this file into your version control system.
 
-ActiveRecord::Schema.define(version: 2020_03_12_163407) do
+ActiveRecord::Schema.define(version: 2020_03_13_123934) do
 
   # These are extensions that must be enabled in order to support this database
   enable_extension "pg_trgm"
@@ -2442,6 +2442,7 @@ ActiveRecord::Schema.define(version: 2020_03_12_163407) do
     t.index ["invite_token"], name: "index_members_on_invite_token", unique: true
     t.index ["requested_at"], name: "index_members_on_requested_at"
     t.index ["source_id", "source_type"], name: "index_members_on_source_id_and_source_type"
+    t.index ["user_id", "created_at"], name: "index_members_on_user_id_created_at", where: "((ldap = true) AND ((type)::text = 'GroupMember'::text) AND ((source_type)::text = 'Namespace'::text))"
     t.index ["user_id"], name: "index_members_on_user_id"
   end