Commit 1e97a6df authored by Stan Hu's avatar Stan Hu

Add index to labels for `type` and project_id`

When loading pages that display the number of open issues,
the backend runs a query such as:

```sql
SELECT "labels"."id" FROM "labels" WHERE "labels"."type" IN ('ProjectLabel') AND "labels"."project_id" = 1000
```

This results in an entire scan of the `labels` table. To optimize performance,
add the appropriate index to the table.

Closes #27676
parent 8a333d45
class AddIndexToLabelsForTypeAndProject < ActiveRecord::Migration
include Gitlab::Database::MigrationHelpers
DOWNTIME = false
disable_ddl_transaction!
def change
add_concurrent_index :labels, [:type, :project_id]
end
end
...@@ -11,7 +11,7 @@ ...@@ -11,7 +11,7 @@
# #
# It's strongly recommended that you check this file into your version control system. # It's strongly recommended that you check this file into your version control system.
ActiveRecord::Schema.define(version: 20170130204620) do ActiveRecord::Schema.define(version: 20170204181513) do
# These are extensions that must be enabled in order to support this database # These are extensions that must be enabled in order to support this database
enable_extension "plpgsql" enable_extension "plpgsql"
...@@ -576,6 +576,7 @@ ActiveRecord::Schema.define(version: 20170130204620) do ...@@ -576,6 +576,7 @@ ActiveRecord::Schema.define(version: 20170130204620) do
end end
add_index "labels", ["group_id", "project_id", "title"], name: "index_labels_on_group_id_and_project_id_and_title", unique: true, using: :btree add_index "labels", ["group_id", "project_id", "title"], name: "index_labels_on_group_id_and_project_id_and_title", unique: true, using: :btree
add_index "labels", ["type", "project_id"], name: "index_labels_on_type_and_project_id", using: :btree
create_table "lfs_objects", force: :cascade do |t| create_table "lfs_objects", force: :cascade do |t|
t.string "oid", null: false t.string "oid", null: false
......
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