From 34d4360e6efa4f7cce800b2a85d3b68c95140c3d Mon Sep 17 00:00:00 2001
From: =?UTF-8?q?Fredrik=20Adel=C3=B6w?= <freben@gmail.com>
Date: Mon, 11 Nov 2024 17:09:21 +0100
Subject: [PATCH] remove redundant indices
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Signed-off-by: Fredrik Adelöw <freben@gmail.com>
---
 .changeset/twelve-masks-call.md               | 14 +++++
 .../20241111000000_drop_redundant_indices.js  | 57 +++++++++++++++++++
 .../src/tests/migrations.test.ts              | 19 +++++++
 3 files changed, 90 insertions(+)
 create mode 100644 .changeset/twelve-masks-call.md
 create mode 100644 plugins/catalog-backend/migrations/20241111000000_drop_redundant_indices.js

diff --git a/.changeset/twelve-masks-call.md b/.changeset/twelve-masks-call.md
new file mode 100644
index 0000000000..7fc79db655
--- /dev/null
+++ b/.changeset/twelve-masks-call.md
@@ -0,0 +1,14 @@
+---
+'@backstage/plugin-catalog-backend': minor
+---
+
+Drop redundant indices from the database.
+
+The following redundant indices are removed in this version:
+
+- `final_entities_entity_id_idx` - overlaps with `final_entities_pkey`
+- `refresh_state_entity_id_idx` - overlaps with `refresh_state_pkey`
+- `refresh_state_entity_ref_idx` - overlaps with `refresh_state_entity_ref_uniq`
+- `search_key_idx` and `search_value_idx` - these were replaced by the composite index `search_key_value_idx` in #22594
+
+No negative end user impact is expected, but rather that performance should increase due to less index churn.
diff --git a/plugins/catalog-backend/migrations/20241111000000_drop_redundant_indices.js b/plugins/catalog-backend/migrations/20241111000000_drop_redundant_indices.js
new file mode 100644
index 0000000000..142e372cb9
--- /dev/null
+++ b/plugins/catalog-backend/migrations/20241111000000_drop_redundant_indices.js
@@ -0,0 +1,57 @@
+/*
+ * Copyright 2024 The Backstage Authors
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *     http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+
+// @ts-check
+
+/**
+ * @param { import("knex").Knex } knex
+ * @returns { Promise<void> }
+ */
+exports.up = async function up(knex) {
+  await knex.schema.alterTable('final_entities', table => {
+    table.dropIndex([], 'final_entities_entity_id_idx'); // overlaps with final_entities_pkey
+  });
+
+  await knex.schema.alterTable('refresh_state', table => {
+    table.dropIndex([], 'refresh_state_entity_id_idx'); // overlaps with refresh_state_pkey
+    table.dropIndex([], 'refresh_state_entity_ref_idx'); // overlaps with refresh_state_entity_ref_uniq
+  });
+
+  await knex.schema.alterTable('search', table => {
+    table.dropIndex([], 'search_key_idx'); // was replaced by search_key_value_idx in 20240130092632_search_index
+    table.dropIndex([], 'search_value_idx'); // was replaced by search_key_value_idx in 20240130092632_search_index
+  });
+};
+
+/**
+ * @param { import("knex").Knex } knex
+ * @returns { Promise<void> }
+ */
+exports.down = async function down(knex) {
+  await knex.schema.alterTable('final_entities', table => {
+    table.index('entity_id', 'final_entities_entity_id_idx');
+  });
+
+  await knex.schema.alterTable('refresh_state', table => {
+    table.index('entity_id', 'refresh_state_entity_id_idx');
+    table.index('entity_ref', 'refresh_state_entity_ref_idx');
+  });
+
+  await knex.schema.alterTable('search', table => {
+    table.index(['key'], 'search_key_idx');
+    table.index(['value'], 'search_value_idx');
+  });
+};
diff --git a/plugins/catalog-backend/src/tests/migrations.test.ts b/plugins/catalog-backend/src/tests/migrations.test.ts
index 8ee228dd5c..bb840f7a21 100644
--- a/plugins/catalog-backend/src/tests/migrations.test.ts
+++ b/plugins/catalog-backend/src/tests/migrations.test.ts
@@ -502,4 +502,23 @@ describe('migrations', () => {
       await knex.destroy();
     },
   );
+
+  it.each(databases.eachSupportedId())(
+    '20241111000000_drop_redundant_indices.js, %p',
+    async databaseId => {
+      const knex = await databases.init(databaseId);
+
+      await migrateUntilBefore(
+        knex,
+        '20241111000000_drop_redundant_indices.js',
+      );
+
+      await migrateUpOnce(knex);
+
+      await migrateDownOnce(knex);
+
+      expect(true).toBe(true);
+      await knex.destroy();
+    },
+  );
 });