Add indices to improve messages_on_delete trigger

ts/test-node/sql/migration_1090_test.ts

@@ -0,0 +1,56 @@
+// Copyright 2024 Signal Messenger, LLC
+// SPDX-License-Identifier: AGPL-3.0-only
+
+import { assert } from 'chai';
+import type { Database } from '@signalapp/better-sqlite3';
+import SQL from '@signalapp/better-sqlite3';
+import { updateToVersion } from './helpers';
+
+describe('SQL/updateToSchemaVersion1090', () => {
+  let db: Database;
+  beforeEach(() => {
+    db = new SQL(':memory:');
+    updateToVersion(db, 1090);
+  });
+
+  afterEach(() => {
+    db.close();
+  });
+
+  describe('Additional messages_on_delete indexes', () => {
+    it('uses index for selecting reactions by messageId', () => {
+      const details = db
+        .prepare(
+          `EXPLAIN QUERY PLAN 
+            SELECT rowid FROM reactions
+            WHERE messageId = '123';
+           `
+        )
+        .all()
+        .map(step => step.detail)
+        .join(', ');
+
+      assert.strictEqual(
+        details,
+        'SEARCH reactions USING COVERING INDEX reactions_messageId (messageId=?)'
+      );
+    });
+
+    it('uses index for selecting storyReads by storyId', () => {
+      const details = db
+        .prepare(
+          `EXPLAIN QUERY PLAN 
+            DELETE FROM storyReads WHERE storyId = '123';
+          `
+        )
+        .all()
+        .map(step => step.detail)
+        .join(', ');
+
+      assert.strictEqual(
+        details,
+        'SEARCH storyReads USING INDEX storyReads_storyId (storyId=?)'
+      );
+    });
+  });
+});