refactor(@angular/build): add composite index on last_accessed in sqlite cache store

Previously, the SQLite cache table had no secondary index on `last_accessed`. Cache eviction routines during `close()` required full table scans for both TTL-based pruning and LRU size-based pruning. Specifically, calculating running sizes using a window function ordered by `last_accessed DESC, key DESC` required SQLite to materialize and sort the entire table in temporary memory on every cache close.

In large persistent caches, these full scans and temporary sorts introduced unnecessary CPU and I/O overhead on shutdown.

A composite index `idx_cache_accessed` on `(last_accessed DESC, key DESC)` is now created on the cache table. This enables SQLite to directly seek entries older than the TTL limit using an indexed binary search and stream rows in descending access order for the window aggregate calculation without requiring an in-memory sort pass.

Author: clydin

packages/angular/build/src/tools/esbuild/sqlite-cache-store.ts

@@ -46,6 +46,9 @@ export class SqliteCacheStore implements PersistentCacheStore<unknown> {
       this.#db.exec(
         'CREATE TABLE IF NOT EXISTS cache (key TEXT PRIMARY KEY, value BLOB, last_accessed INTEGER NOT NULL) WITHOUT ROWID;',
       );
+      this.#db.exec(
+        'CREATE INDEX IF NOT EXISTS idx_cache_accessed ON cache (last_accessed DESC, key DESC);',
+      );
 
       this.#getStmt = this.#db.prepare('SELECT value FROM cache WHERE key = ?');
       this.#hasStmt = this.#db.prepare('SELECT 1 FROM cache WHERE key = ?');

packages/angular/build/src/tools/esbuild/sqlite-cache-store_spec.ts

@@ -187,6 +187,23 @@ describe('SqliteCacheStore', () => {
     checkStore.close();
   });
 
+  it('should create an index on last_accessed and key', async () => {
+    // Trigger db initialization
+    await store.set('test-key', 'test-value');
+    store.close();
+
+    const { DatabaseSync } = await import('node:sqlite');
+    const directDb = new DatabaseSync(cachePath);
+    const indexRows = directDb
+      .prepare(
+        "SELECT name FROM sqlite_master WHERE type = 'index' AND tbl_name = 'cache' AND name = 'idx_cache_accessed'",
+      )
+      .all();
+    directDb.close();
+
+    expect(indexRows.length).toBe(1);
+  });
+
   describe('NG_BUILD_CACHE_STORE env variable option', () => {
     it('should force SQLite when NG_BUILD_CACHE_STORE=sqlite', () => {
       const code = `