feat: add historic sql aggregate readers

packages/context/src/ingest/adapters/historic-sql/postgres-pgss-reader.test.ts

@@ -0,0 +1,58 @@
+import { describe, expect, it, vi } from 'vitest';
+import { PostgresPgssReader } from './postgres-pgss-reader.js';
+
+describe('PostgresPgssReader aggregate path', () => {
+  it('aggregates pg_stat_statements rows by queryid and query', async () => {
+    const executeQuery = vi.fn(async (sql: string, params?: unknown[]) => {
+      if (sql.includes('pg_stat_statements_info')) {
+        return { headers: ['stats_reset', 'dealloc'], rows: [['2026-05-01T00:00:00.000Z', 1]] };
+      }
+      expect(sql).toContain('GROUP BY queryid, query');
+      expect(sql).toContain('HAVING SUM(calls) >= $1');
+      expect(params).toEqual([5]);
+      return {
+        headers: ['template_id', 'canonical_sql', 'executions', 'distinct_users', 'mean_ms', 'rows_produced', 'top_users'],
+        rows: [
+          [
+            '123',
+            'select status from public.orders',
+            '42',
+            '3',
+            '11.5',
+            '100',
+            JSON.stringify([{ user: 'analyst', executions: 40 }]),
+          ],
+        ],
+      };
+    });
+
+    const reader = new PostgresPgssReader();
+    const rows = [];
+    for await (const row of reader.fetchAggregated(
+      { executeQuery },
+      { start: new Date('2026-02-10T00:00:00.000Z'), end: new Date('2026-05-11T00:00:00.000Z') },
+      { dialect: 'postgres', minExecutions: 5, windowDays: 90, concurrency: 12, filters: {}, redactionPatterns: [], staleArchiveAfterDays: 90 },
+    )) {
+      rows.push(row);
+    }
+
+    expect(rows).toEqual([
+      {
+        templateId: '123',
+        canonicalSql: 'select status from public.orders',
+        dialect: 'postgres',
+        stats: {
+          executions: 42,
+          distinctUsers: 3,
+          firstSeen: '2026-05-01T00:00:00.000Z',
+          lastSeen: '2026-05-11T00:00:00.000Z',
+          p50RuntimeMs: 11.5,
+          p95RuntimeMs: 11.5,
+          errorRate: 0,
+          rowsProduced: 100,
+        },
+        topUsers: [{ user: 'analyst', executions: 40 }],
+      },
+    ]);
+  });
+});