perf: batch gateway submits and isolate callbacks

api/src/prisma/prisma.service.spec.ts

@@ -7,7 +7,25 @@ describe('PrismaService', () => {
     expect(Object.getOwnPropertyDescriptor(prisma, 'operationLog')).toEqual(
       expect.objectContaining({ configurable: true }),
     );
+    expect(prisma.getPoolState()).toEqual({ max: 32, total: 0, idle: 0, waiting: 0 });
 
     await prisma.$disconnect();
   });
+
+  it('reserves a bounded database pool for the isolated Gateway callback process', async () => {
+    const previousRole = process.env.CMPP_PROCESS_ROLE;
+    const previousMax = process.env.API_CALLBACK_DB_POOL_MAX;
+    process.env.CMPP_PROCESS_ROLE = 'callback';
+    process.env.API_CALLBACK_DB_POOL_MAX = '12';
+    try {
+      const prisma = new PrismaService();
+      expect(prisma.getPoolState()).toEqual({ max: 12, total: 0, idle: 0, waiting: 0 });
+      await prisma.$disconnect();
+    } finally {
+      if (previousRole === undefined) delete process.env.CMPP_PROCESS_ROLE;
+      else process.env.CMPP_PROCESS_ROLE = previousRole;
+      if (previousMax === undefined) delete process.env.API_CALLBACK_DB_POOL_MAX;
+      else process.env.API_CALLBACK_DB_POOL_MAX = previousMax;
+    }
+  });
 });

api/src/prisma/prisma.service.ts

@@ -1,30 +1,46 @@
 import { Injectable, OnModuleDestroy } from '@nestjs/common';
 import { PrismaPg } from '@prisma/adapter-pg';
 import { PrismaClient } from '@prisma/client';
+import { Pool } from 'pg';
 import { requestContext } from '../common/request-context';
 
 @Injectable()
 export class PrismaService extends PrismaClient implements OnModuleDestroy {
+  private readonly databasePool: Pool;
+  private readonly databasePoolMax: number;
+
   constructor() {
-    const workerRole = process.env.CMPP_PROCESS_ROLE === 'worker';
-    const databaseUrl = workerRole
-      ? process.env.API_WORKER_DATABASE_URL || process.env.DATABASE_URL
-      : process.env.DATABASE_URL;
-    const configuredPoolMax = Number(workerRole
-      ? process.env.API_WORKER_DB_POOL_MAX ?? 8
-      : process.env.API_DB_POOL_MAX ?? 32);
+    const processRole = process.env.CMPP_PROCESS_ROLE?.trim() || 'api';
+    const workerRole = processRole === 'worker';
+    const outboxRole = processRole === 'outbox';
+    const callbackRole = processRole === 'callback';
+    const databaseUrl = outboxRole
+      ? process.env.API_OUTBOX_DATABASE_URL || process.env.DATABASE_URL
+      : callbackRole
+        ? process.env.API_CALLBACK_DATABASE_URL || process.env.DATABASE_URL
+        : workerRole
+          ? process.env.API_WORKER_DATABASE_URL || process.env.DATABASE_URL
+          : process.env.DATABASE_URL;
+    const configuredPoolMax = Number(outboxRole
+      ? process.env.API_OUTBOX_DB_POOL_MAX ?? 6
+      : callbackRole
+        ? process.env.API_CALLBACK_DB_POOL_MAX ?? 16
+        : workerRole
+          ? process.env.API_WORKER_DB_POOL_MAX ?? 8
+          : process.env.API_DB_POOL_MAX ?? 32);
     const poolMax = Number.isInteger(configuredPoolMax) && configuredPoolMax > 0
       ? configuredPoolMax
-      : workerRole ? 8 : 32;
-    super({
-      adapter: new PrismaPg({
-        connectionString: databaseUrl
-          ?? 'postgresql://cmpp:cmpp_password@localhost:5432/cmpp_platform?schema=public',
-        // API capacity must be reserved independently from the heavier Worker
-        // transactions; explicit bounds also protect PostgreSQL max_connections.
-        max: poolMax,
-      }),
+      : outboxRole ? 6 : callbackRole ? 16 : workerRole ? 8 : 32;
+    const databasePool = new Pool({
+      connectionString: databaseUrl
+        ?? 'postgresql://cmpp:cmpp_password@localhost:5432/cmpp_platform?schema=public',
+      // API capacity must be reserved independently from the heavier Worker
+      // transactions; explicit bounds also protect PostgreSQL max_connections.
+      max: poolMax,
     });
+    super({ adapter: new PrismaPg(databasePool, { disposeExternalPool: true }) });
+    this.databasePool = databasePool;
+    this.databasePoolMax = poolMax;
     const operationLog = this.operationLog;
     Object.defineProperty(this, 'operationLog', {
       value: new Proxy(operationLog, {
@@ -46,6 +62,15 @@ export class PrismaService extends PrismaClient implements OnModuleDestroy {
     });
   }
 
+  getPoolState() {
+    return {
+      max: this.databasePoolMax,
+      total: this.databasePool.totalCount,
+      idle: this.databasePool.idleCount,
+      waiting: this.databasePool.waitingCount,
+    };
+  }
+
   async onModuleDestroy() {
     await this.$disconnect();
   }