如何使用prisma避免java.util.concurrent.ThreadPoolExecutor错误

Question

我目前正在一个大型项目中使用Prisma。当执行一个复杂的查询时，Prisma集群经常会在docker-logs中显示以下错误消息(为了可读性，我修改了这个错误)：

    {"key":"error/unhandled","requestId":"local:ck7ditux500570716cl5f8x3r","clientId":"default$default","payload":{"exception":"java.util.concurrent.RejectedExecutionException: Task slick.basic.BasicBackend$DatabaseDef$$anon$3@552b85a4 rejected from slick.util.AsyncExecutor$$anon$1$$anon$2@1d4391f7[Running, pool size = 9, active threads = 9, queued tasks = 1000, completed tasks = 43440]","query":"query ($where: TaskWhereUniqueInput!)
{\n  task(where: $where) {\n    workflow {\n      tasks {\n        id\n        state\n        parentReq\n        frozen\n        parentTask {\n          id\n          state\n        }\n      }\n    }\n  }\n}\n","variables":
"{\"where\":{\"id\":\"ck6twx873bs550874ne867066\"}}",
"code":"0","stack_trace":"java.util.concurrent.ThreadPoolExecutor$AbortPolicy.rejectedExecution(ThreadPoolExecutor.java:2063)\\n
java.util.concurrent.ThreadPoolExecutor.reject(ThreadPoolExecutor.java:830)
...
"message":"Task slick.basic.BasicBackend$DatabaseDef$$anon$3@552b85a4 rejected from slick.util.AsyncExecutor$$anon$1$$anon$2@1d4391f7[Running, pool size = 9, active threads = 9, queued tasks = 1000, completed tasks = 43440]"}}

这是处理大型查询时经常出现的错误。有没有人想出一种方法来配置Prisma或进行内部批处理操作来避免这种并发错误？

Answer 1

选项1：

当我在一个有大量数据的循环中运行prisma变异时，我遇到了这个问题，这似乎创建了太多的并发数据库操作。

我的解决方案是限制请求：

thingToLoop.map(() => {
  await new Promise(resolve => setTimeout(resolve, 1000));
  // Prisma operation here. Essentially this just makes the operation wait for one second between each operation.
})

选项2

我读过其他帖子，说你也可以限制并发连接的数量。

请参阅：https://v1.prisma.io/docs/1.25/prisma-server/database-connector-POSTGRES-jgfr/#overview

从本质上讲，当创建太多连接时，这会限制连接的数量。请参阅以下prisma配置作为示例：

PRISMA_CONFIG: |
  managementApiSecret: __YOUR_MANAGEMENT_API_SECRET__
  port: 4466
  databases:
    default:
      connector: postgres
      migrations: __ENABLE_DB_MIGRATIONS__
      host: __YOUR_DATABASE_HOST__
      port: __YOUR_DATABASE_PORT__
      user: __YOUR_DATABASE_USER__
      password: __YOUR_DATABASE_PASSWORD__
      connectionLimit: __YOUR_CONNECTION_LIMIT__