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

【问题标题】：how to avoid java.util.concurrent.ThreadPoolExecutor error with prisma如何使用 prisma 避免 java.util.concurrent.ThreadPoolExecutor 错误
【发布时间】：2020-06-17 06:26:10
【问题描述】：

我目前正在一个大型项目中使用 Prisma。执行复杂查询时，Prisma 集群经常在 docker-logs 中出错并显示以下消息（为了便于阅读，我正在编辑错误）：

    {"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的常见错误。有没有人想出一种方法来配置 Prisma 或进行内部批处理操作以避免这种并发错误？

【问题讨论】：

标签： docker-compose graphql prisma

【解决方案1】：

选项 1：

我在循环中运行 prisma 突变时遇到了这个问题，其中包含大量似乎创建了太多并发数据库操作的数据。

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

我读过其他帖子说您也可以设置并发连接数的限制。

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

本质上，当创建的连接数过多时，这会限制连接数。以下面的 prisma 配置为例：

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__

【讨论】：