【问题标题】：Knex.js connection error when rerunning the function重新运行函数时出现 Knex.js 连接错误
【发布时间】：2021-06-02 15:29:46
【问题描述】：

我正在使用 Knex 连接到 Azure 数据库，运行一个返回数据库状态的查询（复制/在线）。如果我运行一次，一切都很好。但是，如果我使用 setInterval 重新运行它（我想知道状态何时从 COPYING 更改为 ONLINE），我会在第二次和第三次以及调用函数时遇到连接错误。

这是我的代码

const knex = require('knex')({
  client: 'mssql',
  connection: {
    host: '***',
    user: '***',
    password: '***',
    options: { requestTimeout: 350000, encrypt: true },
  },
  pool: {
    min: 0,
    max: 15,
  },
});
async function copyStatus() {
  try {
    console.log('Running query');
    const status = await knex.raw(
      "SELECT name, state_desc FROM sys.databases WHERE name = 'Tide_QA_Dev_runtime' "
    );
    return status[0].state_desc;
    // console.log(status[0].state_desc);
  } catch (error) {
    console.log(error);
  } finally {
    console.log('Closing connection with database');
    await knex.destroy();
  }
}

function intervalFunc() {
  copyStatus().then(function (result) {
    if (result === 'ONLINE') {
      console.log('Database copy is done.');
    } else if (result === 'Database is still copying') {
      console.log('bezig');
    }
  });
}

setInterval(intervalFunc, 2000);

这是我的输出

Closing connection with database
Database copy is done.
Running query
Error: Unable to acquire a connection
    at Client_MSSQL.acquireConnection (/Users/davidbouckaert/Documents/Qite/TIDE_repo/node_modules/knex/lib/client.js:286:13)
    at Runner.ensureConnection (/Users/davidbouckaert/Documents/Qite/TIDE_repo/node_modules/knex/lib/execution/runner.js:259:46)
    at Runner.run (/Users/davidbouckaert/Documents/Qite/TIDE_repo/node_modules/knex/lib/execution/runner.js:30:30)
    at Raw.Target.then (/Users/davidbouckaert/Documents/Qite/TIDE_repo/node_modules/knex/lib/builder-interface-augmenter.js:24:43)
    at processTicksAndRejections (internal/process/task_queues.js:95:5)
Closing connection with database
Running query
Error: Unable to acquire a connection
    at Client_MSSQL.acquireConnection (/Users/davidbouckaert/Documents/Qite/TIDE_repo/node_modules/knex/lib/client.js:286:13)
    at Runner.ensureConnection (/Users/davidbouckaert/Documents/Qite/TIDE_repo/node_modules/knex/lib/execution/runner.js:259:46)
    at Runner.run (/Users/davidbouckaert/Documents/Qite/TIDE_repo/node_modules/knex/lib/execution/runner.js:30:30)
    at Raw.Target.then (/Users/davidbouckaert/Documents/Qite/TIDE_repo/node_modules/knex/lib/builder-interface-augmenter.js:24:43)
    at processTicksAndRejections (internal/process/task_queues.js:95:5)
Closing connection with database```

It looks like the connection is made (see console log: Running query).
Any idea what's going on?

【问题讨论】：

标签： javascript node.js sql-server azure-sql-database knex.js

【解决方案1】：

你应该使用下面的代码，它对我有用。

const knex = require('knex')({
    client: 'mssql',
    connection: {
        // no tcp:
        server: 'j***2sqlserver.database.windows.net',
        user: 'j***2',
        password: 'J****0',
        database: 'yourdbname',
        port: 1433,
        options: { requestTimeout: 350000, encrypt: true },
    },
    pool: {
        min: 0,
        max: 15,
    },
});

我的测试结果。

【讨论】：

【解决方案2】：

如果您要对数据库进行更多查询，则不应致电 knex.destroy()。

将 knex.destroy() 调用移动到应用程序即将退出之前的某个位置。

【讨论】：