node mysql链接报错

Question

问题遇到的现象和发生背景

node写的web网页，部署到centos7上边，跑一段时间就报错了

用代码块功能插入代码，请勿粘贴截图

运行结果及报错内容

events.js:292
      throw er; // Unhandled 'error' event
Error: Packets out of order. Got: 0 Expected: 28
    at Parser._tryReadPacketHeader (/usr/src/sh/node_modules/mysql/lib/protocol/Parser.js:470:15)
    at Parser.write (/usr/src/sh/node_modules/mysql/lib/protocol/Parser.js:33:29)
    at Protocol.write (/usr/src/sh/node_modules/mysql/lib/protocol/Protocol.js:38:16)
    at Socket.<anonymous> (/usr/src/sh/node_modules/mysql/lib/Connection.js:88:28)
    at Socket.<anonymous> (/usr/src/sh/node_modules/mysql/lib/Connection.js:526:10)
    at Socket.emit (events.js:315:20)
    at addChunk (_stream_readable.js:297:12)
    at readableAddChunk (_stream_readable.js:273:9)
    at Socket.Readable.push (_stream_readable.js:214:10)
    at TCP.onStreamRead (internal/stream_base_commons.js:186:23)
Emitted 'error' event on Connection instance at:
    at Connection._handleProtocolError (/usr/src/sh/node_modules/mysql/lib/Connection.js:423:8)
    at Protocol.emit (events.js:315:20)
    at Protocol._delegateError (/usr/src/sh/node_modules/mysql/lib/protocol/Protocol.js:398:10)
    at Protocol.handleParserError (/usr/src/sh/node_modules/mysql/lib/protocol/Protocol.js:380:10)
    at Parser._tryReadPacketHeader (/usr/src/sh/node_modules/mysql/lib/protocol/Parser.js:478:10)
    at Parser.write (/usr/src/sh/node_modules/mysql/lib/protocol/Parser.js:33:29)
    [... lines matching original stack trace ...]
    at Socket.emit (events.js:315:20) {
  code: 'PROTOCOL_PACKETS_OUT_OF_ORDER',
  fatal: true
}

Answer 1

问题 mysql报错：Packets out of order
原因：超出mysql接收的数据包大小。
进入mysql命令行，查询 max_allow_packet： show variables like 'max_allowed_packet';

结果为1048576=1024K=1M。

解决：加大此参数的值，设置为10M，set global max_allowed_packet = 1010241024，重启mysql。

注意：如果配置文件 my.cnf 内默认设置了 max_allow_packet= 1M，那么即使通过命令修改此参数的值为10M，重启mysql也会还原为 1M。所以最好在 my.cnf 内修改max_allow_packet的值。