Communications link failure

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This topic has been translated from a Chinese forum by GPT and might contain errors.

Original topic: Communications link failure

| username: Holland

[TiDB Usage Environment] Production Environment
[TiDB Version]
v6.5.1
[Reproduction Path] What operations were performed when the issue occurred
Error: Communications link failure, connection pool is druid

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[Encountered Problem: Problem Phenomenon and Impact]
[Resource Configuration] Enter TiDB Dashboard - Cluster Info - Hosts and take a screenshot of this page

[Attachments: Screenshots/Logs/Monitoring]
jdbc:
url: jdbc:mysql://xxxx:4000/xxxx?useAffectedRows=true&useUnicode=true&characterEncoding=UTF-8&useSSL=false&autoReconnect=true&failOverReadOnly=false
tidb configuration:

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| username: caiyfc | Original post link

You can refer to this: Connection Pool and Connection Parameters | PingCAP Documentation Center

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| username: 啦啦啦啦啦 | Original post link

Recently, I encountered this error while performing an upgrade. After adjusting the timeout client and timeout server in the HAProxy configuration to a very large value, it hasn’t appeared again.

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| username: Holland | Original post link

Okay, let me take a look.

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| username: Holland | Original post link

Okay, I’ll set it up and observe.

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| username: caiyfc | Original post link

Got it, I’ll try it next time I encounter it.

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| username: Holland | Original post link

Which one corresponds to proxsql?

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| username: tidb菜鸟一只 | Original post link

Is this error reported continuously, intermittently, or only when executing certain SQL statements? I noticed that the connection time reported in your error is very short, only 2404ms…

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| username: redgame | Original post link

This can happen occasionally.

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| username: Holland | Original post link

It is occasional.

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| username: tidb菜鸟一只 | Original post link

Check the TiDB logs to see if the error is caused by the executed SQL…

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| username: Holland | Original post link

If TiDB does not cause an OOM, will executing SQL errors also result in this phenomenon?

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| username: tidb菜鸟一只 | Original post link

Regular SQL shouldn’t, only OOM-related ones would.

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| username: Holland | Original post link

There are indeed no OOM types, and tidb up was 1 month ago.