Occasional ERROR 2003 (HY000) in TiDB: Can't connect to MySQL server on '10.xx.xx.xx' (110)

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Original topic: tidb偶尔出现ERROR 2003 (HY000): Can’t connect to MySQL server on ‘10.xx.xx.xx’ (110)

| username: TiDBer_Nb9UDL1r

[TiDB Usage Environment] Production Environment
[TiDB Version]
[Reproduction Path] What operations were performed when the issue occurred
[Encountered Issue: Issue Phenomenon and Impact]
[Resource Configuration] Go to TiDB Dashboard - Cluster Info - Hosts and take a screenshot of this page
[Attachment: Screenshot/Logs/Monitoring]

| username: TiDBer_Nb9UDL1r | Original post link

The network from the application server to TiDB is normal.

| username: Jasper | Original post link

  1. Check Grafana monitoring to see if TiDB has restarted, path: tidb - server - uptime.
  2. Check the TiDB logs for any errors.
  3. Have you set any connection-related parameters? Is it exceeding the connection limit, such as max-connections?
| username: tidb菜鸟一只 | Original post link

Have you used HAProxy?

| username: TiDBer_vfJBUcxl | Original post link

The main thing is to have log information to be sure.

| username: redgame | Original post link

Is there any security software?

| username: zhanggame1 | Original post link

If you have passed the firewall, check if the firewall has timeout settings and blocking records.