Lost connection to MySQL server

[lenovore]

• dble version： 3.21.10.0
• configs：

bootstrap.cnf

-DidleTimeout=600000

• steps：
  Execute a slow sql longer than 600s(the actual execution time is 1200s)

• expect result：

  1. get data

• real result：

  1. after sql execution exceeds 600 seconds, dble re-establishes a backend connection and starts executing the slow sql again. at this time, there are 2 same sqls being executed in the backend. when the first sql execution is completed, an error message is returned: Lost connection to MySQL server
  2. dble.log has a warn message: WARN [complexQueryExecutor87] (com.actiontech.dble.backend.mysql.nio.handler.MultiNodeQueryHandler.connectionClose(MultiNodeQueryHandler.java:214)) - backend connect client closed or timeout killed, conn info:MySQLResponseService ...
  3. but everything is ok when change idleTimeout bigger than 1200000.

[yanhuqing666]

We will try to reproduce the problem

[KlawzZ]

Reproduced successfully
dble version: :dble-3.21.10.0-97a3b6d73a49cb374020f930c59f82746220b424-20211119064810
bootstrap.cnf: -DidleTimeout=6000
steps： execute sql: select sleep(7);
As long as the execution time is longer than the idleTimeout , the above phenomenon will be reproduced

[wenyh1]

From the doc, the introduction to the 'idleTimeout' in bootstrap.cnf is

Is not really an idle connection timeout.
Solution：increase its value.
By the way，We will consider renaming 'idleTimeout'.