Re: How to resolve "Lock wait timeout exceeded" issue reported by MySQL Cluster

[Mikael Ronström]

Hi,

Jingyu Hu Wrote:
-------------------------------------------------------
> When our system busy with SQL update logic in
> MySQL Cluster, it report below info:
> ----------------------------
> Lock wait timeout exceeded; try restarting
> transaction; nested exception is
> java.sql.SQLException: Lock wait timeout exceeded;
> try restarting transactionCaused by:
> java.sql.SQLException: Lock wait timeout exceeded;
> try restarting transaction
> ----------------------------
>
> Is MySQL cluster NDB engine different to Innodb,
> that difference lead this issue ?
>

MySQL Cluster will report deadlocks differently to how
InnoDB reports them. The most common reason for getting
this kind of error is a deadlock or simply waiting for
another transaction too long.

This happens in InnoDB as well, but there are different
errors reported.

> Or there is no difference between NDB and Innodb
> about SQL Lock logic, that happened comes from our
> system logic ?
>
> Could you help to give me more suggestions to
> resolve this issue ?

Handle the timeout and retry transaction. Also see if
the application is containing deadlocks you can easily
remove or other lock waits that cause issues.

Rgrds Mikael

>
> Best Regards,
> Hu Jingyu