# Deadlock found when complete task (flowable 6.5, mysql 5.6)

**URL:** <https://forum.flowable.org/t/deadlock-found-when-complete-task-flowable-6-5-mysql-5-6/6248>\
**Category:** Flowable Engine\
**Created:** [June 19, 2020, 8:19am UTC](https://forum.flowable.org/t/deadlock-found-when-complete-task-flowable-6-5-mysql-5-6/6248 "2020-06-19T08:19:11Z")\
**Posts on this page:** 2\
**Page:** 1

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**Author:** ![seasonlai](https://yyz1.discourse-cdn.com/flex035/user_avatar/forum.flowable.org/seasonlai/32/1852_2.png) [@seasonlai](https://forum.flowable.org/u/seasonlai)\
**Post date:** [June 19, 2020, 8:19am UTC](https://forum.flowable.org/t/deadlock-found-when-complete-task-flowable-6-5-mysql-5-6/6248/1 "2020-06-19T08:19:11Z")

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Hi Team，I have a problem.

### Error updating database. Cause: com.mysql.jdbc.exceptions.jdbc4.MySQLTransactionRollbackException: Deadlock found when trying to get lock; try restarting transaction

### The error may involve org.flowable.engine.impl.persistence.entity.ExecutionEntityImpl.updateExecution-Inline

### The error occurred while setting parameters

### SQL: update ACT\_RU\_EXECUTION SET REV\_ = ?, IS\_ACTIVE\_ = ? where ID\_ = ? and REV\_ = ?

### Cause: com.mysql.jdbc.exceptions.jdbc4.MySQLTransactionRollbackException: Deadlock found when trying to get lock; try restarting transaction

```
at org.apache.ibatis.exceptions.ExceptionFactory.wrapException(ExceptionFactory.java:30)
at org.apache.ibatis.session.defaults.DefaultSqlSession.update(DefaultSqlSession.java:200)
at org.flowable.common.engine.impl.db.DbSqlSession.flushUpdates(DbSqlSession.java:570)
at org.flowable.common.engine.impl.db.DbSqlSession.flush(DbSqlSession.java:359)
at org.flowable.common.engine.impl.interceptor.CommandContext.flushSessions(CommandContext.java:192)
at org.flowable.common.engine.impl.interceptor.CommandContext.close(CommandContext.java:61)
at org.flowable.common.engine.impl.interceptor.CommandContextInterceptor.execute(CommandContextInterceptor.java:81)
at org.flowable.common.spring.SpringTransactionInterceptor.lambda$execute$0(SpringTransactionInterceptor.java:56)
at org.springframework.transaction.support.TransactionTemplate.execute(TransactionTemplate.java:140)
at org.flowable.common.spring.SpringTransactionInterceptor.execute(SpringTransactionInterceptor.java:56)
at org.flowable.common.engine.impl.interceptor.LogInterceptor.execute(LogInterceptor.java:30)
at org.flowable.common.engine.impl.cfg.CommandExecutorImpl.execute(CommandExecutorImpl.java:56)
at org.flowable.common.engine.impl.cfg.CommandExecutorImpl.execute(CommandExecutorImpl.java:51)
at org.flowable.engine.impl.TaskServiceImpl.complete(TaskServiceImpl.java:208)
```

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**Author:** ![tjmac](https://avatars.discourse-cdn.com/v4/letter/t/bc8723/32.png) [@tjmac](https://forum.flowable.org/u/tjmac)\
**Post date:** [June 19, 2020, 12:26pm UTC](https://forum.flowable.org/t/deadlock-found-when-complete-task-flowable-6-5-mysql-5-6/6248/2 "2020-06-19T12:26:07Z")

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I just had a similar issue with Flowable and Sql Server. Maybe different issue but this post links to Camunda and that fixed deadlock issues with SQL Server.

> [@MS Sqlserver deadlock thrown on finding process instances](https://forum.flowable.org/t/ms-sqlserver-deadlock-thrown-on-finding-process-instances/508):
>
> Hi, oh no - those deadlocks - oh no - damned you, microsoft ! Anyone with some experiences on deadlocks on SELECT statements with Microsoft SqlServer? Admittedly, we are a bit behind: Still using activiti 5.21 ; and we are not even using the new ASyncExecutor introduced in 5.17 (which is described as being more database friendly) Symptoms: We have occasional deadlock exceptions on the org.activiti.engine.impl.persistence.entity.ExecutionEntityManager.findProcessInstanceAndVariablesByQueryCr…