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https://issues.apache.org/jira/browse/CLOUDSTACK-9595?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel&focusedCommentId=15690776#comment-15690776
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ASF GitHub Bot commented on CLOUDSTACK-9595:
--------------------------------------------
Github user jburwell commented on the issue:
https://github.com/apache/cloudstack/pull/1762
@serg38 corruption could happen at any point -- it's a ticking time bomb.
From a ACID perspective, this patch fails from a consistency perspective. All
data being updated must be re-queried and validated in order to ensure the
consistency guarantee is not violated. In a high volume system, it's not a
matter of if, but when a sequence of events will occur and corrupt the
database. Bear in mind, these corruptions be in the content of the data and
would not yield a MySQL error. They will be phenomenon such as phantom rows or
inconsistent data updates
As I said previously, the only real solution to deadlocks is to fix the way
the system manages transactions and locks. This patch is merely hiding an
error while creating the potential for far larger problems.
For these reasons, I remain -1 on merging this patch.
> Transactions are not getting retried in case of database deadlock errors
> ------------------------------------------------------------------------
>
> Key: CLOUDSTACK-9595
> URL: https://issues.apache.org/jira/browse/CLOUDSTACK-9595
> Project: CloudStack
> Issue Type: Bug
> Security Level: Public(Anyone can view this level - this is the
> default.)
> Affects Versions: 4.8.0
> Reporter: subhash yedugundla
> Fix For: 4.8.1
>
>
> Customer is seeing occasional error 'Deadlock found when trying to get lock;
> try restarting transaction' messages in their management server logs. It
> happens regularly at least once a day. The following is the error seen
> 2015-12-09 19:23:19,450 ERROR [cloud.api.ApiServer]
> (catalina-exec-3:ctx-f05c58fc ctx-39c17156 ctx-7becdf6e) unhandled exception
> executing api command: [Ljava.lang.String;@230a6e7f
> com.cloud.utils.exception.CloudRuntimeException: DB Exception on:
> com.mysql.jdbc.JDBC4PreparedStatement@74f134e3: DELETE FROM
> instance_group_vm_map WHERE instance_group_vm_map.instance_id = 941374
> at com.cloud.utils.db.GenericDaoBase.expunge(GenericDaoBase.java:1209)
> at sun.reflect.GeneratedMethodAccessor360.invoke(Unknown Source)
> at
> sun.reflect.DelegatingMethodAccessorImpl.invoke(DelegatingMethodAccessorImpl.java:43)
> at java.lang.reflect.Method.invoke(Method.java:606)
> at
> org.springframework.aop.support.AopUtils.invokeJoinpointUsingReflection(AopUtils.java:317)
> at
> org.springframework.aop.framework.ReflectiveMethodInvocation.invokeJoinpoint(ReflectiveMethodInvocation.java:183)
> at
> org.springframework.aop.framework.ReflectiveMethodInvocation.proceed(ReflectiveMethodInvocation.java:150)
> at
> com.cloud.utils.db.TransactionContextInterceptor.invoke(TransactionContextInterceptor.java:34)
> at
> org.springframework.aop.framework.ReflectiveMethodInvocation.proceed(ReflectiveMethodInvocation.java:161)
> at
> org.springframework.aop.interceptor.ExposeInvocationInterceptor.invoke(ExposeInvocationInterceptor.java:91)
> at
> org.springframework.aop.framework.ReflectiveMethodInvocation.proceed(ReflectiveMethodInvocation.java:172)
> at
> org.springframework.aop.framework.JdkDynamicAopProxy.invoke(JdkDynamicAopProxy.java:204)
> at com.sun.proxy.$Proxy237.expunge(Unknown Source)
> at
> com.cloud.vm.UserVmManagerImpl$2.doInTransactionWithoutResult(UserVmManagerImpl.java:2593)
> at
> com.cloud.utils.db.TransactionCallbackNoReturn.doInTransaction(TransactionCallbackNoReturn.java:25)
> at com.cloud.utils.db.Transaction$2.doInTransaction(Transaction.java:57)
> at com.cloud.utils.db.Transaction.execute(Transaction.java:45)
> at com.cloud.utils.db.Transaction.execute(Transaction.java:54)
> at
> com.cloud.vm.UserVmManagerImpl.addInstanceToGroup(UserVmManagerImpl.java:2575)
> at
> com.cloud.vm.UserVmManagerImpl.updateVirtualMachine(UserVmManagerImpl.java:2332)
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