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https://issues.apache.org/jira/browse/OPENJPA-2693?page=com.atlassian.jira.plugin.system.issuetabpanels:all-tabpanel
]
harold updated OPENJPA-2693:
----------------------------
Description:
i'm using openjpa-all-2.4.0 as my orm and slice solution.here is the scenario:
two clients send http request to our backend api server.cient A's request was
doing some crud operation on db named 'pos' on a seprate mysql host
instance(ip1),client B's request was doing some report query and calculation
on db named 'pos' on an another seprate mysql host(ip2) instance.
and request A was sended later than request B about 1 min,but requst B was
spending lot time about 10 min,during this 10 min,request A was totally
hanging there,until request A finished its job.
so i debuged into the openjpa code ,found something:
1 every brokerimpl is created from a template instance in Class BrokerValue:
public Object newInstance(String clsName, Class type, Configuration conf,
boolean fatal) {
getTemplateBroker(clsName, type, conf, fatal);
try {
return _templateBroker.clone();
} catch (CloneNotSupportedException e) {
throw new InternalException(e);
}
}
the code "_templateBroker.clone()" makes every single DistributedBrokerimpl
instance have a "_lock" prop point to the same instance (ReentrantSliceLock
_lock).
then when do db operation like crud,the code get into
DistributedQueryImpl.execute() method,in this method it invokes
broker.beginOperation(true);
public boolean beginOperation(boolean syncTrans) {
lock();
try {
assertOpen();
if (syncTrans && _operationCount == 0 && _syncManaged
&& (_flags & FLAG_ACTIVE) == 0)
syncWithManagedTransaction();
return _operationCount++ == 1;
} catch (OpenJPAException ke) {
unlock();
throw ke;
} catch (RuntimeException re) {
unlock();
throw new GeneralException(re);
}
}
the lock() method in this beginOperation() is using the _lock prop of
DistributedBrokerImpl instance that cloned from the template instance,
so every other thread will be blocked if there is a thread already call the
lock() method in beginoperation().
this is the root cause in my scenario.
my quesion is : "_templateBroker.clone()" makes every DistributedBrokerImpl
instance have a same "_lock" prop ,is it a bug or is there some intention for
this use?
> slices hangs by another slice db execute
> ----------------------------------------
>
> Key: OPENJPA-2693
> URL: https://issues.apache.org/jira/browse/OPENJPA-2693
> Project: OpenJPA
> Issue Type: Bug
> Components: kernel, slice
> Affects Versions: 2.4.0
> Environment: jdk1.7,win10,tomcat7.0
> Reporter: harold
> Priority: Critical
>
> i'm using openjpa-all-2.4.0 as my orm and slice solution.here is the scenario:
> two clients send http request to our backend api server.cient A's request was
> doing some crud operation on db named 'pos' on a seprate mysql host
> instance(ip1),client B's request was doing some report query and calculation
> on db named 'pos' on an another seprate mysql host(ip2) instance.
> and request A was sended later than request B about 1 min,but requst B was
> spending lot time about 10 min,during this 10 min,request A was totally
> hanging there,until request A finished its job.
> so i debuged into the openjpa code ,found something:
> 1 every brokerimpl is created from a template instance in Class BrokerValue:
> public Object newInstance(String clsName, Class type, Configuration conf,
> boolean fatal) {
> getTemplateBroker(clsName, type, conf, fatal);
> try {
> return _templateBroker.clone();
> } catch (CloneNotSupportedException e) {
> throw new InternalException(e);
> }
> }
> the code "_templateBroker.clone()" makes every single DistributedBrokerimpl
> instance have a "_lock" prop point to the same instance (ReentrantSliceLock
> _lock).
> then when do db operation like crud,the code get into
> DistributedQueryImpl.execute() method,in this method it invokes
> broker.beginOperation(true);
> public boolean beginOperation(boolean syncTrans) {
> lock();
> try {
> assertOpen();
> if (syncTrans && _operationCount == 0 && _syncManaged
> && (_flags & FLAG_ACTIVE) == 0)
> syncWithManagedTransaction();
> return _operationCount++ == 1;
> } catch (OpenJPAException ke) {
> unlock();
> throw ke;
> } catch (RuntimeException re) {
> unlock();
> throw new GeneralException(re);
> }
> }
> the lock() method in this beginOperation() is using the _lock prop of
> DistributedBrokerImpl instance that cloned from the template instance,
> so every other thread will be blocked if there is a thread already call the
> lock() method in beginoperation().
> this is the root cause in my scenario.
> my quesion is : "_templateBroker.clone()" makes every DistributedBrokerImpl
> instance have a same "_lock" prop ,is it a bug or is there some intention for
> this use?
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