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From "Brian Parkinson" <pa...@avaning.com>
Subject RE: Thread starvation - pool / Throttle issue?
Date Wed, 06 Aug 2008 15:21:51 GMT
Hi Clinton - 
 
Just for clarification
 
1. Using Spring for transactions means that my Dao method
implementartion can be simple (as example below) without
try/catch/finally blocks.
 
2. Using DBCP for connection pooling means that I don't have to
explictly release and connection resources.
 
Please advise - I'm now working on the assumption that my implementation
is good, and that the timeout/deadlock issue is caused by a real
old-fashioned deadlock, as opposed to something I'm not releasing...
 
Upgraded to iBATIS-2.3.3.720 and off to investigate further.
 
All help really appreciated - thanks.
 
parki...
 

________________________________

From: Clinton Begin [mailto:clinton.begin@gmail.com] 
Sent: Wednesday, August 06, 2008 11:16 AM
To: user-java@ibatis.apache.org
Subject: Re: Thread starvation - pool / Throttle issue?


Ah, if you're using Spring, then yes, it will take care of resource
allocation.  But your statement was: "but my understanding is that the
DBCP connection pool handles all that for me (?)", which is not the
case.

Clinton

On Wed, Aug 6, 2008 at 7:57 AM, Brian Parkinson <parki@avaning.com>
wrote:
>
> HI Clinton:
>  
> Have upgraded, and am refactoring some of my iBATIS code. You write:
>  
> "Pools handle closing connections, but you still have to call .close
(or some higher level delegating method) to return the connection to the
pool.  The rules are always the same... if you open it / start it /
retrieve it, then you must close it / stop it / return it... "
>  
> Below is an example Dao method implementation - my understanding
(wrong, it would appear) is that the SqlMapClientDaoSupport takes care
of ope/start/retrieve and close/stop/return.
>  
> Do I need to enclose my call to getSqlMapClientTemplate().update(...)
in a try/catch with open/close?
>  
> Thanks again - looks like homing in on the issue.
> Cheers,
>  
> parki...
>  
> --- x8 snip
>  
> public class AlertDao extends SqlMapClientDaoSupport implements
IAlertDao
> {
>  public Acknowledgement acknowledgeAlert(String thermostatIdentifier,
String acknowledgeRef,
>   boolean remindMeLater) throws Exception
>  {
>   AlertEntry alertEntry = new AlertEntry(thermostatIdentifier,
acknowledgeRef);
>   
>   getSqlMapClientTemplate().update("AlertMessage.updateByAlertEntry",
alertEntry);
>  
>   Acknowledgement acknowledgedSet = new Acknowledgement();
>   acknowledgedSet.setThermostatIdentifier(thermostatIdentifier);
>   acknowledgedSet.setAcknowledgeRef(acknowledgeRef);
>   acknowledgedSet.setRemindMeLater(remindMeLater);
>   
>   return acknowledgedSet;
>  }
>  
> ________________________________
> From: Clinton Begin [mailto:clinton.begin@gmail.com]
> Sent: Wednesday, August 06, 2008 9:52 AM
> To: user-java@ibatis.apache.org
> Subject: Re: Thread starvation - pool / Throttle issue?
>
> Pools handle closing connections, but you still have to call .close
(or some higher level delegating method) to return the connection to the
pool.  The rules are always the same... if you open it / start it /
retrieve it, then you must close it / stop it / return it...
>
> That said, upgrade to 2.3.3.  Then you'll more easily find the true
root cause of your issue, as all of the Throttles have been removed for
this very reason.  You'll likely get a complaint about no more
connections, or a DB deadlock.
>
> Clinton
>
> On Wed, Aug 6, 2008 at 7:18 AM, Brian Parkinson <parki@avaning.com>
wrote:
>>
>> HI Nicholoz  - looked at that thread - thx.
>>  
>> A key issue seems to be not closing connections, but my understanding
is that the DBCP connection pool handles all that for me (?).
>>  
>> The Dao implementation is pretty simple - I'm not explicitly
declaring transations, since using Spring transaction stuff and so each
Dao method looks like below.
>>  
>> Should I be explicitly handling transations stuff, and placing
everything inside try/catch/finally blocks? My understaniding was that
the Spring SqlMapClientDaoSupport did that for me.
>> public class AlertDao extends SqlMapClientDaoSupport implements
IAlertDao
>> {
>>  public Acknowledgement acknowledgeAlert(String thermostatIdentifier,
String acknowledgeRef,
>>   boolean remindMeLater) throws Exception
>>  {
>>   AlertEntry alertEntry = new AlertEntry(thermostatIdentifier,
acknowledgeRef);
>>   
>>   getSqlMapClientTemplate().update("AlertMessage.updateByAlertEntry",
alertEntry);
>>  
>>   Acknowledgement acknowledgedSet = new Acknowledgement();
>>   acknowledgedSet.setThermostatIdentifier(thermostatIdentifier);
>>   acknowledgedSet.setAcknowledgeRef(acknowledgeRef);
>>   acknowledgedSet.setRemindMeLater(remindMeLater);
>>   
>>   return acknowledgedSet;
>>  }
>> ... ETC ...
>> }
>> The Spring declaration:
>>  
>>  <bean id="txManager"
class="org.springframework.jdbc.datasource.DataSourceTransactionManager"
>
>>   <property name="dataSource" ref="dataSource"/>
>>  </bean>
>>  
>>  <tx:advice id="txAdvice" transaction-manager="txManager">
>>   <tx:attributes>
>>    <tx:method name="get*" read-only="true" />
>>    <tx:method name="*" />
>>   </tx:attributes>
>>  </tx:advice>
>>  
>>  <aop:config>
>>   <aop:pointcut id="daoServiceOperation" expression="execution(*
com.ecobee.foundation.dao.ibatis.*.*(..))" />
>>   <aop:advisor advice-ref="txAdvice"
pointcut-ref="daoServiceOperation" />
>>  </aop:config>
>>  
>> Appreciated - regards -
>>  
>> parki...
>>  
>> ________________________________
>> From: Nicholoz Koka Kiknadze [mailto:kiknadze@gmail.com]
>> Sent: Wednesday, August 06, 2008 8:56 AM
>> To: user-java@ibatis.apache.org
>> Subject: Re: Thread starvation - pool / Throttle issue?
>>
>> Have a look at this thread:
>>
>> http://www.mail-archive.com/user-java@ibatis.apache.org/msg11828.html
>>
>> Good luck
>>
>> On Wed, Aug 6, 2008 at 4:47 PM, Brian Parkinson <parki@avaning.com>
wrote:
>>>
>>> Hello:
>>>
>>> So, I have things up and running under Java and iBATIS, but running
into
>>> some starvation issue, and my server is locking up. When I dump
threads,
>>> I see a bunch that are waiting for the connnection pool (see output
#1
>>> below) and as well, a bunch that are waiting on Throttle.increment
(see
>>> output #2).
>>>
>>> Has anyone see anything similar?
>>>
>>> I am stumped right now - looking for ANY hints to help me track down
>>> (and fix :) what is going on - I don't know databases all that well,
so
>>> help appreciated greatly. First up, I'm going to upgrade to latest
>>> version of iBATIS, but thinking I might have something wrong in my
>>> thread pool setup.
>>>
>>> The pool setup:
>>>
>>>        <bean id="mapConfig"
>>> class="org.springframework.core.io.ClassPathResource">
>>>                <constructor-arg>
>>>
>>> <value>com/ecobee/foundation/dao/ibatis/SqlMapConfig.xml</value>
>>>                </constructor-arg>
>>>        </bean>
>>>
>>>        <bean id="dataSource"
>>> class="org.apache.commons.dbcp.BasicDataSource"
destroy-method="close">
>>>                <property name="driverClassName"
>>> value="com.mysql.jdbc.Driver" />
>>>                <property name="url" value="jdbc:mysql:///ecobee" />
>>>                <property name="username" value="XXX" />
>>>                <property name="password" value="XXX" />
>>>                <property name="initialSize" value="10" />
>>>                <property name="maxActive" value="100" />
>>>                <property name="maxIdle" value="10" />
>>>        </bean>
>>>
>>>        <bean id="sqlMapClient"
>>> class="org.springframework.orm.ibatis.SqlMapClientFactoryBean">
>>>                <property name="dataSource" ref="dataSource" />
>>>                <property name="configLocation" ref="mapConfig" />
>>>        </bean>
>>>
>>> I currently have no <settings> element in my SqlMapConfig.xml file,
so
>>> running with those defaults.
>>>
>>> Any help is greatly appreciated - I am mystified.
>>>
>>> I am using iBATIS 2.3.0.667 and commons dbcp 1.2.2, and running
MySQL
>>> 5.0.32.
>>>
>>> Off to upgrade to latest iBATIS as a start -
>>>
>>> Cheers,
>>>
>>> parki...
>>>
>>> --- x8 snip
>>>
>>> Output #1:
>>>
>>> Thread: Thread[pool-1-thread-121,5,main]=
>>>  -- java.lang.Object.wait(Native Method)
>>>  -- java.lang.Object.wait(Object.java:474)
>>>  --
>>>
org.apache.commons.pool.impl.GenericObjectPool.borrowObject(GenericObjec
>>> tPool.java:810)
>>>  --
>>>
org.apache.commons.dbcp.PoolingDataSource.getConnection(PoolingDataSourc
>>> e.java:96)
>>>  --
>>>
org.apache.commons.dbcp.BasicDataSource.getConnection(BasicDataSource.ja
>>> va:880)
>>>  --
>>>
org.springframework.jdbc.datasource.DataSourceTransactionManager.doBegin
>>> (DataSourceTransactionManager.java:200)
>>>  --
>>>
org.springframework.transaction.support.AbstractPlatformTransactionManag
>>> er.getTransaction(AbstractPlatformTransactionManager.java:377)
>>>  --
>>>
org.springframework.transaction.interceptor.TransactionAspectSupport.cre
>>> ateTransactionIfNecessary(TransactionAspectSupport.java:261)
>>>  --
>>>
org.springframework.transaction.interceptor.TransactionInterceptor.invok
>>> e(TransactionInterceptor.java:101)
>>>  --
>>>
org.springframework.aop.framework.ReflectiveMethodInvocation.proceed(Ref
>>> lectiveMethodInvocation.java:171)
>>>  --
>>>
org.springframework.aop.interceptor.ExposeInvocationInterceptor.invoke(E
>>> xposeInvocationInterceptor.java:89)
>>>  --
>>>
org.springframework.aop.framework.ReflectiveMethodInvocation.proceed(Ref
>>> lectiveMethodInvocation.java:171)
>>>  --
>>>
org.springframework.aop.framework.JdkDynamicAopProxy.invoke(JdkDynamicAo
>>> pProxy.java:204)
>>>  -- $Proxy2.saveLogSet(Unknown Source)
>>>  --
>>>
com.ecobee.communicator.rest.restlet.LogRestlet.doPost(LogRestlet.java:7
>>> 6)
>>>  --
>>>
com.ecobee.communicator.rest.RestletManager.handleRequest(RestletManager
>>> .java:195)
>>>  --
>>>
com.ecobee.communicator.engine.EngineRequest.handleRequest(EngineRequest
>>> .java:112)
>>>  -- sun.reflect.GeneratedMethodAccessor338.invoke(Unknown Source)
>>>  --
>>>
sun.reflect.DelegatingMethodAccessorImpl.invoke(DelegatingMethodAccessor
>>> Impl.java:25)
>>>  -- java.lang.reflect.Method.invoke(Method.java:585)
>>>  --
>>>
com.whatevernot.engine.standard.StateRunnable.run(StateRunnable.java:56)
>>>  --
>>>
java.util.concurrent.ThreadPoolExecutor$Worker.runTask(ThreadPoolExecuto
>>> r.java:650)
>>>  --
>>>
java.util.concurrent.ThreadPoolExecutor$Worker.run(ThreadPoolExecutor.ja
>>> va:675)
>>>  -- java.lang.Thread.run(Thread.java:595)
>>>
>>> Output #2:
>>>
>>> Thread: Thread[pool-1-thread-613,5,main]=
>>>  -- java.lang.Object.wait(Native Method)
>>>  -- java.lang.Object.wait(Object.java:474)
>>>  -- com.ibatis.common.util.Throttle.increment(Throttle.java:70)
>>>  -- com.ibatis.common.util.ThrottledPool.pop(ThrottledPool.java:57)
>>>  --
>>>
com.ibatis.sqlmap.engine.impl.SqlMapExecutorDelegate.popSession(SqlMapEx
>>> ecutorDelegate.java:933)
>>>  --
>>>
com.ibatis.sqlmap.engine.impl.SqlMapSessionImpl.<init>(SqlMapSessionImpl
>>> .java:51)
>>>  --
>>>
com.ibatis.sqlmap.engine.impl.SqlMapClientImpl.getLocalSqlMapSession(Sql
>>> MapClientImpl.java:259)
>>>  --
>>>
com.ibatis.sqlmap.engine.impl.SqlMapClientImpl.startBatch(SqlMapClientIm
>>> pl.java:161)
>>>  --
com.ecobee.foundation.dao.ibatis.LogDao.saveLogSet(LogDao.java:22)
>>>  -- sun.reflect.GeneratedMethodAccessor341.invoke(Unknown Source)
>>>  --
>>>
sun.reflect.DelegatingMethodAccessorImpl.invoke(DelegatingMethodAccessor
>>> Impl.java:25)
>>>  -- java.lang.reflect.Method.invoke(Method.java:585)
>>>  --
>>>
org.springframework.aop.support.AopUtils.invokeJoinpointUsingReflection(
>>> AopUtils.java:301)
>>>  --
>>>
org.springframework.aop.framework.ReflectiveMethodInvocation.invokeJoinp
>>> oint(ReflectiveMethodInvocation.java:182)
>>>  --
>>>
org.springframework.aop.framework.ReflectiveMethodInvocation.proceed(Ref
>>> lectiveMethodInvocation.java:149)
>>>  --
>>>
org.springframework.transaction.interceptor.TransactionInterceptor.invok
>>> e(TransactionInterceptor.java:106)
>>>  --
>>>
org.springframework.aop.framework.ReflectiveMethodInvocation.proceed(Ref
>>> lectiveMethodInvocation.java:171)
>>>  --
>>>
org.springframework.aop.interceptor.ExposeInvocationInterceptor.invoke(E
>>> xposeInvocationInterceptor.java:89)
>>>  --
>>>
org.springframework.aop.framework.ReflectiveMethodInvocation.proceed(Ref
>>> lectiveMethodInvocation.java:171)
>>>  --
>>>
org.springframework.aop.framework.JdkDynamicAopProxy.invoke(JdkDynamicAo
>>> pProxy.java:204)
>>>  -- $Proxy2.saveLogSet(Unknown Source)
>>>  --
>>>
com.ecobee.communicator.rest.restlet.LogRestlet.doPost(LogRestlet.java:7
>>> 6)
>>>  --
>>>
com.ecobee.communicator.rest.RestletManager.handleRequest(RestletManager
>>> .java:195)
>>>  --
>>>
com.ecobee.communicator.engine.EngineRequest.handleRequest(EngineRequest
>>> .java:112)
>>>  -- sun.reflect.GeneratedMethodAccessor338.invoke(Unknown Source)
>>>  --
>>>
sun.reflect.DelegatingMethodAccessorImpl.invoke(DelegatingMethodAccessor
>>> Impl.java:25)
>>>  -- java.lang.reflect.Method.invoke(Method.java:585)
>>>  --
>>>
com.whatevernot.engine.standard.StateRunnable.run(StateRunnable.java:56)
>>>  --
>>>
java.util.concurrent.ThreadPoolExecutor$Worker.runTask(ThreadPoolExecuto
>>> r.java:650)
>>>  --
>>>
java.util.concurrent.ThreadPoolExecutor$Worker.run(ThreadPoolExecutor.ja
>>> va:675)
>>>  -- java.lang.Thread.run(Thread.java:595)
>>
>



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