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From "Clinton Begin" <clinton.be...@gmail.com>
Subject Re: What is RequestScope used for?
Date Thu, 08 Mar 2007 17:06:12 GMT
There should be ONE instance of SQLMapClientImpl.  And there's only ONE
thing that creates it....a call to SqlMapClientBuilder.buildSqlMapClient();

Now the DAO framework builds that instance for you, but the
DAOManagerBuilder works the same way...you get only one instance per call to
buildDaoManager()  (or whatever the method is called).

I'm betting you have some service class or something that's madly
instantiating or initializing DaoManagers or SqlMapClients .... or perhaps
Spring containers....something is messed up wherever you configure your
classes.

Clinton

On 3/8/07, Daniel Kalcevich <DKalcevich@marketlinx.com> wrote:
>
> Clinton,
>
> What do you mean?  What would cause that type of condition in the SQL
> Maps?
>
> Daniel
>
> ________________________________
>
> From: Clinton Begin [mailto:clinton.begin@gmail.com]
> Sent: Thu 3/8/2007 8:50 AM
> To: user-java@ibatis.apache.org
> Subject: Re: What is RequestScope used for?
>
>
> >>  The snapshot I took showed 402 objects of the SqlMapClientImpl a
>
> It's now clear to me that you're building more than one SQL Map
> instance...possibly one per thread.
>
> It's not your transactional code, it's wherever you're building your
> DAOManager or your SqlMapClient.
>
> Clinton
>
>
> On 3/8/07, Daniel Kalcevich <DKalcevich@marketlinx.com> wrote:
>
>         OK, I went ahead and changed the places where DaoManager is used
> and made the logic something like the following:
>
>         try {
>              DAOManager.startTransaction();
>
>              ...something...
>
>             DAOManager.commitTransaction ();
>         } finally {
>            DAOManager.endTransaction();
>         }
>
>         After making those changes, I am still seeing those RequestScope
> objects in Memory.  The snapshot I took showed 402 objects of the
> SqlMapClientImpl and 205, 824 objects of the Request Scope.
>
>         Is there any place else I should look to help with these
> RequestScope Objects?
>
>         Daniel
>
>         ________________________________
>
>         From: Kalcevich, Daniel [mailto:dkalcevich@firstam.com ]
>         Sent: Tue 3/6/2007 10:11 AM
>         To: user-java@ibatis.apache.org
>         Subject: RE: What is RequestScope used for?
>
>
>
>         Clinton,
>
>
>
>         Thanks for the help.  I will change the DaoManager to handle the
> transactions at the points in the code where I am using them.  That way,
> should I perform any calls that require transactions, they will already be
> there.  I'll try it out and let you know if I run into any more problems.
>
>
>
>         Daniel
>
>
>
>         ________________________________
>
>         >> With regards to the DAO framework side of it, could I just wrap
> any calls to the SQL maps
>         >> with a try/finally that always calls the endTransaction()
> method on the SqlMapClient?
>
>         No, don't do that.  The iBATIS DAO framework is very similar to
> Spring.  It handles the transactions inside the DAOs for you.  But the
> consumer of the DAOs shoudl be starting and ending transactions on the
> DaoManager within a try/finally block.
>
>         >> Because all of them are only SELECT statements, I don't really
> need transactions inside the library itself.
>         >> Or do I actually need to insert the startTransaction() and
> commitTransaction() methods regardless?
>
>         No, you don't need start/commit/end if you're just doing
> selects.  You can just call the DAO methods.  Just make sure you're not
> calling start without a corresponding end....
>
>         Clinton
>
>         ________________________________
>
>         From: Kalcevich, Daniel
>         Sent: Tuesday, March 06, 2007 9:46 AM
>         To: 'user-java@ibatis.apache.org'
>         Subject: RE: What is RequestScope used for?
>
>
>
>         Clinton,
>
>
>
>         Yes, the applications run inside the same JVM.
>
>
>
>         As for the Spring, I have already posted something to the Spring
> forum verifying that the way in which we use them are correct, and they
> appear to be.
>
>
>
>         With regards to the DAO framework side of it, could I just wrap
> any calls to the SQL maps with a try/finally that always calls the
> endTransaction() method on the SqlMapClient?  Because all of them are only
> SELECT statements, I don't really need transactions inside the library
> itself.  Or do I actually need to insert the startTransaction() and
> commitTransaction() methods regardless?
>
>
>
>         Daniel
>
>
>
>         ________________________________
>
>         Is this all in the same VM?
>
>         Spring is the recommended DAO solution and is probably the way
> that at least 50% of iBATIS users use it.  You don't need to worry about
> transactions at all with Spring, it will take care of it (as far as iBATIS
> is concerned at least).  Have a look at the spring docs to ensure that
> you're using it the right way.
>
>         I agree that you should start by looking at the other part that
> uses your own lib with iBATIS DAO.  With iBATIS DAO you need to ensure
> you're starting and ending transactions in a try/finally block just like
> with SqlMapClient.
>
>         Cheers,
>         Clinton
>
>
>
>         ________________________________
>
>         From: Kalcevich, Daniel
>         Sent: Tuesday, March 06, 2007 9:29 AM
>         To: 'user-java@ibatis.apache.org '
>         Subject: RE: What is RequestScope used for?
>
>
>
>         Clinton,
>
>
>
>         Thanks for the response.  Now with regards to the Transactions...
> our application uses SQL Maps in two different ways.
>
>
>
>         1.      Within Spring inside the Web App - We use transactions
> within Spring, thus SQL maps should not be using the transactions.
>         2.      A library we developed that the Web App uses - This uses
> the DAO framework and SQL Maps internally, but only retrieves information
> from the DB, not inserts.
>
>
>
>         For the Transactions, do I have to declare them explicitly in both
> places, or do you think it would be better to address the standalone library
> first?
>
>
>
>         Daniel
>
>
>
>         ________________________________
>
>         Yep, you have a leak and it is RequestScope related...but it's
> likely not an ibatis bug...
>
>         It's more likely that you're not ending transactions properly.
>
>         try {
>           sqlMapClient.startTransaction ();
>           ///... do work
>         } finally {
>           sqlMapClient.endTransaction();
>         }
>
>         Clinton
>
>
>
>         ________________________________
>
>         From: Kalcevich, Daniel
>         Sent: Tuesday, March 06, 2007 8:18 AM
>         To: ' user-java@ibatis.apache.org'
>         Subject: RE: What is RequestScope used for?
>
>
>
>         OK, upon looking at the Yourkit, I am showing the number of
> objects in memory as the following:
>
>
>
>         -          com.ibatis.sqlmap.engine.impl.SqlMapClientImpl - 212
> objects with a total retained size in memory of 31.38MB
>
>         -          com.ibatis.sqlmap.engine.scope.RequestScope - 108, 544
> objects with a total retained size in memory of 16.49MB.
>
>         -          com.ibatis.sqlmap.engine.scope.SessionScope - 27,136
> objects with a total retained size in memory of 3.03 MB.
>
>
>
>         Do those numbers make sense?  I only question it because with
> every snapshot of the memory I have taken along the way, the
> RequestScope/SessionScope objects keep increasing.
>
>
>
>         Daniel
>
>
>
>         ________________________________
>
>         From: Kalcevich, Daniel
>         Sent: Tuesday, March 06, 2007 7:04 AM
>         To: 'user-java@ibatis.apache.org '
>         Subject: RE: What is RequestScope used for?
>
>
>
>         I found about this RequestScope through the profiler
> YourKit.  Here is the trail that references the IBatis objects.
>
>
>
>         map of com.ibatis.sqlmap.engine.scope.RequestScope
>
>         --[121] of java.lang.Object[513]
>
>         ---elementData of java.util.ArrayList
>
>         ----list of java.util.Collections$SynchronizedRandomAccessList
>
>         -----pool of com.ibatis.common.util.ThrottledPool
>
>         ------requestPool of
> com.ibatis.sqlmap.engine.impl.SqlMapExecutorDelega te
>
>         ------delegate of com.ibatis.sqlmap.engine.impl.SqlMapClientImpl
>
>         -------client of
> com.ibatis.dao.engine.transaction.sqlmap.SqlMapDao TransactionManager
>
>         --------transactionManager of
> com.ibatis.dao.engine.impl.DaoContext
>
>         ---------[0] of java.lang.Object[11]
>
>         ----------elementData of java.util.ArrayList
>
>         -----------value of java.lang.ThreadLocal$ThreadLocalMap$Entry
>
>         ------------[1442] of java.lang.ThreadLocal$ThreadLocalMap$Entry
> [2049]
>
>         -------------table of java.lang.ThreadLocal$ThreadLocalMap
>
>         --------------threadLocals of java.lang.Thread [Stack Local,
> Thread]
>
>
>
>
>
>         The reason I thought it might be contributing to a memory leak was
> the fact that at every snapshot I take, the number of HashMaps continues to
> increase without going down.  Then when I look at what it is referring to,
> it points to the RequestScope.
>
>
>
>         While looking in the trace, I saw that it was referencing the
> DaoContext's transaction Manager.  Could the Transaction Manager be playing
> a part in this?  My application uses Spring with SQL Maps, but a library we
> wrote uses the DAO Framework specifically.  The Spring application does not
> use it.  I think that is worth looking into, given what I see in the
> profiler.
>
>
>
>         Daniel
>
>
>
>
>
>         ________________________________
>
>         From: Kalcevich, Daniel
>         Sent: Monday, March 05, 2007 11:37 AM
>         To: 'user-java@ibatis.apache.org '
>         Subject: What is RequestScope used for?
>
>
>
>         Hello,
>
>
>
>         I have a Spring, Struts, SQL Map application that runs on
> JBoss/Tomcat.  And while going through a profiler, I am seeing that there
> are several instances of " com.ibatis.sqlmap.engine.scope.RequestScope".  What
> is that object used for?  The reason I ask is that I am trying to track down
> a memory leak and am wondering if this class is possibly part of the
> cause?  Any help is greatly appreciated.  Thank you.
>
>
>
>         Daniel
>
>
>
>
>
>
>

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