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 <[EMAIL PROTECTED]> 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:[EMAIL PROTECTED]
Sent: Tue 3/6/2007 10:11 AM
To: [email protected]
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: '[email protected]'
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: '[email protected]'
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: '[email protected]'
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: '[email protected]'
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$SynchronizedRandomAccessList
-----pool of com.ibatis.common.util.ThrottledPool
------requestPool of com.ibatis.sqlmap.engine.impl.SqlMapExecutorDelega te
------delegate of com.ibatis.sqlmap.engine.impl.SqlMapClientImpl
-------client of
com.ibatis.dao.engine.transaction.sqlmap.SqlMapDaoTransactionManager
--------transactionManager of com.ibatis.dao.engine.impl.DaoContext
---------[0] of java.lang.Object[11]
----------elementData of java.util.ArrayList
-----------value of java.lang.ThreadLocal$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: '[email protected]'
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
