Re: out of memory error

I've now conducted some memory profiling tests.
The memory usage appears flat over large numbers of requests and/or  
high concurrency, detailed results follow.

The tests consist of sending repeated HTTP requests, using Apache  
Bench, to the ObjectBox Servlet. The target program uses several  
o:Lib types, Java and database extensions, and an XSL transformation  
of the result XML - it could be said to be of medium complexity.

First test
10000 requests total, with 4 concurrent requests at any time.
Output from 'top' at the start, middle and end of tests:
   PID COMMAND      %CPU   TIME   #TH #PRTS #MREGS RPRVT  RSHRD   
RSIZE  VSIZE
   136 java        43.6%  2:15:39  44   830   324   100M+ 4.88M  80.1M 
+  743M+
   136 java        62.8%  2:17:52  44   837   315   101M  4.88M  80.9M 
+  742M
   136 java         0.2%  2:18:33  44   837   314   101M  4.88M   
80.9M   742M

Second test
1 million requests, with concurrency of 4, over 48 hours. The memory  
used by the VM stayed at near 100Mb, +/- 2 Mb, during most of the  
test. Some time after 700000 requests it rose by around 20Mb. After  
finishing the tests, the VM released the majority of memory in use  
and shrunk its footprint to 24Mb, about one fifth of the maximum in use.
start 1000000 requests
   136 java        58.5%  2:18:41  44   837   314   101M  4.88M   
80.9M   742M
   136 java        62.4%  2:19:13  44   837   316   101M  4.88M   
80.1M   742M
after 100000:
   136 java        69.8%  3:41:21  44   840   318   103M+ 1.12M  73.2M 
+  746M+
   136 java        76.9%  3:42:02  44   840   314   101M- 1.12M   
71.1M-  742M-
after 200000:
   136 java        84.7%  4:33:34  44   841   316   100M- 1.12M   
70.9M-  742M
after 400000:
   136 java        60.2%  9:35:36  44   843   318   103M+ 1016K  90.1M 
+  747M+
   136 java        70.2%  9:35:42  44   843   314   100M  1016K   
87.2M-  742M-
after 600000:
   136 java        48.5% 14:52:42  44   848   317   115M+  580K-  102M 
+  747M+
   136 java        42.2% 14:53:25  44   848   314   108M   584K   
96.5M   742M
after 700000:
   136 java        68.0% 18:58:31  44   848   314   113M   588K   105M 
+  742M-
after 900000:
   136 java        64.0% 28:54:15  44   848   317   130M+  588K   122M 
+  747M+
   136 java        62.6% 28:54:28  44   848   314   126M   588K    
118M   742M
finish 1000000 requests
   136 java         0.2% 29:58:53  44   848   316   126M  1.99M    
119M   742M
   136 java         0.1% 29:59:19  44   848   313  86.4M- 1.02M-  
84.8M-  742M
   136 java         3.6% 30:00:19  44   848   317  24.8M   620K   
23.6M   742M


Whereas no significant growth in memory consumption can be seen,  
memory profiling indicates an increase in DynamicFunction and Type[]  
objects by just under 500000 new objects (each) after 1.2 million  
requests. This would indicate a leak - I'm currently investigating  
the source and a possible solution.


regards,

/m


On 29 Jul 2005, at 21:13, Laura Demange wrote:

>     I have been having problems with out of memory errors using  
> o:XML in web services using axis in tomcat. The web services are  
> written in java and work as follows: When one of its methods is  
> called, it gets the corresponding o:XML program (using  
> ProgramProxy), adds java and database extensions, then compiles the  
> program and runs it with a custom result handler.  The out of  
> memory error occurs after numerous/frequent requests to the service.
>
>    I was just wondering if anyone else has had a similar problem,  
> or if there is a known memory leak in o:XML? Any ideas or help  
> would be appreciated. I can provide more info and/or source code if  
> needed.
>
>
>
> Thanks,
>
> Laura
>