Persistence manager, large queues & out.of.memory

[delboypass]

I have come a cropper with the current system which I am building.

On one machine I am hosting a queue, on another machine I have a client which is writing to this queue.

I am trying some load tests so am writing 40,000 messages from the client to the queue.

This ends up with the client receiving an out-of memory-exception and the same on the client.

At this stage the queue has a fair few messages in it - about 30,000.

The problem is that it doesnt seem to recover from this.
If the server hosting the queue is then shut down and restarted - it shows the out-of-memory exception before completing the deployment.

This out of memory exception is thrown after/by when the persistence manager is started up.

What is the setup for the persistance manager. - currently I am writing the messages of the queue to a file so is hte persistence manager still holding a virtual memory copy of hte message as well and how do I stop this action!

Thanks for the help!

[genman]

How much memory are you running out of memory at?

Java usually only allows for 200MB at maximum, you can set this higher, to whatever your server allows.

[delboypass]

Is there a way that I can tell how much memory it is running out at.

How do i reset the memory to be higher running JBoss.
Do I need to use the -xm command when running java or is there a configuration change needed to be made.

What I was more concerned about was the operation of the persistence manager or why vast amounts of memory are consumed when writing a large amount of messages to a queue which is hosted on a file.

The reason i believe that the app is running out of memory is because somewhere these messages are not only being persisted in the dilesystem but also in memory (perhaps by the persistence manager).

Do you know about any of these things??
Cheers del.

[stephanenicoll]

test

[stephanenicoll]

1/ Check in the code if you close your JMS connections / sessions
2/ When Jboss starts, pending JMS messages are pooled in the cache. By default the size of this cache is 500/600 (Mo !!!!). I have decrased it to a more acceptalbe value (16/32 see the MessageCache bean in jbossmq-service.xml)

[stephanenicoll]

What version of JBoss are u using? If you use version 3.0.X, the CacheStore is mapped to some file by default (and not the DB)

[delboypass]

Using version 3.0.4

So pending messages are held in memory are you saying.
So that doesnt explain that when you restart the jboss application server when no meesages are pending that it also exhibits an out-of memory exception when the message queue (pesisted to disk) is full of around 40,000 messages.

So it looks like it is trying to read the persisted messages from the disk into memory on restart. Somewhere something is holding htese messages in memory which i think in turn is throwing the out of memory exception.

Ive checked the message cache as it says that if it is running out of memeory then messages in memory should be persisted to file. And this also isnt the case although ive havent played about with the messagecache size yet.

[stephanenicoll]

So that doesnt explain that when you restart the jboss application server when no meesages are pending that it also exhibits an out-of memory exception when the message queue (pesisted to disk) is full of around 40,000 messages.

Of course that does explain the OutOfMemory!!!

I wrote "When Jboss starts, pending JMS messages are pooled in the cache. By default the size of this cache is 500/600 (Mo !!!!). I have decrased it to a more acceptalbe value (16/32 see the MessageCache bean in jbossmq-service.xml)"

So when Jboss start, your 40.000 messages are pooled in the RAM!

[stephanenicoll]

So that doesnt explain that when you restart the jboss application server when no meesages are pending that it also exhibits an out-of memory exception when the message queue (pesisted to disk) is full of around 40,000 messages.

Of course that does explain the OutOfMemory!!!

I wrote "When Jboss starts, pending JMS messages are pooled in the cache. By default the size of this cache is 500/600 (Mo !!!!). I have decrased it to a more acceptalbe value (16/32 see the MessageCache bean in jbossmq-service.xml)"

So when Jboss start, your 40.000 messages are pooled in the RAM!

[delboypass]

Is there a way of turning off this cache.

Surely a better algorithm would be to look in the filesystem, do some kind of sort, pick up the required message rather than pooling all the messages into the cache. This means that queues sizes are limited by the size of the cache.

[smeg]

Indeed some rigourous load testing might have been
a good idea,
How do you achieve the same restriction in Version 2.4.4

Cheers

[adrian.brock]

There is no cache in jboss-2.4

Regards,
Adrian

[eusebio]

I've read somewhere in the docs that there is also a maximum number of messages in 2.4 (set at a static value of 1000) - is this correct?

Does this mean that you can only have 1000 messages on the server or does it mean 1000 per queue?

[adrian.brock]

I'm not aware of any such restriction.

As far as I know, the limit is OutOfMemory because
messages are not pushed to disk when memory is short.

Regards,
Adrian