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From "Fateev, Maxim" <fat...@amazon.com>
Subject RE: Paging support
Date Tue, 05 Sep 2006 17:35:58 GMT
Rob,
Would you give overview of the proposed design for the paging support in ActiveMQ? The AMQ-845
doesn't provide any specifics.

-----Original Message-----
From: Rob Davies [mailto:rajdavies@gmail.com] 
Sent: Tuesday, September 05, 2006 10:22 AM
To: activemq-users@geronimo.apache.org
Subject: Re: Paging support

A message reference is kept in memory (which consists of a messageId and information like
sequence Id to enable faster retrieval from storage).
There is some work currently in progress in enable paging support in ActiveMQ - see http://issues.apache.org/activemq/browse/AMQ-845


On 5 Sep 2006, at 18:07, pradeep wrote:

>
> Maxim,
>
> Can you clarify this
> Are you storing just the message id or the whole message in memory?  
> Your
> help will be highly appreciated.
>
> Thanks
> pradeep
>
>
> Fateev, Maxim wrote:
>>
>> It would be interesting to see some numbers about memory utilization 
>> per message in backlog.
>>
>> IMHO the main problem with keeping references in memory is that it 
>> needs recovery phase on broker startup. It can take a while when 
>> backlog is really big.
>>
>> -----Original Message-----
>> From: James Strachan [mailto:james.strachan@gmail.com]
>> Sent: Sunday, September 03, 2006 11:51 PM
>> To: activemq-users@geronimo.apache.org
>> Subject: Re: Paging support
>>
>> Note that MessageReferences != message contents; they are mostly just 
>> a MessageId which is pretty small.
>>
>> On 8/29/06, Fateev, Maxim <fateev@amazon.com> wrote:
>>> AFAIK messages are moved from journal to permantent storage
>>> (JDBC) on
>>> every checkpoint. The problem is that references for every message 
>>> are still kept in memory.
>>> IMHO it is inherent limitation of MessageStore API as it is defined 
>>> now.
>>> The only way to get message is by id. And the only way to have id is 
>>> to keep it in memory.
>>> I'm looking into changing MessageStore API to one that instead of
>>>
>>> Message         getMessage(MessageId identity)
>>>
>>> Would provide
>>>
>>> Message getNextMessage()
>>>
>>> method eliminating need to keep references in memory.
>>>
>>>
>>>
>>> -----Original Message-----
>>> From: Anders Bengtsson [mailto:ndrsbngtssn@yahoo.se]
>>> Sent: Tuesday, August 29, 2006 1:23 AM
>>> To: activemq-users@geronimo.apache.org
>>> Subject: Re: Paging support
>>>
>>>
>>>
>>> gnodet wrote:
>>>>
>>>> If you don' t use any persistent store, messages must be kept in 
>>>> memory, so you are obvisouly limited by the available mem.
>>>>
>>>
>>> Yes, this is what I would expect.
>>>
>>>
>>>
>>>> If you use a jdbc store, messages can be removed from memory and 
>>>> store for later consumption.
>>>>
>>>
>>> Yes, except it doesn't actually work!
>>>
>>> It writes things to the store, but it is still very much limited by 
>>> memory for some reason. (Someone reported this as AMQ-845 earlier, 
>>> but with no response).
>>>
>>> --
>>> View this message in context:
>>> http://www.nabble.com/Paging-support-tf2163517.html#a6034790
>>> Sent from the ActiveMQ - User forum at Nabble.com.
>>>
>>
>>
>> --
>>
>> James
>> -------
>> http://radio.weblogs.com/0112098/
>>
>>
>
> --
> View this message in context: http://www.nabble.com/Paging-support-
> tf2163517.html#a6156162
> Sent from the ActiveMQ - User forum at Nabble.com.
>

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