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:[EMAIL PROTECTED] Sent: Tuesday, September 05, 2006 10:22 AM To: [email protected] 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:[EMAIL PROTECTED] >> Sent: Sunday, September 03, 2006 11:51 PM >> To: [email protected] >> 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 <[EMAIL PROTECTED]> 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:[EMAIL PROTECTED] >>> Sent: Tuesday, August 29, 2006 1:23 AM >>> To: [email protected] >>> 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. >
