2 Replies Latest reply on Jul 23, 2012 3:59 AM by Andy Taylor

    Paging: 0-kB-page, deleting of page files, filling the queue from pages

    Leonid GL Newbie

      Hi all

       

      I want exactly to understand how paging works. Namely:

       

      • What for is the 0-kB page file in the paging directory? Sometimes there are multiple 0-files available.
      • When will be the page file deleted? My assumption is, AFTER the file is loaded into the queue AND acknowledged by a consumer. With other words, it does still exist even if its messages were consumed. Am I right?
      • My test queue is of size 409600 byte (400 kB). If the queue is durable, then it can contain only  3 messages (97 kB each) before paging starts (after third message 0-file will be created), if the same queue is undurable it can contains 5 same messages.How to explain this difference?
      • When the queue is empty and everything is acknowledged, depaging starts. How many files will be loaded into the queue? My assumption is only one, even if there is much more place in the queue. I have tested it and it seems to be right, but sometimes more than one file is deleted!

       

       

       

      Unfortunately user manual doesn’t answer it. Thank you for all kind of help.

        • 1. Re: Paging: 0-kB-page, deleting of page files, filling the queue from pages
          Leonid GL Newbie

          37 Views but no replies...

           

          is my description not enough exact or confusing?

          • 2. Re: Paging: 0-kB-page, deleting of page files, filling the queue from pages
            Andy Taylor Master

            What for is the 0-kB page file in the paging directory? Sometimes there are multiple 0-files available.

            page files are created in advance for performance reasons

            When will be the page file deleted? My assumption is, AFTER the file is loaded into the queue AND acknowledged by a consumer. With other words, it does still exist even if its messages were consumed. Am I right?

            paged files are deleted once acked, altho there is a bug in older versions where files are not deleted

            My test queue is of size 409600 byte (400 kB). If the queue is durable, then it can contain only  3 messages (97 kB each) before paging starts (after third message 0-file will be created), if the same queue is undurable it can contains 5 same messages.How to explain this difference?

            persistant and non persistant messages are handled differently, since persistant message are already written to disc less information is paged.

            When the queue is empty and everything is acknowledged, depaging starts. How many files will be loaded into the queue? My assumption is only one, even if there is much more place in the queue. I have tested it and it seems to be right, but sometimes more than one file is deleted!

            a whole page is depaged at a time, this will keep happening until the address max has been reached.

            37 Views but no replies...

             

            is my description not enough exact or confusing?

            Give us a chance to reply, many devs are on vacation and we have paying support customers, remember this is free support.