IDMS

FW: Journal Offload with Fastaccess

  • 1.  FW: Journal Offload with Fastaccess

    Posted Oct 19, 2009 07:55 AM
    Hi David

    I ran a quick test to see if I was ""out of date"". No I am not. QSAM does
    still work but I was wrong about the Archive being the target for QSAM.
    It is actually the input disk journal.

    Command ===>
    1 RBN processed by OPEN for file J1JRNL
    30 QSAM BUFFERS will be used
    QSAM area is ARCHIVE.JOURNAL
    0 RBN processed by SKIP for file J1JRNL
    1 RBN processed by QSAM for file J1JRNL
    .
    .
    3 RBN processed by WRIT for file J1JRNL
    3 RBN processed by CLOS for file J1JRNL
    47,873 pages READ thru QSAM
    41 pages READ thru BDAM
    6 pages QSAM skipped
    30 QSAM BUFFERS used
    QSAM area is ARCHIVE.JOURNAL

    END OF JOURNAL ARCHIVE 2009-10-19-11.35.59.820515
    Status = 0 SQLSTATE = 00000

    Clearly the process is using QSAM instead of BDAM and it is the input
    disk journal which is getting the QSAM push.

    The question now is whether the advantages of using QSAM over BDAM have
    been eroded over the years by the advances in hardware and caching. It
    may well be that when I first tried this solution (in my youth) that the
    difference was very marked but that technology has made it redundant.
    Neither do I have any recollection of how I came up with 30 as a magic
    number.

    Chris