> -----Original Message----- > From: Gerhard Adam [mailto:[EMAIL PROTECTED] > Sent: Friday, November 09, 2007 1:57 PM > To: IBM-MAIN@BAMA.UA.EDU > Subject: Re: Performance comparison: Hiperbatch, BLSR, SMB? > > Unfortuanately I haven't looked up this stuff in a long time, so I might > be wrong. But IIRC, Hiperbatch is intended for sequential access and is > counter-productive for random files. Since it uses a Most Recently Used > algorithm (instead of LRU), the intent was to ensure that the most recent > access to a record was the most eligible for getting discarded from memory > (since this represented the last reader of the data).
Well, I don't know about your memory, but the latest version does indeed support random access, AFTER the DLF has been loaded sequentially. Don't know what algorithm it uses, but my SMF gurus tell me they can prove it is being used, and in fact the batch jobs run longer if anything happens to Hiperbatch, so I think it's working. Our access is almost all random. > The whole point was to avoid having records discarded because of age just > ahead of someone that was reading the file sequentially. > > Also, another point was that the I/O counts were unaffected since the > application was unaware that it was using Hiperbatch, so that information > is largely irrelevant. I didn't know that, but it makes sense. Thanks. > Anyway ... here's hoping my memory isn't completely gone Not completely. :) Peter This message and any attachments are intended only for the use of the addressee and may contain information that is privileged and confidential. If the reader of the message is not the intended recipient or an authorized representative of the intended recipient, you are hereby notified that any dissemination of this communication is strictly prohibited. If you have received this communication in error, please notify us immediately by e-mail and delete the message and any attachments from your system. ---------------------------------------------------------------------- For IBM-MAIN subscribe / signoff / archive access instructions, send email to [EMAIL PROTECTED] with the message: GET IBM-MAIN INFO Search the archives at http://bama.ua.edu/archives/ibm-main.html
