Shared Memory segment (5 of them)

Hi gurus, Recently, I noticed 5 extra shared memory segments created in my Informix 7.30 UC7. What could have caused this and how to remove/prevent these segments from created again? AFAIK, more shared memory segments means less efficient shared memory usage. Am I right? Thank you in advance, Lawrence Choy Mobile: +6019-310-2658

In article <8gii9u$eep$1@news.xmission.com>, "Lawrence @ Maxis.Net" <lschoy@maxis.net.my> wrote: > > Hi gurus, > > Recently, I noticed 5 extra shared memory segments created in my Informix > 7.30 UC7. What could have caused this and how to remove/prevent these > segments from created again? AFAIK, more shared memory segments means less > efficient shared memory usage. Am I right? > Yes, you are right. To prevent them, figure out what the shared memory usage is right now in blocks and set SHMVIRTSIZE to that. Then set SHMTOTAL to that also, if you really want to stop the database from allocating more chunks. I wouldn't recommend it, though. I think you'd be better off setting SHMTOTAL to about 90% of physical memory on the box in blocks. What's happening is that while Informix is running, it's running out of memory, so it's allocating more. These extra chunks are less efficient, so if you set SHMVIRTSIZE to what Informix is going to ultimately need in advance, it won't have to allocate more. > Thank you in advance, > Lawrence Choy > Mobile: +6019-310-2658 > > -- # unrm / ksh: unrm: not found # man cpio Sent via Deja.com http://www.deja.com/ Before you buy.

"Lawrence @ Maxis.Net" wrote: > > Hi gurus, > > Recently, I noticed 5 extra shared memory segments created in my Informix > 7.30 UC7. What could have caused this and how to remove/prevent these > segments from created again? AFAIK, more shared memory segments means less > efficient shared memory usage. Am I right? > > Thank you in advance, > Lawrence Choy > Mobile: +6019-310-2658 Anytime Informix needs more virtual memory (sorting, etc.) then it currently has (SHMVIRTSIZE), it will grab more (SHMADD). Removing them is just a matter of running: onmode -F Increasing SHMVIRTSIZE by the amount of (number of extra segments * SHMADD) would take care of the problem. Eliminating extra segments is VERY important in the HPUX world. -- John Carlson Informix DBA WHSmith USA #include std_disclaimer.h /* These are my opinions, not my company's opinion */