topic Re: Memory Allocation Error in Operating System - Tru64 Unix

Memory Allocation Error

abhay kumar_2 — Thu, 20 Nov 2003 12:05:29 GMT

We are running Sybase 11.9.3 on Digital Unix 4.0F.

We havea program failing continuously with "memory allocation error". When the program was running, the free memory falls gradually from 2 Gb to almost zero, and then the program fails.

The ulimit -a show the limit of data segment set to 2 Gb.

We can try increasing the limit, but it requires a reboot of production server and there is no guarantee that it will fix the problem.

Help urgently needed !!

abhay

Re: Memory Allocation Error

Michael Schulte zur Sur — Thu, 20 Nov 2003 12:19:38 GMT

Hi abhay,

I would assume, that this programme is allocating memory without releasing it. What programme is it?

greetings,

Michael

Re: Memory Allocation Error

Ilkka Seittenranta — Fri, 21 Nov 2003 03:27:04 GMT

You wrote "..free memory falls ... almost zero,"

How much you have a memory?

If the data segment size is almost same you get the trouble. You database software needs to use lot of physical memory but there must be also enough free physical memory to run OS, applications and small part of all users program.

Ilkka S

Re: Memory Allocation Error

Ralf Puchner — Fri, 21 Nov 2003 03:32:57 GMT

"memory allocation error" is mostly a problem of stack and data-size but depend also on the used functions/routines.

Databases normally allocates all statically memory using their own memory management. So the first thing to check is if the software vendor offers a tuning guide and to check the named parameters within this guides.

Maybe changing the swap-mode to lazy swap (removing /sbin/swapdefault and reboot) will also solve this problem - but this will be mentioned within the tuning guide.