Very Computer

by **flavio.spi..** » Sat, 25 Dec 1999 04:00:00

Hi,
we are running AIX 4.3.2 and Sybase 11.9.2 and we have some
memory-related problem. After running fine a few days, the whole system
uses more memory, that means not a single process, "svmon -P" shows more
memory allocation for every process. If it were a single proc, I would
say, this proc does have a memory leak, but it's every process.
We do have a system (H70) with enough memory (2G) and a relatively tiny
database (6.6G). The system does operate nearly without paging (but if
paging space gets filled by, let's say, 5% of 2G, the db gets
incredibily slow).

Any ideas?

Best wishes and thanks

flavio

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by **David Owe** » Sat, 25 Dec 1999 04:00:00

flavio> Hi, we are running AIX 4.3.2 and Sybase 11.9.2 and we have
flavio> some memory-related problem. After running fine a few
flavio> days, the whole system uses more memory, that means not a
flavio> single process, "svmon -P" shows more memory allocation
flavio> for every process. If it were a single proc, I would say,
flavio> this proc does have a memory leak, but it's every process.

When you say *every process* could you define what you mean. If it is
all the Sybase processes, then this is probably what you would expect,
assuming that you are running a multi-engined system. Sybase creates
a shared memory segment that all of the engines attach to. If it is
every process on the system, I do not thing that Sybase can be blamed.
Not for *all* of them :-)

flavio> We do have a system (H70) with enough memory (2G) and a
flavio> relatively tiny database (6.6G). The system does operate
flavio> nearly without paging (but if paging space gets filled by,
flavio> let's say, 5% of 2G, the db gets incredibily slow).

How much memory is actually allocated to Sybase? What other apps, if
any, are running on the system.

dowen

by **Brian Blan** » Sun, 26 Dec 1999 04:00:00

Hi,

To find out how much memory Sybase is using, you can type
isql-1> sp_configure 'total memory'
isql-2> go

This will tell you how much memory is configured to the Sybase server. This
is in 2K pages, so a number of 300,000 really means 600MB. This is also
total memory. The sybase system first takes what it needs for connections,
and general system stuff, and the rest is used for cache. Also, this is
shared memory, so all engines, no matter how many engines you start, will
use this 600MB (or how much ever you setup). I doubt that there is a memory
leak from Sybase as Sybase memory is only allocated at startup time. Also,
Sybase expects at startup that there is 600MB of free physical memory
available (not swap). That means, if you have 500MB of Ram and 2GB of swap
space, this 600MB database will not start and will actually give you an
error upon initialization saying that there is not enouph memory available
even though there is plenty. I'm currently using Sybase on Sun, not AIX,
but I'm sure it's very similar.

I used the AIX platform about three years ago last. At the time, they had
some problems with zombie processes. We had to reboot daily to get our
memory back. Maybe you should speak with IBM and find out where all your
memory is being used.

- Brian Blank

> Hi,
> we are running AIX 4.3.2 and Sybase 11.9.2 and we have some
> memory-related problem. After running fine a few days, the whole system
> uses more memory, that means not a single process, "svmon -P" shows more
> memory allocation for every process. If it were a single proc, I would
> say, this proc does have a memory leak, but it's every process.
> We do have a system (H70) with enough memory (2G) and a relatively tiny
> database (6.6G). The system does operate nearly without paging (but if
> paging space gets filled by, let's say, 5% of 2G, the db gets
> incredibily slow).

> Any ideas?

> Best wishes and thanks

> flavio

> Sent via Deja.com http://www.deja.com/
> Before you buy.

by **arun.ka..** » Tue, 28 Dec 1999 04:00:00

> we are running AIX 4.3.2 and Sybase 11.9.2 and we have some
> memory-related problem. After running fine a few days, the whole
> system uses more memory, that means not a single process, "svmon -P"
> shows more memory allocation for every process.

I understand you are talking about OS processes and not ASE threads.
Have you applied proper OS patches? Contact your AIX tech support if all
OS processes over period of time try to grab more memory.

Quote:> If it were a single proc, I would say, this proc does have a memory
> leak, but it's every process. We do have a system (H70) with enough
> memory (2G) and a relatively tiny database (6.6G). The system does
> operate nearly without paging (but if paging space gets filled by,
> let's say, 5% of 2G, the db gets incredibily slow).

The AIX server may need some tuning, additionally you may go through ASE
installtion guides to start up 10 async io daemons, understand issues
with AIX raw disk ios etc.

arun

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by **epi..** » Tue, 28 Dec 1999 04:00:00

> > we are running AIX 4.3.2 and Sybase 11.9.2 and we have some
> > memory-related problem. After running fine a few days, the whole
> > system uses more memory, that means not a single process, "svmon -P"
> > shows more memory allocation for every process.

> I understand you are talking about OS processes and not ASE threads.
> Have you applied proper OS patches? Contact your AIX tech support if
all
> OS processes over period of time try to grab more memory.

Yes, it's the central working segment that allocs more and more memory.
We have applied the latest kernel-patches for 4.3.2, that seemed to
solve the worst things, but the problems remains. I just thought, that
someone had similar problems with aix (I think that's not a
sybase-problem, but one never knows).

Quote:
> > If it were a single proc, I would say, this proc does have a memory
> > leak, but it's every process. We do have a system (H70) with enough
> > memory (2G) and a relatively tiny database (6.6G). The system does
> > operate nearly without paging (but if paging space gets filled by,
> > let's say, 5% of 2G, the db gets incredibily slow).

> The AIX server may need some tuning, additionally you may go through
ASE
> installtion guides to start up 10 async io daemons, understand issues
> with AIX raw disk ios etc.

Yes, we all covered that. I think we have the proper number of
aio-daemons and the proper number of engines. We had ibm tech support
here and the technician didn't find any misconfiguration either (he, at
least, crashed our system ;-)).

thank you and best wishes

flavio

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Before you buy.

by **flavio.spi..** » Wed, 29 Dec 1999 04:00:00

> flavio> Hi, we are running AIX 4.3.2 and Sybase 11.9.2 and we have
> flavio> some memory-related problem. After running fine a few
> flavio> days, the whole system uses more memory, that means not a
> flavio> single process, "svmon -P" shows more memory allocation
> flavio> for every process. If it were a single proc, I would say,
> flavio> this proc does have a memory leak, but it's every process.

> When you say *every process* could you define what you mean. If it is
> all the Sybase processes, then this is probably what you would expect,
> assuming that you are running a multi-engined system. Sybase creates
> a shared memory segment that all of the engines attach to. If it is
> every process on the system, I do not thing that Sybase can be blamed.
> Not for *all* of them :-)

All the procs are growing and I do think, that Sybase can't be blamed.
It's some sort of shared segment that grows. I also found some
usenet-postings with a very similar problem with aix and a webserver and
aix and oracle. Perhaps I have to tune vmm, but I don't know how yet.

Quote:
> flavio> We do have a system (H70) with enough memory (2G) and a
> flavio> relatively tiny database (6.6G). The system does operate
> flavio> nearly without paging (but if paging space gets filled by,
> flavio> let's say, 5% of 2G, the db gets incredibily slow).

> How much memory is actually allocated to Sybase? What other apps, if
> any, are running on the system.

We have 300'000 Pages for Sybase and a reporting tool based on X11.

Best wishes

Flavio

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by **Anthony Mandi** » Thu, 30 Dec 1999 04:00:00

> All the procs are growing and I do think, that Sybase can't be blamed.
> It's some sort of shared segment that grows. I also found some
> usenet-postings with a very similar problem with aix and a webserver and
> aix and oracle. Perhaps I have to tune vmm, but I don't know how yet.

If all processes grow in memory size then its definitely an OS
related issue. Since its all processes, it may be a memory related
bug in one of the shared libraries (most likely a common one to
all like libc). Since its an AIX issue, check around for system
patches related to shared libraries and the kernel for your
particular version.

-am

by **kinki** » Fri, 31 Dec 1999 04:00:00

> flavio> Hi, we are running AIX 4.3.2 and Sybase 11.9.2 and we have
> flavio> some memory-related problem. After running fine a few
> flavio> days, the whole system uses more memory, that means not a
> flavio> single process, "svmon -P" shows more memory allocation
> flavio> for every process. If it were a single proc, I would say,
> flavio> this proc does have a memory leak, but it's every process.

> When you say *every process* could you define what you mean. If it is
> all the Sybase processes, then this is probably what you would expect,
> assuming that you are running a multi-engined system. Sybase creates
> a shared memory segment that all of the engines attach to. If it is
> every process on the system, I do not thing that Sybase can be blamed.
> Not for *all* of them :-)

Also, if I recall correctly, AIX's malloc() implementation does not return
free()d memory back to the system (I'm not entirely sure about this, I
might be wrong), but keeps it in a per-process free space, to be used for
subsequent requests to malloc(). Thus process sizes can only grow as heap
fragmentation (same stuff as the more-known disk fragmentation) happens.

--
/Kinkie

Se sulla scatola c'e` scritto "Per windows 95 e superiori", dovrebbe
funzionare sotto Linux, vero?

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