Re: Oracle memory utilization on solaris

From: Tanel Põder <tanel.poder_at_abs.eee>
Date: Thu, 5 Aug 1999 16:13:35 +0300
Message-ID: <7obpon$bvn$1@news.estpak.ee>

> Another thing that I noticed is that the core Oracle processes,
> such as ora_smon_<SID> uses up about 300 Megs each. When a
> connection comes in a process is spawned that looks like
> "oracle<SID> (LOCAL=NO)". These connection processes also
> report using about 300 Megs each. Is that right? Why would
> connection processes need that much memmory? I imagine that
> it is because the process forked from another process and
> it inherited the memory mapped data files, but it just adds
> to the confusion of how much real memory is being used.

the answer for all this is - shared memory. if two processes have 1M mem both and 10M of shared memory, then they really take ~12M memory together, but top & other utilities count the shared mem in for both of the processes, and so you see that both processes have 11M of mem alloced.

because the oracleSID server processes access oracle shared memory (sga) you see that every little server process that actually has only 0.5-1M of mem,
is taking several hundreds of megs of your valuable mem.

try to decrease/increase the sga for some instance & you see that the server processe's alloced mem changes too.

afaik,
tanel. Received on Thu Aug 05 1999 - 08:13:35 CDT