On 11/30/06, Jesse, Rich <Rich.Jesse@xxxxxx> wrote:
Jared, wouldn't your formula multiply shared memory (e.g. Oracle SGA size as reported by "ipcs -ma") by the number of Oracle processes (except for procs that don't connect to the instance, like the listener)? I think using ps output that way would be like saying that adding 25% of "X" and 25% of "Y" must equal 50% of "X+Y". While I've never taken the time (had the time?) to dealve into it, I think that pmap is accurate iff shared memory is accounted for. The trick is to determine if any other process is accessing that shared memory.
Which is another way of saying that pmap is not accurate. ;) My knee jerk is that this could be accomplished by making a "master" list of
shared memory (possibly using pmap outputs) to evaluate against whatever subset of processes you would want to see.
I do it with ipcs and /proc/*/maps This blog item mentions this problem, but doesn't really offer a solution:
I've probably already read that blog. Kinda wierd that no one's thought of a solution (even if it's only a 99%
one) to this, ain't it?
I have a solution (for linux) that comes fairly close. It involves a perl script to get a list of process ID's from ps, then calculates the memory usage from raw data in /proc/*/maps. There is also a small C program to get pagesize. -- Jared Still Certifiable Oracle DBA and Part Time Perl Evangelist