On 10/1/06, Fred Tyler <fredty8@gmail.com> wrote:
> > However, my machine looses between 500 M and 800 M in two weeks, and
> > within that time, I restart pg only very few times, say 3-4 times.
> > Does pg allocate other shmem blocks? If there is really a kernel memory
> > problem in shmem, how can I loose so much memory?
>
> This is the same thing I am seeing -- 500-1GB memory lost every two
> weeks -- and I don't restart pg at all. So, whatever is causing this
> is not due to pg restarts. I am running the same software as everyone
> else who has had this problem though: Apache, Postgres, and mod_perl
> on Linux (I know there's the guy seeing it on BSD also).
For the record, after upgrading the leaky machine from postgres 7.4.9
to 7.4.13, the memory leak is still very much present. (My original
configuration details are quoted below.)
From a fresh reboot of the server, with no postgres restarts, crashes,
or anything abnormal, I'm seeing a memory loss of around 50-100MB per
day.
As things now stand, I have two machines with the exact same software
configuration, but one machine (the leaky one) is running kernel
2.6.12.6, and the other machine (non-leaky one) is running 2.6.16.27.
The hardware is slightly different (both servers are Intel, but one is
dual core), and the non-leaky machine has about 1/2 the load of the
leaky machine, but all evidence right now is pointing to a kernel leak
that was fixed somewhere between 2.6.12.6 and 2.6.16.12.
> As I mentioned on the mod_perl list, I'm seeing the loss on a machine
> with ~350 vhosted domains all running a mod_perl CMS:
>
> Apache 1.3.37
> Postgres 7.4.9
> Linux 2.6.12.6
> mod_perl 1.29
>
> However, I am not seeing any loss at all on another machine with ~100
> vhosted domains running the same CMS, but with the following software:
>
> Apache 1.3.37
> Postgres 7.4.13
> Linux 2.6.16.27
> mod_perl 1.29
>
> I cannot be certain that it's not just due to the ligher load (100 vs
> 350 vhosts), but I have not seen a single MB of lost memory on the
> second machine, and am inclined to believe that the problem is fixed
> with that setup (aside from the kernel and postgres, the two machines
> are running the same software).
>
> Tonight I am going to upgrade postgres on the first machine and see if
> it makes any difference, but it'll be about a week before I know for
> sure if memory is still being lost (it's such a slow leak that you
> cannot tell with just a couple days).
>