Re: Memory issues

Hi
Thanks for your answer.
I understood that the server is ok memory wise.
What can I check on the client side or the DB queries?

Thank u.
On Wed, Sep 26, 2012 at 2:56 AM, Scott Marlowe <scott(dot)marlowe(at)gmail(dot)com>wrote:

> On Mon, Sep 24, 2012 at 12:45 AM, Shiran Kleiderman <shirank1(at)gmail(dot)com>
> wrote:
> >
> >
> > Hi,
> > I'm using and Amazon ec2 instance with the following spec and the
> > application that I'm running uses a postgres DB 9.1.
> > The app has 3 main cron jobs.
> >
> > Ubuntu 12, High-Memory Extra Large Instance
> > 17.1 GB of memory
> > 6.5 EC2 Compute Units (2 virtual cores with 3.25 EC2 Compute Units each)
> > 420 GB of instance storage
> > 64-bit platform
> >
> > I've changed the main default values under file postgresql.conf to:
> > shared_buffers = 4GB
> > work_mem = 16MB
> > wal_buffers = 16MB
> > checkpoint_segments = 32
> > effective_cache_size = 8GB
> >
> > When I run the app, after an hour or two, free -m looks like below ans
> the
> > crons can't run due to memory loss or similar (i'm new to postgres and db
> > admin).
> > Thanks!
> >
> > free -m, errors:
> >
> > total used free shared buffers cached
> > Mem: 17079 13742 3337 0 64 11882
> > -/+ buffers/cache: 1796 15283
> > Swap: 511 0 511
>
> You have 11.8G cached, that's basically free memory on demand.
>
> > total used free shared buffers cached
> > Mem: 17079 16833 245 0 42 14583
> > -/+ buffers/cache: 2207 14871
> > Swap: 511 0 511
>
> Here you have 14.5G cached, again that's free memory so to speak.
> I.e. when something needs it it gets allocated.
>
> > **free above stays low even when nothing is running.
> >
> >
> > **errors:
> > DBI connect('database=---;host=localhost','postgres',...) failed: could
> not
> > fork new process for connection: Cannot allocate memory
> > could not fork new process for connection: Cannot allocate memory
>
> This error is happening in your client process. Maybe it's 32 bit or
> something and running out of local memory in its process space? Maybe
> memory is so fragmented that no large blocks can get allocated or
> something? Either way, your machine has plenty of memory according to
> free. BTW, it's pretty common for folks new to unix to mis-read free
> and not realize that cached memory + free memory is what's really
> available.
>

--
Best,
Shiran Kleiderman
+972 - 542380838
Skype - shirank1