Re: postgres sometimes returns no data

On 11/12/2015 12:07 PM, Venkata Balaji N wrote:
> Around that time I just see a bunch of "checkpoints are occurring too
> frequently...".  About a minute later and coincidentally around the
> time the
> pentaho job ends, I see "unexpected eof...could not receive data..target
> machine actively refused it.".  The reason this last item interests me is
> that this component is the last postgres item to run in the job. And the
> next/last component wouldn't run long when there is an empty file
> created by
> the problematic component.  The file is empty whenever this behavior
> occurs.


the too frequent checkpoint thing is purely a warning, that you probably
want to increase the checkpoint_segments count, I usually set it to 30
or 50 or something on a server that sees these warnings during heavy
activity.    I've never known it to cause data loss.

the unexpected EOF, that means the socket between the client and the
database server was closed unexpectedly, usually this means the client
application exited ungracefully.

HOWEVER, if this is a Linux server, I'd go looking in the system logs
for signs that the evil 'OOM Killer' has been active.   OOM Killer is an
abomination on a database server, it randomly kills processes that use
high memory, this can cause all sorts of problems.    If this is
happening, you should A) tune OOM Killer to be MUCH less active, and B)
reduce your postgresql memory usage to better suit your system environment.



--
john r pierce, recycling bits in santa cruz