Re: Database size Vs performance degradation

[Guillaume Lelarge <guillaume(at)lelarge(dot)info>]

Dave North a écrit :
> [...]
> > I'd suggest re-tuning as follows:
> >
> > 1) Increase shared_buffers to 10,000, test.  Things should be 
> > a bit faster.
> >
> > 2) Increase checkpoint_segments to 30, test.  What you want 
> > to watch for here whether there are periods where the server 
> > seems to freeze for a couple of seconds.  That's a 
> > "checkpoint spike".  If this happens, reduce 
> > checkpoint_segments to some sort of middle ground; some 
> > people never get above 10 before it's a problem.
> >
> > 3) Increase shared_buffers in larger chunks, as long as you 
> > don't see any problematic spikes you might usefully keep 
> > going until it's set to at least 100,000 before improvements 
> > level off.
>
> Do you happen to know if these are "reload" or "restart" tunable
> parameters?  I think I've read somewhere before that they are restart
> parameters (assuming I've set SHMMAX high enough of course)

shared_buffers and checkpoint_segments both need a restart.
> [...]
> I have to say, I've learnt a whole load from you folks here this
> morning...very enlightening.  I'm now moving on to your site Greg! :)

There's much to learn from Greg's site. I was kinda impressed by all the 
good articles in it.


--
Guillaume.
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