Thanks to everyone who responded to my question about outer joins.
Now I have some more .
I'm trying to learn what explain can tell me & whether there are any
reasonable ways to push it's choices in one direction based on my knowledge
of the tables without really screwing up general performance.
Tom Lane wrote:
> Raphael Bauduin <[EMAIL PROTECTED]> writes:
> > At some times, it seems to hang: it doesn't insert any rows for more
> > than 10 seconds. At that time, the postmaster process takes 0%. Why is
> > that?
>
> At a guess, you're seeing the syncer daemon flushing a lot of dirty
> ker
Naomi Walker wrote:
> From my many years of Informix knowledge, we noticed that checkpoints,
> during high activity times, did take a long time, because it locked the
> shared memory segment. We found that setting the checkpoint knobs to flush
> almost constantly, overall, was much better for
From my many years of Informix knowledge, we noticed that checkpoints,
during high activity times, did take a long time, because it locked the
shared memory segment. We found that setting the checkpoint knobs to flush
almost constantly, overall, was much better for performance.
Looking in po
Raphael Bauduin <[EMAIL PROTECTED]> writes:
> At some times, it seems to hang: it doesn't insert any rows for more
> than 10 seconds. At that time, the postmaster process takes 0%. Why is
> that?
At a guess, you're seeing the syncer daemon flushing a lot of dirty
kernel disk buffers out to disk,
Jean-Christophe ARNU (JX) <[EMAIL PROTECTED]> writes:
> When I use timestamps + interval in where clauses, query performance is
> slowed down by a factor of 20 or 30 For exemple :
> select timestamp,value
> from measure
> where timestamp(now() - '1 hour'::interval)
>
On Wed, 2002-04-10 at 14:00, Raphael Bauduin wrote:
...
> dpkg -l postgresql
> Desired=Unknown/Install/Remove/Purge/Hold
> | Status=Not/Installed/Config-files/Unpacked/Failed-config/Half-installed
> |/ Err?=(none)/Hold/Reinst-required/X=both-problems (Status,Err: uppercase=bad)
> ||/ Name
On 10 Apr 2002 at 10:55, Dan Langille wrote:
> If there is an index on that field, casting to a timestamp may help the
> optimization. Therefore I suggested that it be tried.
And using "explain" will show the plan for that command. I recommend
using that too.
--
Dan Langille
The FreeBSD Dia
On 10 Apr 2002 at 10:44, JX wrote:
> Le Wed, 10 Apr 2002 09:27:09 -0400
> "Dan Langille" <[EMAIL PROTECTED]> me disait que :
>
> > On 10 Apr 2002 at 9:13, JX wrote:
> >
> > > Le Wed, 10 Apr 2002 09:06:55 -0400
> > > "Dan Langille" <[EMAIL PROTECTED]> me disait que :
> > >
> > > > On 10 Apr 200
Le Wed, 10 Apr 2002 09:27:09 -0400
"Dan Langille" <[EMAIL PROTECTED]> me disait que :
> On 10 Apr 2002 at 9:13, JX wrote:
>
> > Le Wed, 10 Apr 2002 09:06:55 -0400
> > "Dan Langille" <[EMAIL PROTECTED]> me disait que :
> >
> > > On 10 Apr 2002 at 11:51, Gaetano Mendola wrote:
> > >
> > > > "Jea
On 10 Apr 2002 at 11:51, Gaetano Mendola wrote:
> "Jean-Christophe ARNU (JX)" <[EMAIL PROTECTED]> wrote:
> > Hello all.
> > I've a performance problem on specific requests :
> >
> > When I use timestamps + interval in where clauses, query performance is
> > slowed down by a factor of 20 or 3
Hi,
having read on this list (some time ago) that inserts could become slow
when there are foreign keys constraints, I wanted to test it. So I
created a DB with 5 tables (T1 -> T5) with, for 0
"Jean-Christophe ARNU (JX)" <[EMAIL PROTECTED]> wrote:
> Hello all.
> I've a performance problem on specific requests :
>
> When I use timestamps + interval in where clauses, query performance is
> slowed down by a factor of 20 or 30 For exemple :
> select timestamp,value
> from measu
Hello all.
I've a performance problem on specific requests :
When I use timestamps + interval in where clauses, query performance is
slowed down by a factor of 20 or 30 For exemple :
select timestamp,value
from measure
where timestamp(now() - '1 hour'::interval
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