Hello,
I recently stumbled upon on what could be a planner bug or a corner case.
If " OR ..." is added to WHERE clause of SELECT query,
then the planner chooses a very inefficient plan. Consider a query:
SELECT count(k0.id)
FROM k0
WHERE 1 = 2
OR k0.id IN (
SELECT k1.k0_id
FRO
2008/1/30, Tom Lane <[EMAIL PROTECTED]>:
> "Dmitry Potapov" <[EMAIL PROTECTED]> writes:
> > 2008/1/25, Tom Lane <[EMAIL PROTECTED]>:
> >> It's hard to tell whether the planner is just being overoptimistic
> >> about the results of AND
Hello,
(Tom, sorry if you receive this letter twice. The first copy was
unintentionally sent with 'reply to sender only', I resend it to the
list, reply this one to keep the thread, please.)
2008/1/25, Tom Lane <[EMAIL PROTECTED]>:
> Well, there's our problem: an estimate of
I've got two huge tables with one-to-many relationship with complex
key. There's also a view, which JOINs the tables, and planner chooses
unoptimal plan on SELECTs from this view.
The db schema is declared as: (from on now, I skip the unsignificant
columns for the sake of simplicity)
CREATE TABL
2007/8/23, Greg Smith <[EMAIL PROTECTED]>:
>
> On Wed, 22 Aug 2007, Dmitry Potapov wrote:
>
> If you do end up following up with this via the Linux kernel mailing list,
> please pass that link along. I've been meaning to submit it to them and
> wait for the floo
2007/8/22, Kenneth Marshall <[EMAIL PROTECTED]>:
>
>
> You are working at the correct level. The bgwriter performs the I/O
> smoothing
> function at the database level. Obviously, the OS level smoothing function
> needed to be tuned and you have done that within the parameters of the OS.
> You may
2007/8/22, Joshua D. Drake <[EMAIL PROTECTED]>:
> > We've run into an issue of IO storms on checkpoints. Once in 20min
> > (which is checkpoint_interval) the database becomes unresponsive for
> about
> > 4-8 seconds. Query processing is suspended, server does nothing but
> writing
>
> What are
2007/8/22, Mark Mielke <[EMAIL PROTECTED]>:
>
> Are you able to show that the dirty pages are all coming from postgres?
>
>
I don't know how to prove that, but I suspect that nothing else except
postgres writes to disk on that system, because it runs nothing except
postgresql and syslog (which I c
Hello!
We run a large (~66Gb) web-backend database on Postgresql 8.2.4 on
Linux. The hardware is Dual Xeon 5130 with 16Gb ram, LSI Megaraid U320-2x
scsi controller w/512Mb writeback cache and a BBU. Storage setup contains 3
raid10 arrays (data, xlog, indexes, each on different arr
