2009/3/21 M. Edward (Ed) Borasky zzn...@gmail.com:
I just discovered this on a LinkedIn user group:
http://bugzilla.kernel.org/show_bug.cgi?id=12309
Is anyone here seeing evidence of this in PostgreSQL??
I've been hit by an I/O wait problem, as described here:
On Sun, Mar 22, 2009 at 8:49 AM, Laurent Wandrebeck
l.wandreb...@gmail.com wrote:
2009/3/21 M. Edward (Ed) Borasky zzn...@gmail.com:
I just discovered this on a LinkedIn user group:
http://bugzilla.kernel.org/show_bug.cgi?id=12309
Is anyone here seeing evidence of this in PostgreSQL??
I've
On Fri, 20 Mar 2009, M. Edward (Ed) Borasky wrote:
I just discovered this on a LinkedIn user group:
http://bugzilla.kernel.org/show_bug.cgi?id=12309
I would bet there's at least 3 different bugs in that one. That bug
report got a lot of press via Slashdot a few months ago, and it's picked
2009/3/22 Greg Smith gsm...@gregsmith.com:
On Fri, 20 Mar 2009, M. Edward (Ed) Borasky wrote:
I just discovered this on a LinkedIn user group:
http://bugzilla.kernel.org/show_bug.cgi?id=12309
I would bet there's at least 3 different bugs in that one. That bug report
got a lot of press via
So the bottom line here is just that the estimated n_distinct is too
low. We've seen before that the equation we use tends to do that more
often than not. I doubt that consistently erring on the high side would
be better though :-(. Estimating n_distinct from a limited sample of
the
I hit an interestinhg paper on n_distinct calculation:
http://www.pittsburgh.intel-research.net/people/gibbons/papers/distinct-values-chapter.pdf
the PCSA algorithm described there requires O(1) calculation per
value. Page 22 describes what to do with updates streams.
This I think
marcin mank marcin.m...@gmail.com writes:
I hit an interestinhg paper on n_distinct calculation:
http://www.pittsburgh.intel-research.net/people/gibbons/papers/distinct-values-chapter.pdf
I don't think we're quite ready to make ANALYZE read every row of a
table in order to estimate n_distinct.
On Mon, 23 Mar 2009, Laurent Wandrebeck wrote:
I thought about completely fair scheduler at first, but that one came
in around 2.6.21.
CFS showed up in 2.6.23.
I think that forcing the system to write down more often, and smaller
data just hides the problem, and doesn't correct it.
That's
