Re: [GENERAL] pg_dump slow on windows

2012-09-22 Thread Jasen Betts
On 2012-09-06, Kobus Wolvaardt kobusw...@gmail.com wrote:

 Something that is curios is that if a DB takes long, it really takes
 horribly long like some kind of a lock is holding it. It would sit at a few
 kb dump size for 20 minutes en then run a bit and get stuck again (as far
 as we can tell), what we do know is that it is way to slow for some IO or
 cpu starvation. We have seen a 5GB backup sitting at 1Gb after 12hours and
 then we stop it.

 Any siggestions? Can autovacume or lack thereof cause this? It seems noone
 has been doing any maintenance on the DB (it does look like autovacuum is
 running), so any suggestions would be nice.

perhaps some sort of DML could cause this, I've seen DML hang during
dumps 

turn on logging of slow queries and check the logs after the next
speed disaster.

-- 
⚂⚃ 100% natural



-- 
Sent via pgsql-general mailing list (pgsql-general@postgresql.org)
To make changes to your subscription:
http://www.postgresql.org/mailpref/pgsql-general


[GENERAL] pg_dump slow on windows

2012-09-06 Thread Kobus Wolvaardt
Hi,

I hope this is the right list. I have read through a few pg_dump slow posts
but none of them seem to apply to our case. We have a nice big server
running windows server 2008 and postgres 8.4. The machine does nothing else
and every so often running the nightly backup take 10 to 12 hours to
complete. Most nights it completes in 1 to 2 hours. Just for some context,
5 rather large DBs get backed up. All of them have many schema (100s) and
many many tables.


A few things I cannot change. I cannot switch to Linux even though I want
to. I cannot upgrade to a newer postgres just yet (though 9.0 should be
installed before year end). One of the issues holding a newer postgres up
is the fact that backups aren't running right. :-)

So my first thought was the machine or DB being over worked, but apart from
a lone vacuum at 2am there is little else going on, the cpu seems fine. I
thought maybe IO, but running the command as a user during peak working
hours seems to run well ( hour per DB).

Something that is curios is that if a DB takes long, it really takes
horribly long like some kind of a lock is holding it. It would sit at a few
kb dump size for 20 minutes en then run a bit and get stuck again (as far
as we can tell), what we do know is that it is way to slow for some IO or
cpu starvation. We have seen a 5GB backup sitting at 1Gb after 12hours and
then we stop it.

Any siggestions? Can autovacume or lack thereof cause this? It seems noone
has been doing any maintenance on the DB (it does look like autovacuum is
running), so any suggestions would be nice.

Thanks,
Kobus

P.S. Would we see performance improvements on windows going from 8.4 to
9.0? Any comment on the difference between 32 and 64? Is it a safe
migration?


Re: [GENERAL] pg_dump slow on windows

2012-09-06 Thread John R Pierce

On 09/06/12 1:34 PM, Kobus Wolvaardt wrote:


Something that is curios is that if a DB takes long, it really takes 
horribly long like some kind of a lock is holding it. It would sit at 
a few kb dump size for 20 minutes en then run a bit and get stuck 
again (as far as we can tell), what we do know is that it is way to 
slow for some IO or cpu starvation. We have seen a 5GB backup sitting 
at 1Gb after 12hours and then we stop it.


Any siggestions? Can autovacume or lack thereof cause this? It seems 
noone has been doing any maintenance on the DB (it does look like 
autovacuum is running), so any suggestions would be nice. 

try...

select * from pg_stat_activity;
select * from pg_locks;

next time its hung



--
john r pierceN 37, W 122
santa cruz ca mid-left coast



--
Sent via pgsql-general mailing list (pgsql-general@postgresql.org)
To make changes to your subscription:
http://www.postgresql.org/mailpref/pgsql-general