Re: [PERFORM] bgwriter, checkpoints, curious (seeing delays)

2010-02-25 Thread Devrim GÜNDÜZ
On Thu, 2010-02-25 at 23:01 -0800, Tory M Blue wrote: > Checkpoint_timeout is the default and that looks like 5 mins (300 > seconds). And is obviously why I have such a discrepancy between time > reached and requested. If you have a high load, you may want to start tuning with 15 minutes, and bu

Re: [PERFORM] bgwriter, checkpoints, curious (seeing delays)

2010-02-25 Thread Tory M Blue
2010/2/25 Tory M Blue : > 2010/2/25 Devrim GÜNDÜZ : >> On Thu, 2010-02-25 at 22:12 -0800, Tory M Blue wrote: >>> shared_buffers = 1500MB >> >> Some people tend to increase this to 2.2GB(32-bit) or 4-6 GB (64 bit), >> if needed. Please note that more shared_buffers will lead to more >> pressure on b

Re: [PERFORM] bgwriter, checkpoints, curious (seeing delays)

2010-02-25 Thread Tory M Blue
2010/2/25 Devrim GÜNDÜZ : > On Thu, 2010-02-25 at 22:12 -0800, Tory M Blue wrote: >> shared_buffers = 1500MB > > Some people tend to increase this to 2.2GB(32-bit) or 4-6 GB (64 bit), > if needed. Please note that more shared_buffers will lead to more > pressure on bgwriter, but it also has lots of

Re: [PERFORM] bgwriter, checkpoints, curious (seeing delays)

2010-02-25 Thread Devrim GÜNDÜZ
On Thu, 2010-02-25 at 22:12 -0800, Tory M Blue wrote: > shared_buffers = 1500MB Some people tend to increase this to 2.2GB(32-bit) or 4-6 GB (64 bit), if needed. Please note that more shared_buffers will lead to more pressure on bgwriter, but it also has lots of benefits, too. > work_mem = 100MB

Re: [PERFORM] bgwriter, checkpoints, curious (seeing delays)

2010-02-25 Thread Jochen Erwied
Friday, February 26, 2010, 7:20:38 AM you wrote: > "checkpoint_completion_target (floating point) > interesting that it's a .5 second default setting and I'm seeing > exactly that .5 second delay. It's not an exact time, but a multiplier to 'checkpoint

Re: [PERFORM] bgwriter, checkpoints, curious (seeing delays)

2010-02-25 Thread Tory M Blue
On Thu, Feb 25, 2010 at 10:12 PM, Tory M Blue wrote: > Okay ladies and gents and the rest of you :) > > It's time I dig into another issue, and that's a curious 5 second > delay on connect, on occasion. Now, I believe the network to be sound > and there are zero errors on any servers, no retrans,

[PERFORM] bgwriter, checkpoints, curious (seeing delays)

2010-02-25 Thread Tory M Blue
Okay ladies and gents and the rest of you :) It's time I dig into another issue, and that's a curious 5 second delay on connect, on occasion. Now, I believe the network to be sound and there are zero errors on any servers, no retrans, no runts, nada nada nada. However I will continue to run tests

Re: [PERFORM] No hash join across partitioned tables?

2010-02-25 Thread Tom Lane
Bruce Momjian writes: > Did this get addressed? Partially. There are stats now but autovacuum is not bright about when to update them. regards, tom lane -- Sent via pgsql-performance mailing list (pgsql-performance@postgresql.org) To make changes to your subscription:

Re: [PERFORM] No hash join across partitioned tables?

2010-02-25 Thread Bruce Momjian
Did this get addressed? --- Tom Lane wrote: > Kris Jurka writes: > > The real problem is getting reasonable stats to pass through the partition > > Append step, so it can make a reasonable estimate of the join output size.

Re: [PERFORM] GiST index performance

2010-02-25 Thread Bruce Momjian
Was this corrected? I don't see any commits to seg.c. --- Matthew Wakeling wrote: > On Thu, 7 May 2009, Oleg Bartunov wrote: > > Did you try Guttman quadratic split algorithm ? We also found linear > > split algorithm for R

Re: [PERFORM] GiST index performance

2010-02-25 Thread Bruce Momjian
Was there every any conclusion on this issue? --- Matthew Wakeling wrote: > > Revisiting the thread a month back or so, I'm still investigating > performance problems with GiST indexes in Postgres. > > Looking at http://w

Re: [PERFORM] dbt2 performance

2010-02-25 Thread Yu-Ju Hong
Thanks for the reply. On Thu, Feb 25, 2010 at 5:48 PM, Greg Smith wrote: > Yu-Ju Hong wrote: > >> 2. Moreover, the disk utilization was high and the "await" time from >> iostat is around 500 ms. Could disk I/O limit the overall throughput? The >> server has 2 SATA disks, one for system and postg

Re: [PERFORM] dbt2 performance

2010-02-25 Thread Greg Smith
Yu-Ju Hong wrote: 2. Moreover, the disk utilization was high and the "await" time from iostat is around 500 ms. Could disk I/O limit the overall throughput? The server has 2 SATA disks, one for system and postgresql and the other is dedicated to logging (pg_xlog). As far as I understand, moder

[PERFORM] dbt2 performance

2010-02-25 Thread Yu-Ju Hong
Hi, I have a couple of questions about dbt2 performance. 1. I tested dbt2+postgresql 8.4.2 on my server, but the NOTPM is around only 320~390 with 10 connections and 30 warehouses. Increasing the number of connections did not improve the throughput? The NOPTM number does not seem very high to me.

Re: [PERFORM] Extracting superlatives - SQL design philosophy

2010-02-25 Thread Tom Lane
"Julien Theulier" writes: > Teradata provides a “qualify” syntax which works as a filtering condition on > a windowed function result. This is the only DB allowing this direct > filtering on windowed functions, from what I know. Seems like you could easily translate that into SQL-standard syntax

Re: [PERFORM] Extracting superlatives - SQL design philosophy

2010-02-25 Thread Julien Theulier
Hi all, Just for your information, and this is not related to PG directly: Teradata provides a “qualify” syntax which works as a filtering condition on a windowed function result. This is the only DB allowing this direct filtering on windowed functions, from what I know. So, as an example, th

Re: [PERFORM] Extracting superlatives - SQL design philosophy

2010-02-25 Thread Pierre C
-- More explicit select aggregate_using(max(date), city, temp, date) from bar group by city, temp order by city; select city, max(ROW(temp, date)) from bar group by city; Does not work (alas) for lack of a default comparison for record type. Another solution, which works wonders if you've go

Re: [PERFORM] Extracting superlatives - SQL design philosophy

2010-02-25 Thread Richard Huxton
On 24/02/10 23:37, Dave Crooke wrote: 1. The city temps table is a toy example, not meant to be realistic :-) You knew that and I guessed it, but it's worth stating these things for people who read the archives a year from now. 2. Yes, my (Java) algorithm is deterministic ... it will return