Re: [PERFORM] DRBD and Postgres: how to improve the perfomance?

Hi, Decibel! wrote: Actually, in this case, I suspect that latency will be far more critical than overall bandwidth. I don't know if it's inherent to Gig-E, but my limited experience has been that Gig-E has higher latency than 100mb. I've been looking for some benchmarks, but it's rather hard

Re: [PERFORM] Replication

Hi, Andrew Sullivan wrote: This isn't quite true. Slony-II was originally conceived by Jan as an attempt to implement some of the Postgres-R ideas. Oh, right, thanks for that correction. Part of the problem, as near as I could tell, was that we had no group communication protocol that would

Re: [PERFORM] Replication

Hi, Craig James wrote: Is Postgres-R the same thing as Slony-II? There's a lot of info and news around about Slony-II, but your web page doesn't seem to mention it. Hm... true. Good point. Maybe I should add a FAQ: Postgres-R has been the name of the research project by Bettina Kemme et al.

Re: [PERFORM] Replication

Hi, Joshua D. Drake wrote: Slony-II Seems brilliant, a solid theoretical foundation, at the forefront of computer science. But can't find project status -- when will it be available? Is it a pipe dream, or a nearly-ready reality? Dead Not quite... there's still Postgres-R, see www.postgre

Re: [PERFORM] dbt2 NOTPM numbers

Hi, Mark Wong wrote: Yeah, I ran with 500+ warehouses, but I had 6 14-disk arrays of 15K RPM scsi drives and 6 dual-channel controllers... :) Lucky you! In the mean time, I've figured out that the box in question peaked at about 1450 NOTPMs with 120 warehouses with RAID 1+0. I'll try to comp

Re: [PERFORM] dbt2 NOTPM numbers

Heikki Linnakangas wrote: Markus Schiltknecht wrote: For dbt2, I've used 500 warehouses and 90 concurrent connections, default values for everything else. 500? That's just too much for the hardware. Start from say 70 warehouses and up it from there 10 at a time until you hit the

Re: [PERFORM] dbt2 NOTPM numbers

Hi, Jim Nasby wrote: I don't think that kind of testing is useful for good raid controllers on RAID5/6, because the controller will just be streaming the data out; it'll compute the parity blocks on the fly and just stream data to the drives as fast as possible. That's why I called it 'simpl

Re: [PERFORM] dbt2 NOTPM numbers

Hi, Heikki Linnakangas wrote: Maybe, TPC-C is very write-intensive. I don't know much about RAID stuff, but I think you'd really benefit from a separate WAL drive. You could try turning fsync=off to see if that makes a difference. Hm.. good idea, I'll try that. Oh, and how many connections a

Re: [PERFORM] dbt2 NOTPM numbers

Hi, Heikki Linnakangas wrote: I still suspect there's something wrong with plans, I doubt you can get that bad performance unless it's doing something really stupid. Agreed, but I'm still looking for that really stupid thing... AFAICT, there are really no seqscans..., see the pg_stat_user_ta

Re: [PERFORM] dbt2 NOTPM numbers

Hi, PFC wrote: You have a huge amount of iowait ! Yup. Did you put the xlog on a separate disk ? No, it's all one big RAID6 for the sake of simplicity (plus I doubt somewhat, that 2 disks for WAL + 5 for data + 1 spare would be much faster than 7 disks for WAL and data + 1 spare

Re: [PERFORM] dbt2 NOTPM numbers

Hi, Heikki Linnakangas wrote: There's clearly something wrong. The response times are ridiculously high, they should be < 5 seconds (except for stock level transaction) to pass a TPC-C test. I wonder if you built any indexes at all? Hm.. according to the output/5/db/plan0.out, all queries use

[PERFORM] dbt2 NOTPM numbers

Hi, I'm currently playing with dbt2 and am wondering, if the results I'm getting are reasonable. I'm testing a 2x Dual Core Xeon system with 4 GB of RAM and 8 SATA HDDs attached via Areca RAID Controller w/ battery backed write cache. Seven of the eight platters are configured as one RAID6, o

Re: [PERFORM] File Systems Compared

Hi, Steinar H. Gunderson wrote: This is a rather long sentence without any kind of word wrapping except what would be imposed on your own side -- how to set that up properly depends on the sending e-mail client, but in mine it's just a matter of turning off the word wrapping in your editor :-

Re: [PERFORM] File Systems Compared

Hi, Alexander Staubo wrote: Care to post these numbers *without* word wrapping? Thanks. How is one supposed to do that? Care giving an example? Markus ---(end of broadcast)--- TIP 2: Don't 'kill -9' the postmaster

Re: [GENERAL] [PERFORM] Locking in PostgreSQL?

Hi, Dave Cramer wrote: Apparently I've completely misunderstood MVCC then Probably not. You are both somewhat right. Jens Schipkowski wrote: >> Thats not right. UPDATE will force a RowExclusiveLock to rows >> matching the WHERE clause, or all if no one is specified. That almost right, Ro