Re: [GENERAL] Postgres performance and the Linux scheduler
Simon Windsor wrote: Can the performance of Postgres be boosted, especially on busy systems, using the none default DEADLINE Scheduler? I think that mostly depends on your storage. I personally have made one experience where (after weeks of trying everything else) I changed the scheduler from CFQ to deadline and immediately got about four times better performance. The storage in this case was a SAN. I don't have enough experience, but my guess is that the smarter your storage is, the less the kernel should try to optimize I/O. I assume that in my case the kernel's optimizations (which try to optimize things for a physical hard drive) and the SAN's optimizations got in each other's way. As I think is the case for all performance questions, there cannot be a certain answer -- the best thing is for you to try it out and see if it does something for you. Yours, Laurenz Albe -- Sent via pgsql-general mailing list (pgsql-general@postgresql.org) To make changes to your subscription: http://www.postgresql.org/mailpref/pgsql-general
Re: [GENERAL] Postgres performance and the Linux scheduler
On 16 June 2011 19:10, Simon Windsor simon.wind...@cornfield.me.uk wrote: Can the performance of Postgres be boosted, especially on busy systems, using the none default DEADLINE Scheduler? Probably, but it's a controversial area, and if you want to speed up a busy system, it would be almost the last thing to look at. Changing read-ahead settings would be almost the first thing to look at, as ways of improving the performance of Postgres by tweaking the operating system go. Increasing this parameter from the default is often very effective at speeding up sequential scans. -- Peter Geoghegan http://www.2ndQuadrant.com/ PostgreSQL Development, 24x7 Support, Training and Services -- Sent via pgsql-general mailing list (pgsql-general@postgresql.org) To make changes to your subscription: http://www.postgresql.org/mailpref/pgsql-general
Re: [GENERAL] Postgres performance and the Linux scheduler
On 06/16/2011 02:10 PM, Simon Windsor wrote: Can the performance of Postgres be boosted, especially on busy systems, using the none default DEADLINE Scheduler? Some system reports moderate improvements in throughput, and sometimes larger ones in worst-case latency, when switching from the default to the deadline scheduler. Others report best performance with the noop schedule. Changes here are not effective in a lot of cases though. I wrote an article for the first issue of PostgreSQL Magazine that mentions this, as the last of the most useful things you can tweak on Linux; that's available at http://pgmag.org/ -- Greg Smith 2ndQuadrant USg...@2ndquadrant.com Baltimore, MD PostgreSQL Training, Services, and 24x7 Support www.2ndQuadrant.us PostgreSQL 9.0 High Performance: http://www.2ndQuadrant.com/books
[GENERAL] Postgres performance and the Linux scheduler
Hi Can the performance of Postgres be boosted, especially on busy systems, using the none default DEADLINE Scheduler? Simon Simon Windsor Eml: mailto:simon.wind...@cornfield.org.uk simon.wind...@cornfield.org.uk Tel: 01454 617689 Mob: 07590 324560 There is nothing in the world that some man cannot make a little worse and sell a little cheaper, and he who considers price only is that man's lawful prey.
