Could be also Linux related. Phoronix has been talking about regression due to some modification in ext4. It could be due to this too.
Emilie Laffray On 6 May 2010 23:14, "Frederik Ramm" <frede...@remote.org> wrote: Hi, I had posted about performance problems with Postgres 8.4 in September last year already. With Ubuntu Lucid just released, which comes with 8.4 by default, I played around some more. Unfortunately I am still a little bit away from having systematic, comparable results, but I have the impression that importing updates with osm2pgsql is somehow buggy (performance-wise) in 8.4. I'm running this on a machine with SSD. With 8.3, the process was disk-bound despite SSD, which is what I would expect, after all there's not much to compute. With 8.4, a (large, ~ 1 day) test diff takes about four times as long to load. This is unacceptable and I will probably have go back to 8.3 because of that until I can find out exactly what the problem is. When searching for possible reasons on the web, I found this message about Postgres 9.0 and irregularities with intarray index usage: http://osdir.com/ml/pgsql-hackers/2010-03/msg01035.html It could have *something* to do with what I am seeing, however I could not reproduce intarray operations being slower from within a function than from the command line. I'll investigate this further and report back with anything I find; for the time being just be warned that there are isolated indications of Postgres 8.4 being less suitable for OSM than 8.3. (I am largely ignorant of any changes between 8.3 and 8.4, and simply set my config options to the same I had been using with 8.3; it is possible that 8.4 requires something to be configured differently to work.) I'd also be interested to hear from anyone who, despite this message, plays with 8.4 (or even 9.0 alpha) and has something to say. Bye Frederik -- Frederik Ramm ## eMail frede...@remote.org ## N49°00'09" E008°23'33" _______________________________________________ dev mailing list dev@openstreetmap.org http://lists.openstreetmap.org/listinfo/dev
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