On Wed, 2007-09-19 at 10:38 -0700, brauagustin-susc@xxxxxxxxxxxx wrote: > Hi all. > Recently I have installed a brand new server with a Pentium IV 3.2 > GHz, SATA Disk, 2GB of Ram in Debian 4.0r1 with PostgreSQL 8.2.4 > (previously a 8.1.9). > I have other similar server with an IDE disk, Red Hat EL 4 and > PostgreSQL 8.2.3 > > I have almost the same postgresql.conf in both servers, but in the new > one (I have more work_mem than the other one) things go really slow. > I began to monitor i/o disk and it's really ok, I have test disk with > hdparm and it's 5 times faster than the IDE one. > Running the same queries in both servers in the new one it envolves > almost 4 minutes instead of 18 seconds in the old one. > Both databases are the same, I have vacuum them and I don't know how > to manage this issue. > The only weird thing is than in the older server running the query it > uses 30% of CPU instead of 3 o 5 % of the new one!!! > What's is happening with this server? I upgrade from 8.1.9 to 8.2.4 > trying to solve this issue but I can't find a solution. > > Any ideas? It could be a planning issue. Have you analyzed the new database to gather up-to-date statistics? A comparison of EXPLAIN ANALYZE results for an example query in both systems should answer that one. Another possibility because you're dealing with lower-end drives is that you have a case of one drive lying about fsync where the other is not. If possible, try running your test with fsync=off on both servers. If there's a marked improvement on the new server but no significant change on the old server then you've found your culprit. -- Mark Lewis ---------------------------(end of broadcast)--------------------------- TIP 2: Don't 'kill -9' the postmaster
