Re: [PERFORM] Question about caching on full table scans

2012-08-31 Thread Markus Innerebner
thanks a lot for your feedback. It helped me a lot and I have now a better overview in very specific hints, which I wasn't able to find in any documentation. Cheers Markus -- Sent via pgsql-performance mailing list (pgsql-performance@postgresql.org) To make changes to your subscription: http

Re: [PERFORM] Question about caching on full table scans

2012-08-30 Thread Scott Marlowe
On Thu, Aug 30, 2012 at 11:34 AM, Markus Innerebner wrote: > Hi Laurenz, > > > In your approach 1 to 3, what do you mean with "load into main memory"? > > > > I forgot to say: I use Java and connect with JDBC. > > in approach 1 I do an initial loading of the entire relation, by executing 1 > SQL q

Re: [PERFORM] Question about caching on full table scans

2012-08-30 Thread Jeff Janes
On Thu, Aug 30, 2012 at 10:34 AM, Markus Innerebner wrote: > > > To flush the filesystem cache (from Linux 2.6.16 on), use > > sync; echo 3 > /proc/sys/vm/drop_caches > > > I started to do that , and > yes, this solves my problem!! > > I assume that deleting file system cache implies that also pos

Re: [PERFORM] Question about caching on full table scans

2012-08-30 Thread Markus Innerebner
Hi Laurenz, > > In your approach 1 to 3, what do you mean with "load into main memory"? I forgot to say: I use Java and connect with JDBC. in approach 1 I do an initial loading of the entire relation, by executing 1 SQL query to load all edges in main memory, where I create my main memory st

Re: [PERFORM] Question about caching on full table scans

2012-08-30 Thread Albe Laurenz
Markus Innerebner wrote: > I am doing some runtime experiments in my implementation, which is computing multi-modal range queries > for a query point (if you want to know details check the website: www.isochrones.inf.unibz.it). > The network is explored using Dijkstra Shortest Path algorithm that s