On Sun, Feb 26, 2012 at 12:37 PM, Stefan Keller <sfkeller@xxxxxxxxx> wrote: > 2012/2/26 Andy Colson <andy@xxxxxxxxxxxxxxx> wrote: >>>> How about after you load the data, vacuum freeze it, then do something >>>> like: >>>> >>>> SELECT count(*) FROM osm_point WHERE tags @> 'tourism=>junk' >>>> >>>> -Andy >>> >>> >>> That good idea is what I proposed elsewhere on one of the PG lists and >>> got told that this does'nt help. >>> > ... >> I don't buy that. Did you test it? Who/where did you hear this? And... >> how long does it take after you replace the entire table until things are >> good and cached? One or two queries? >> >> After a complete reload of the data, do you vacuum freeze it? > > Yes. > >> After a complete reload of the data, how long until its fast? > > Just after the second query. You can try it yourself online here: > http://bit.ly/A8duyB The second instance of the exact same query is fast. How long until all similar but not identical queries are fast? Cheers, Jeff -- Sent via pgsql-performance mailing list (pgsql-performance@xxxxxxxxxxxxxx) To make changes to your subscription: http://www.postgresql.org/mailpref/pgsql-performance
