Jeff wrote: > Dave Weaver wrote: > > For instance: > > SELECT station, air_temp FROM obs > > WHERE station = 'EGBB' > > AND valid_time > '28/8/03 00:00' > > AND valid_time < '28/10/03 00:00' > > > > takes 4 mins 32 secs. > > How many rows should that return? > [explain analyze will tell you that]
"explain analyze" doesn't seem to be part of this postgres version (or I misunderstood something). That particular query returned 24 rows. > and while that runs is your disk thrashing? vmstat's bi/bo columns will > tell you. The machine's over the other side of the building, so I can't physically see if the disk is thrashing. I'm not sure how to interpret the vmstat output; running "vmstat 1" shows me bi/bo both at zero (mostly) until I start the query. Then bi shoots up to around 2500 (bo remains around zero) until the query finishes. > 7.1 is quite old, but I do understand the pain of migraing to 7.3 [or > .4beta] with huge db's Is the upgrade likely to make a difference? I'm still none-the-wiser wether the problem I have is due to: 1 Postgres version 2 Database size 3 Table structure 4 Configuration issues 5 Slow hardware 6 All of the above 7 None of the above 8 Something else Thanks for the help, Dave. ---------------------------(end of broadcast)--------------------------- TIP 6: Have you searched our list archives? http://archives.postgresql.org