On Wed, Aug 5, 2009 at 6:20 AM, Matthew Wakeling<matthew@flymine.org> wrote:
> It is certainly doing a sequential scan. So are you saying that it will
> start a sequential scan from a different part of the table each time, even
> in the absence of other simultaneous sequential scans? Looks like I'm going
> to have to remove the limit to get sensible results - I only added that to
> make the query return in a sensible time for performance testing.
>
> Some trivial testing with "select * from location limit 10;" indicates that
> it starts the sequential scan in the same place each time - but is this
> different from the above query?
Maybe it's because of this?
http://www.postgresql.org/docs/8.3/static/runtime-config-compatible.html#GUC-SYNCHRONIZE-SEQSCANS
...Robert