On Mar 6, 2007, at 11:40 AM, Tom Lane wrote:
the *actual* average number of rows scanned is 3773. I'm not sure why
this should be --- is it possible that the distribution of keys in
symptom_reports is wildly uneven? This could happen if all of the
physically earlier rows in symptom_reports contain the same small set
of symptom_ids, but the stats don't seem to indicate such a skew.
Hi Tom, you are correct, the distribution is uneven... In the 13k
symptom_reports rows, there are 105 distinct symptom_ids. But the
first 8k symptom_reports rows only have 10 distinct symptom_ids.
Could this cause the problem and would there be anything I could do
to address it?
Thanks for all your help, I appreciate it.
-Jeff
---------------------------(end of broadcast)---------------------------
TIP 4: Have you searched our list archives?
http://archives.postgresql.org
