| From: | "Kevin Grittner" <Kevin(dot)Grittner(at)wicourts(dot)gov> |
|---|---|
| To: | <pgsql-performance(at)postgresql(dot)org>,<tgl(at)sss(dot)pgh(dot)pa(dot)us> |
| Cc: | <matthew(at)flymine(dot)org>,<jmpoure(at)free(dot)fr>, <craig(at)postnewspapers(dot)com(dot)au> |
| Subject: | Re: Order by (for 15 rows) adds 30 seconds to query time |
| Date: | 2009-12-26 20:15:10 |
| Message-ID: | 4B361A6E020000250002D965@gw.wicourts.gov |
| Views: | Raw Message | Whole Thread | Download mbox | Resend email |
| Thread: | |
| Lists: | pgsql-performance |
Tom Lane wrote:
> That does look weird. Do we have a self-contained test case?
I've been tinkering with this and I now have a self-contained test
case (SQL statements and run results attached). I've debugged through
it and things don't seem right in set_append_rel_pathlist, since
childrel->rows seems to contain the total rows in each table rather
than the number which meet the join conditions. That is reflected in
the output from OPTIMIZER_DEBUG logging, but not in the query plan
from ANALYZE?
I'm afraid I'm a bit stuck on getting farther. Hopefully this much
will be of use to someone. If you could point out where I should
have looked next, I'd be grateful. :-)
-Kevin
| Attachment | Content-Type | Size |
|---|---|---|
| testcase2.sql | application/octet-stream | 811 bytes |
| testcase2.out | application/octet-stream | 5.3 KB |
| testcase2.log | application/octet-stream | 2.5 KB |
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