| From: | Tom Lane <tgl(at)sss(dot)pgh(dot)pa(dot)us> |
|---|---|
| To: | Hannu Krosing <hannu(at)skype(dot)net> |
| Cc: | PostgreSQL-development <pgsql-hackers(at)postgresql(dot)org> |
| Subject: | Re: Question about explain of index scan |
| Date: | 2005-09-02 15:31:49 |
| Message-ID: | 14586.1125675109@sss.pgh.pa.us |
| Views: | Raw Message | Whole Thread | Download mbox | Resend email |
| Thread: | |
| Lists: | pgsql-hackers |
Hannu Krosing <hannu(at)skype(dot)net> writes:
> On R, 2005-09-02 at 10:31 -0400, Tom Lane wrote:
>> Yes. However, I don't understand how you got that result; AFAIK the
>> planner should have eliminated the duplicate subclauses.
> the query was similar to this:
> [snip]
Oh, the OR arms are actually *not* equivalent because of the log_tableid
subclauses. So that explains why canonicalize_qual() didn't eliminate
them.
[ experiments... ] It looks like 8.0 and up are smart enough to
consolidate the identical extracted indexquals, but not 7.4.
regards, tom lane
| From | Date | Subject | |
|---|---|---|---|
| Next Message | Alvaro Herrera | 2005-09-02 15:38:10 | Re: Question about explain of index scan |
| Previous Message | Stephen Frost | 2005-09-02 15:23:43 | Re: GRANT/roles problem: grant is shown as from login role |