| From: | Tom Lane <tgl(at)sss(dot)pgh(dot)pa(dot)us> |
|---|---|
| To: | Alvaro Herrera <alvherre(at)commandprompt(dot)com> |
| Cc: | Andrew Dunstan <andrew(at)dunslane(dot)net>, Jeff Janes <jeff(dot)janes(at)gmail(dot)com>, "David E(dot) Wheeler" <david(at)justatheory(dot)com>, Pg Hackers <pgsql-hackers(at)postgresql(dot)org> |
| Subject: | Re: Covering Indexes |
| Date: | 2012-06-28 16:32:43 |
| Message-ID: | 14811.1340901163@sss.pgh.pa.us |
| Views: | Raw Message | Whole Thread | Download mbox | Resend email |
| Thread: | |
| Lists: | pgsql-hackers |
Alvaro Herrera <alvherre(at)commandprompt(dot)com> writes:
> The other question is whether such an index would prevent an update from
> being HOT when the non-indexed values are touched.
Surely it would *have* to, whether the columns are significant or not
for uniqueness purposes. Else an index-only scan gives the wrong value
after the update.
regards, tom lane
| From | Date | Subject | |
|---|---|---|---|
| Next Message | Jeff Janes | 2012-06-28 16:46:22 | Re: Posix Shared Mem patch |
| Previous Message | Josh Kupershmidt | 2012-06-28 16:32:41 | Re: pg_signal_backend() asymmetry |