| From: | Simon Riggs <simon(at)2ndQuadrant(dot)com> |
|---|---|
| To: | Alvaro Herrera <alvherre(at)commandprompt(dot)com> |
| Cc: | Jaime Casanova <jcasanov(at)systemguards(dot)com(dot)ec>, pgsql-hackers <pgsql-hackers(at)postgresql(dot)org> |
| Subject: | Re: Preventing index scans for non-recoverable index AMs |
| Date: | 2008-12-18 02:56:57 |
| Message-ID: | 1229569017.4793.302.camel@ebony.2ndQuadrant |
| Views: | Raw Message | Whole Thread | Download mbox | Resend email |
| Thread: | |
| Lists: | pgsql-hackers |
On Wed, 2008-12-17 at 23:28 -0300, Alvaro Herrera wrote:
> Hmm, it doesn't seem like you understood my suggestion ... basically I'm
> saying that a hash index insert/delete should put out this WAL record:
>
> HEAP update address-of-pg_index-tuple set indisvalid=false
>
> (I'm just guessing at indisvalid but you get my point)
That would be simple and I'm very sorry to say I still don't think it
would work. But yes, I did misunderstand you.
In-progress hash index scans would not be prevented from executing by
the WAL record, so you might end up following a bad pointer. We probably
wouldn't want to try killing anybody using index either, since that
would end up as a complete bloodbath.
--
Simon Riggs www.2ndQuadrant.com
PostgreSQL Training, Services and Support
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