From: | Amit Kapila <amit(dot)kapila16(at)gmail(dot)com> |
---|---|
To: | Robert Haas <robertmhaas(at)gmail(dot)com> |
Cc: | Michael Paquier <michael(dot)paquier(at)gmail(dot)com>, PostgreSQL mailing lists <pgsql-hackers(at)postgresql(dot)org>, Andres Freund <andres(at)anarazel(dot)de> |
Subject: | Re: Documentation fixes for pg_visibility |
Date: | 2016-07-07 05:41:15 |
Message-ID: | CAA4eK1KTMzwEJ2aSnyYZ15fo_Z5KRsNS7fqCcvUC37pMh6zp7Q@mail.gmail.com |
Views: | Raw Message | Whole Thread | Download mbox | Resend email |
Thread: | |
Lists: | pgsql-hackers |
On Tue, Jul 5, 2016 at 8:51 PM, Robert Haas <robertmhaas(at)gmail(dot)com> wrote:
>
> So I'm a bit confused about what you are saying here. If the page is
> marked all-frozen but actually isn't all-frozen, then we should clear
> the all-frozen bit in the VM.
>
Agreed.
> The easiest way to do that is to clear
> both bits in the VM plus the page-level bit, as done here, because we
> don't presently have a way of clearing just one of the visibility map
> bits.
>
Okay, but due to that we are clearing the visibility information
(all-visible) even though we should not clear it based on all-frozen.
I don't know if there is much harm even if we do the way it is
proposed in patch, but why not improve it if we can.
> Now, since the heap_lock_tuple issue requires us to introduce a new
> method to clear all-visible without clearing all-frozen, we could
> possibly use that here too, once we have it.
>
makes sense.
--
With Regards,
Amit Kapila.
EnterpriseDB: http://www.enterprisedb.com
From | Date | Subject | |
---|---|---|---|
Next Message | Michael Paquier | 2016-07-07 06:38:26 | Re: BUG #14230: Wrong timeline returned by pg_stop_backup on a standby |
Previous Message | Amit Kapila | 2016-07-07 05:11:04 | Re: Reviewing freeze map code |