| From: | Amit Kapila <amit(dot)kapila(at)huawei(dot)com> |
|---|---|
| To: | "'Robert Haas'" <robertmhaas(at)gmail(dot)com>, "'Simon Riggs'" <simon(at)2ndquadrant(dot)com> |
| Cc: | "'Tom Lane'" <tgl(at)sss(dot)pgh(dot)pa(dot)us>, "'Pavan Deolasee'" <pavan(dot)deolasee(at)gmail(dot)com>, "'pgsql-hackers'" <pgsql-hackers(at)postgresql(dot)org> |
| Subject: | Re: Set visibility map bit after HOT prune |
| Date: | 2012-12-20 05:22:10 |
| Message-ID: | 004301cdde71$f7159570$e540c050$@kapila@huawei.com |
| Views: | Raw Message | Whole Thread | Download mbox | Resend email |
| Thread: | |
| Lists: | pgsql-hackers |
On Thursday, December 20, 2012 6:14 AM Robert Haas wrote:
> On Wed, Dec 19, 2012 at 12:39 PM, Simon Riggs <simon(at)2ndquadrant(dot)com>
> wrote:
> > The benefit of saying that only UPDATEs clean the block is that this
> > penalises only the workload making the mess, rather than everybody
> > cleaning up repeatedly over one messy guy.
>
> Right, but there are plenty of situations where having everybody clean
> up after the messy guy is better than waiting around and hoping that
> Mom (aka vacuum) will do it.
If we see for similar situation in index, during index scan, it just marks
the tuple as DEAD without taking X lock and then during split (when it
already has X lock) it free's the actual space.
So not sure if it's good idea to take X lock for cleanup during heap scan,
where write operation's happens more frequently and have better chance of
cleanup.
With Regards,
Amit Kapila.
| From | Date | Subject | |
|---|---|---|---|
| Next Message | Groshev Andrey | 2012-12-20 05:30:40 | Re: [GENERAL] trouble with pg_upgrade 9.0 -> 9.1 |
| Previous Message | Groshev Andrey | 2012-12-20 04:55:16 | Re: [GENERAL] trouble with pg_upgrade 9.0 -> 9.1 |