| From: | Robert Haas <robertmhaas(at)gmail(dot)com> |
|---|---|
| To: | Simon Riggs <simon(at)2ndquadrant(dot)com> |
| Cc: | Michael Paquier <michael(dot)paquier(at)gmail(dot)com>, PostgreSQL mailing lists <pgsql-hackers(at)postgresql(dot)org> |
| Subject: | Re: Minimum tuple threshold to decide last pass of VACUUM |
| Date: | 2015-08-03 17:33:01 |
| Message-ID: | CA+TgmoZ19zMc=y0f3wipkE=RGGUJb63_y9Q2Wa5mK4fRr_XW4Q@mail.gmail.com |
| Views: | Raw Message | Whole Thread | Download mbox | Resend email |
| Thread: | |
| Lists: | pgsql-hackers |
On Mon, Aug 3, 2015 at 4:13 AM, Simon Riggs <simon(at)2ndquadrant(dot)com> wrote:
> * For normal VACUUMs we should scan indexes only if (num_dead_tuples * 20) >
> (blocks to be scanned in any one index), which allows some index bloat but
> not much
I think this kind of heuristic is good, but I think we should expose a
setting for it. There's no way for us to know without testing whether
the right value for that multiplier is 2 or 20 or 200 or 2000, and if
we don't make it easy to tweak, we'll never find out. It may even be
workload-dependent.
--
Robert Haas
EnterpriseDB: http://www.enterprisedb.com
The Enterprise PostgreSQL Company
| From | Date | Subject | |
|---|---|---|---|
| Next Message | Peter Geoghegan | 2015-08-03 17:39:39 | Re: ON CONFLICT DO UPDATE using EXCLUDED.column gives an error about mismatched types |
| Previous Message | Robert Haas | 2015-08-03 17:31:23 | Re: Minimum tuple threshold to decide last pass of VACUUM |