Re: GUC for cleanup indexes threshold.

Amit Kapila <amit.kapila16@gmail.com>

From: Amit Kapila <amit.kapila16@gmail.com>
To: Peter Geoghegan <pg@bowt.ie>
Cc: Robert Haas <robertmhaas@gmail.com>, Masahiko Sawada <sawada.mshk@gmail.com>, Simon Riggs <simon@2ndquadrant.com>, "Ideriha, Takeshi" <ideriha.takeshi@jp.fujitsu.com>, PostgreSQL-development <pgsql-hackers@postgresql.org>, Kuntal Ghosh <kuntalghosh.2007@gmail.com>
Date: 2017-02-25T03:38:10Z
Lists: pgsql-hackers
On Sat, Feb 25, 2017 at 3:40 AM, Peter Geoghegan <pg@bowt.ie> wrote:
> On Fri, Feb 24, 2017 at 9:26 AM, Robert Haas <robertmhaas@gmail.com> wrote:
>> I think this thread is pretty short on evidence that would let us make
>> a smart decision about what to do here.  I see three possibilities.
>> The first is that this patch is a good idea whether we do something
>> about the issue of half-dead pages or not.  The second is that this
>> patch is a good idea if we do something about the issue of half-dead
>> pages but a bad idea if we don't.  The third is that this patch is a
>> bad idea whether or not we do anything about the issue of half-dead
>> pages.
>

+1.  I think we can track the stats from
IndexBulkDeleteResult->pages_free to see the impact of the patch.


> Half-dead pages are not really relevant to this discussion, AFAICT. I
> think that both you and Simon mean "recyclable" pages.
>

Yes, I think so and I think that is just confusion about terminology.


-- 
With Regards,
Amit Kapila.
EnterpriseDB: http://www.enterprisedb.com


Commits

  1. Fix upper limit for vacuum_cleanup_index_scale_factor

  2. Increase upper limit for vacuum_cleanup_index_scale_factor

  3. Fixes for vacuum_cleanup_index_scale_factor GUC option

  4. Skip full index scan during cleanup of B-tree indexes when possible