Re: REINDEX : new parameter to preserve current average leaf densityas new implicit FILLFACTOR - Mailing list pgsql-general

From John Lumby
Subject Re: REINDEX : new parameter to preserve current average leaf densityas new implicit FILLFACTOR
Date
Msg-id BYAPR06MB555963F83B69BCACBCA703F9A3F10@BYAPR06MB5559.namprd06.prod.outlook.com
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In response to Re: REINDEX : new parameter to preserve current average leaf densityas new implicit FILLFACTOR  (Peter Geoghegan <pg@bowt.ie>)
Responses Re: REINDEX : new parameter to preserve current average leaf densityas new implicit FILLFACTOR  (Peter Geoghegan <pg@bowt.ie>)
List pgsql-general
> From: Peter Geoghegan <pg@bowt.ie>
> Sent: July 8, 2019 1:39 PM
> Subject: Re: REINDEX : new parameter to preserve current average leaf density as new implicit FILLFACTOR
>
> On Mon, Jul 8, 2019 at 9:23 AM John Lumby <johnlumby@hotmail.com> wrote:
>
> > Although a welcome improvement,  I think it is not enough to justify stopping use of setting
> > a lower explicit FILLFACTOR.   Which then brings me back to  thinking there is a case
> > for the subject of this thread,  an automatic way to preserve density.
>
> I don't think that such an option would make much sense. The "waves of
> misery" paper is about smoothing out the frequency of page splits
> following bulk loading and a CREATE INDEX. It is not about making
> splits occur less often. It's well understood that a certain amount of
> free space is the overhead of B-Tree indexes, albeit an overhead that
> can be avoided in certain specific instances.
>
Yes,   I see that.     But surely "making splits occur less often" is a desirable
objective in itself, is it not?     And I believe that a parameter to preserve the "steady-state"
density in high-traffic indexes would help achieve that goal,   wouldn't you agree?

Cheers,  John Lumby




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