Date: Fri, 26 Oct 2018 11:09:27 -0300
From: Alvaro Herrera <alvherre@2ndquadrant.com>
To: Tom Lane <tgl@sss.pgh.pa.us>
Cc: Amit Langote <Langote_Amit_f8@lab.ntt.co.jp>,
	Bruno Wolff III <bruno@wolff.to>,
	pgsql-general@lists.postgresql.org,
	pgsql-hackers@lists.postgresql.org
Subject: Re: Should pg 11 use a lot more memory building an spgist index?
Message-ID: <20181026140927.oh4gd367st47li6h@alvherre.pgsql>
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On 2018-Oct-26, Tom Lane wrote:

> After a quick look around, I think that making systable_begin/endscan
> do this is a nonstarter; there are just too many call sites that would
> be affected.  Now, you could imagine specifying that indexes on system
> catalogs (in practice, only btree) have to clean up at endscan time
> but other index types don't, so that only operations that might be
> scanning user indexes need to have suitable wrapping contexts.  Not sure
> there's a lot of benefit to that, though.

How about modifying SysScanDescData to have a memory context member,
which is created by systable_beginscan and destroyed by endscan?

-- 
Álvaro Herrera                https://www.2ndQuadrant.com/
PostgreSQL Development, 24x7 Support, Remote DBA, Training & Services