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Date: Wed, 12 Oct 2022 15:49:56 +0200
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Subject: Re: ExecRTCheckPerms() and many prunable partitions
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To: Amit Langote <amitlangote09@gmail.com>, Tom Lane <tgl@sss.pgh.pa.us>
Cc: David Rowley <dgrowleyml@gmail.com>, Greg Stark <stark@mit.edu>,
 Zhihong Yu <zyu@yugabyte.com>, Julien Rouhaud <rjuju123@gmail.com>,
 Alvaro Herrera <alvherre@alvh.no-ip.org>,
 PostgreSQL Hackers <pgsql-hackers@lists.postgresql.org>
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From: Peter Eisentraut <peter.eisentraut@enterprisedb.com>
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On 06.10.22 15:29, Amit Langote wrote:
> I tried in the attached 0004.  ModifyTable gets a new member
> extraUpdatedColsBitmaps, which is List of Bitmapset "nodes".
> 
> Actually, List of Bitmapsets turned out to be something that doesn't
> just-work with our Node infrastructure, which I found out thanks to
> -DWRITE_READ_PARSE_PLAN_TREES.  So, I had to go ahead and add
> first-class support for copy/equal/write/read support for Bitmapsets,
> such that writeNode() can write appropriately labeled versions of them
> and nodeRead() can read them as Bitmapsets.  That's done in 0003.  I
> didn't actually go ahead and make*all*  Bitmapsets in the plan trees
> to be Nodes, but maybe 0003 can be expanded to do that.  We won't need
> to make gen_node_support.pl emit *_BITMAPSET_FIELD() blurbs then; can
> just use *_NODE_FIELD().

Seeing that on 64-bit platforms we have a 4-byte padding gap in the 
Bitmapset struct, sticking a node tag in there seems pretty sensible. 
So turning Bitmapset into a proper Node and then making the other 
adjustments you describe makes sense to me.

Making a new thread about this might be best.

(I can't currently comment on the rest of the patch set.  So I don't 
know if you'll really end up needing lists of bitmapsets.  But from here 
it looks like turning bitmapsets into nodes might be a worthwhile change 
just by itself.)