Date: Thu, 13 Feb 2020 02:11:45 -0600
From: Justin Pryzby <pryzby@telsasoft.com>
To: Amit Langote <amitlangote09@gmail.com>
Cc: Alvaro Herrera <alvherre@2ndquadrant.com>, pgsql-hackers@postgresql.org
Subject: Re: assert pg_class.relnatts is consistent
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On Thu, Feb 13, 2020 at 04:51:01PM +0900, Amit Langote wrote:
> On Thu, Feb 13, 2020 at 3:23 AM Justin Pryzby <pryzby@telsasoft.com> wrote:
> > Forking this thread for two tangential patches which I think are more
> > worthwhile than the original topic's patch.
> > https://www.postgresql.org/message-id/20200207143935.GP403%40telsasoft.com
> >
> > Is there a better place to implement assertion from 0002 ?
> 
> I would think the answer to that would be related to the answer of why
> you think we need this assert in the first place?
> 
> I know I have made the mistake of not updating relnatts when I added
> relispartition, etc. to pg_class, only to be bitten by it in the form
> of seemingly random errors/crashes.  Is that why?

Right.  If adding or removing a column from pg_class (or others) it's necessary
not only to add the column in the .h file, and update references like Anum_*,
but also to update that catalog's own pg_class.relnatts in pg_class.dat.

On the other thead, Alvaro agreed it might be worth experimenting with moving
"indisclustered" from boolean in pg_index to an Oid in pg_class.  There's not
many references to it, so I was able to make most of the necessary changes
within an hour .. but spent some multiple of that tracing the crash in initdb,
which I would prefer to have failed less obscurely.

-- 
Justin