From: Tom Lane <tgl@sss.pgh.pa.us>
To: Nathan Bossart <nathandbossart@gmail.com>
cc: "Jonathan S. Katz" <jkatz@postgresql.org>,
        PostgreSQL Hackers <pgsql-hackers@lists.postgresql.org>
Subject: Re: Large expressions in indexes can't be stored (non-TOASTable)
In-reply-to: <ZtipsVMZAGjrO1p_@nathan>
References: <b611015f-b423-458c-aa2d-be0e655cc1b4@postgresql.org> <ZtipsVMZAGjrO1p_@nathan>
Comments: In-reply-to Nathan Bossart <nathandbossart@gmail.com>
	message dated "Wed, 04 Sep 2024 13:40:49 -0500"
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Date: Wed, 04 Sep 2024 15:08:13 -0400
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Nathan Bossart <nathandbossart@gmail.com> writes:
> Thanks to commit 96cdeae, only a few catalogs remain that are missing TOAST
> tables: pg_attribute, pg_class, pg_index, pg_largeobject, and
> pg_largeobject_metadata.  I've attached a short patch to add one for
> pg_index, which resolves the issue cited here.  This passes "check-world"
> and didn't fail for a few ad hoc tests (e.g., VACUUM FULL on pg_index).  I
> haven't spent too much time investigating possible circularity issues, but
> I'll note that none of the system indexes presently use the indexprs and
> indpred columns.

Yeah, the possibility of circularity seems like the main hazard, but
I agree it's unlikely that the entries for system indexes could ever
need out-of-line storage.  There are many other things that would have
to be improved before a system index could use indexprs or indpred.

			regards, tom lane