Date: Fri, 1 Sep 2023 13:52:48 -0700
From: Nathan Bossart <nathandbossart@gmail.com>
To: Robert Haas <robertmhaas@gmail.com>
Cc: Tom Lane <tgl@sss.pgh.pa.us>, Alvaro Herrera <alvherre@alvh.no-ip.org>,
	Andrew Dunstan <andrew@dunslane.net>,
	pgsql-hackers@lists.postgresql.org
Subject: Re: Inefficiency in parallel pg_restore with many tables
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On Fri, Sep 01, 2023 at 04:00:44PM -0400, Robert Haas wrote:
> In hindsight, I think that making binaryheap depend on Datum was a bad
> idea. I think that was my idea, and I think it wasn't very smart.
> Considering that people have coded to that decision up until now, it
> might not be too easy to change at this point. But in principle I
> guess you'd want to be able to make a heap out of any C data type,
> rather than just Datum, or just Datum in the backend and just void *
> in the frontend.

Yeah, something similar to simplehash for binary heaps could be nice.  That
being said, I don't know if there's a strong reason to specialize the
implementation for a given C data type in most cases.  I suspect many
callers are just fine with dealing with pointers (e.g., I wouldn't store an
entire TocEntry in the array), and smaller types like integers are already
stored directly in the array thanks to the use of Datum.  However, it
_would_ allow us to abandon this frontend/backend void */Datum kludge,
which is something.

-- 
Nathan Bossart
Amazon Web Services: https://aws.amazon.com