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help / color / mirror / Atom feedFrom: David Rowley <[email protected]>
To: Tom Lane <[email protected]>
To: Richard Guo <[email protected]>
Cc: nikhil raj <[email protected]>
Cc: [email protected]
Subject: Re: Significant Execution Time Difference Between PG13.14 and PG16.4 for Query on information_schema Tables.
Date: Wed, 28 Aug 2024 11:03:08 +1200
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On Wed, 28 Aug 2024 at 09:52, Tom Lane <[email protected]> wrote:
> The other problem with this is that it breaks one test case in
> memoize.sql: a query that formerly generated a memoize plan
> now does not use memoize. I am not sure why not --- does that
> mean anything to you?
The reason it works in master is that get_memoize_path() calls
extract_lateral_vars_from_PHVs() and finds PlaceHolderVars to use as
the Memoize keys. With your patch PlannerInfo.placeholder_list is
empty.
The commit that made this work is 069d0ff02. Richard might be able to
explain better. I don't quite understand why RelOptInfo.lateral_vars
don't contain these in the first place.
David
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To: [email protected]
Cc: [email protected], [email protected], [email protected], [email protected], [email protected]
Subject: Re: Significant Execution Time Difference Between PG13.14 and PG16.4 for Query on information_schema Tables.
In-Reply-To: <CAApHDvp1mue1a5fdfsa2z2mAS6v2d9+kxMzxH7GhAiC0Z7o8Mw@mail.gmail.com>
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