Re: Hybrid Hash/Nested Loop joins and caching results from subplans
David Rowley <dgrowleyml@gmail.com>
From: David Rowley <dgrowleyml@gmail.com>
To: Robert Haas <robertmhaas@gmail.com>
Cc: PostgreSQL Developers <pgsql-hackers@lists.postgresql.org>
Date: 2020-08-05T22:00:31Z
Lists: pgsql-hackers
On Thu, 6 Aug 2020 at 08:13, Robert Haas <robertmhaas@gmail.com> wrote: > > This is cool work; I am going to bikeshed on the name for a minute. I > don't think Result Cache is terrible, but I have two observations: Thanks > 1. It might invite confusion with a feature of some other database > systems where they cache the results of entire queries and try to > reuse the entire result set. Yeah. I think "Cache" is good to keep, but I'm pretty much in favour of swapping "Result" for something else. It's a bit too close to the "Result" node in name, but too distant for everything else. > 2. The functionality reminds me a bit of a Materialize node, except > that instead of overflowing to disk, we throw away cache entries, and > instead of caching just one result, we potentially cache many. > > I can't really think of a way to work Materialize into the node name > and I'm not sure it would be the right idea anyway. But I wonder if > maybe a name like "Parameterized Cache" would be better? Yeah, I think that name is better. The only downside as far as I can see is the length of it. I'll hold off a bit before doing any renaming though to see what other people think. I just feel bikeshedding on the name is something that's going to take up quite a bit of time and effort with this. I plan to rename it at most once. Thanks for the comments David
Commits
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Add Result Cache executor node (take 2)
- 9eacee2e62d8 14.0 landed
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Add Result Cache executor node
- b6002a796dc0 14.0 landed
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Allow estimate_num_groups() to pass back further details about the estimation
- ed934d4fa30f 14.0 landed
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Allow users of simplehash.h to perform direct deletions
- ff53d7b159b9 14.0 landed
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Cache if PathTarget and RestrictInfos contain volatile functions
- f58b230ed0db 14.0 landed
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Fix pull_varnos' miscomputation of relids set for a PlaceHolderVar.
- 55dc86eca70b 14.0 cited