Re: [HACKERS] [PATCH] kNN for SP-GiST - Mailing list pgsql-hackers

From Andrey Borodin
Subject Re: [HACKERS] [PATCH] kNN for SP-GiST
Date
Msg-id 13EDC8D7-A7DA-47ED-80B8-B48E01023633@yandex-team.ru
Whole thread Raw
In response to Re: [HACKERS] [PATCH] kNN for SP-GiST  (Andrey Borodin <x4mmm@yandex-team.ru>)
Responses Re: [HACKERS] [PATCH] kNN for SP-GiST  (Nikita Glukhov <n.gluhov@postgrespro.ru>)
List pgsql-hackers
Hi!

> I'm reviewing this patch. Currently I'm trying to understand sp-gist scan deeeper, but as for now have some small
notices.

I've passed through the code one more time. Here are few more questions:
1. Logic behind division of the patch into steps is described last time 2017-01-30, but ISTM actual steps have changed
sincethan? May I ask you to write a bit about steps of the patchset? 
2. The patch leaves contribs intact. Do extensions with sp-gist opclasses need to update it's behavior somehow to be
usedas-is? Or to support new functionality? 
3. There is a patch about predicate locking in SP-GiST [0] Is this KNN patch theoretically compatible with predicate
locking?Seems like it is, I just want to note that this functionality may exist. 
4. Scan state now have scanStack and queue. May be it's better to name scanStack and scanQueue or stack and queue?

Best regards, Andrey Borodin.

[0] https://commitfest.postgresql.org/14/1215/

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