Re: [PATCH] Covering SPGiST index - Mailing list pgsql-hackers

From Andrey M. Borodin
Subject Re: [PATCH] Covering SPGiST index
Date
Msg-id D451983A-D629-4C1F-9FED-678D6D951684@yandex-team.ru
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In response to Re: [PATCH] Covering SPGiST index  (Pavel Borisov <pashkin.elfe@gmail.com>)
Responses Re: [PATCH] Covering SPGiST index  (Pavel Borisov <pashkin.elfe@gmail.com>)
List pgsql-hackers
Hi!

> 17 авг. 2020 г., в 21:04, Pavel Borisov <pashkin.elfe@gmail.com> написал(а):
>
> Postgres Professional: http://postgrespro.com
> <v6-0001-Covering-SP-GiST-index-support-for-INCLUDE-column.patch>

I'm looking into the patch. I have few notes:

1. I see that in src/backend/access/spgist/README you describe SP-GiST tuple as sequence of {Value, ItemPtr to heap,
Includedattributes}. Is it different from regular IndexTuple where tid is within TupleHeader? 

2. Instead of cluttering tuple->nextOffset with bit flags we could just change Tuple Header for leaf tuples with
coveringindexes. Interpret tuples for indexes with included attributes differently, iff it makes code cleaner. There
areso many changes with SGLT_SET_OFFSET\SGLT_GET_OFFSET that it seems viable to put some effort into research of other
waysto represent two bits for null mask and varatts. 

3. Comment "* SPGiST dead tuple: declaration for examining non-live tuples" does not precede relevant code. because
structSpGistDeadTupleData was not moved. 

Thanks!

Best regards, Andrey Borodin.


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