From: | Robert Haas <robertmhaas(at)gmail(dot)com> |
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To: | Andres Freund <andres(at)anarazel(dot)de> |
Cc: | "Drouvot, Bertrand" <bertranddrouvot(dot)pg(at)gmail(dot)com>, Alvaro Herrera <alvherre(at)2ndquadrant(dot)com>, Ibrar Ahmed <ibrar(dot)ahmad(at)gmail(dot)com>, Amit Khandekar <amitdkhan(dot)pg(at)gmail(dot)com>, fabriziomello(at)gmail(dot)com, tushar <tushar(dot)ahuja(at)enterprisedb(dot)com>, Rahila Syed <rahila(dot)syed(at)2ndquadrant(dot)com>, pgsql-hackers <pgsql-hackers(at)postgresql(dot)org> |
Subject: | Re: Minimal logical decoding on standbys |
Date: | 2022-12-20 21:41:54 |
Message-ID: | CA+TgmoYTTsxP8y6uknZvCBNCRq+1FJ4zGbX8Px1TGW459fGsaQ@mail.gmail.com |
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On Tue, Dec 20, 2022 at 3:39 PM Robert Haas <robertmhaas(at)gmail(dot)com> wrote:
> I think this might be the only WAL record type where there's a
> problem, but I haven't fully confirmed that yet.
It's not. GIST has the same issue. The same test case demonstrates the
problem there, if you substitute this test script for
kpt_hash_setup.sql and possibly also run it for somewhat longer. One
might think that this wouldn't be a problem, because the comments for
gistxlogDelete say this:
/*
* In payload of blk 0 : todelete OffsetNumbers
*/
But it's not in the payload of blk 0. It follows the main payload.
This is the reverse of xl_heap_freeze_page, which claims that freeze
plans and offset numbers follow, but they don't: they're in the data
for block 0. xl_btree_delete is also wrong, claiming that the data
follows when it's really attached to block 0. I guess whatever else we
do here, we should fix the comments.
Bottom line is that I think the two cases that have alignment issues
as coded are xl_hash_vacuum_one_page and gistxlogDelete. Everything
else is OK, as far as I can tell right now.
--
Robert Haas
EDB: http://www.enterprisedb.com
Attachment | Content-Type | Size |
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kpt_gist_setup.sql | application/octet-stream | 445 bytes |
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