| From: | Peter Geoghegan <pg(at)bowt(dot)ie> |
|---|---|
| To: | Andres Freund <andres(at)anarazel(dot)de> |
| Cc: | Robert Haas <robertmhaas(at)gmail(dot)com>, Masahiko Sawada <sawada(dot)mshk(at)gmail(dot)com>, PostgreSQL Hackers <pgsql-hackers(at)lists(dot)postgresql(dot)org> |
| Subject: | Re: Removing more vacuumlazy.c special cases, relfrozenxid optimizations |
| Date: | 2022-02-20 03:40:20 |
| Message-ID: | CAH2-WzkkCgBZKSOhsgOPDaFJ7Ti_7LiMmjkb-9VVVc0XU5xV2A@mail.gmail.com |
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| Lists: | pgsql-hackers |
On Sat, Feb 19, 2022 at 7:28 PM Andres Freund <andres(at)anarazel(dot)de> wrote:
> If the vacuum can get the cleanup lock due to the adversarial patch, the
> heap_force_kill() doesn't do anything, because the first item is a
> redirect. However if it *can't* get a cleanup lock, heap_force_kill() instead
> targets the root item. Triggering the endless loop.
But it shouldn't matter if the root item is an LP_REDIRECT or a normal
(not heap-only) tuple with storage. Either way it's the root of a HOT
chain.
The fact that pg_surgery treats LP_REDIRECT items differently from the
other kind of root items is just arbitrary. It seems to have more to
do with freezing tuples than killing tuples.
--
Peter Geoghegan
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