From: Patrick Stählin <patrick.staehlin@aiven.io>
To: Ronan Dunklau <ronan.dunklau@aiven.io>
To: Noah Misch <noah@leadboat.com>
To: Michael Paquier <michael@paquier.xyz>
Cc: pgsql-bugs <pgsql-bugs@lists.postgresql.org>
Subject: Re: FSM Corruption (was: Could not read block at end of the relation)
Date: Wed, 6 Mar 2024 11:59:43 +0100
Message-ID: <aede09f6-be0c-e10b-6a4f-c8e021a014c9@aiven.io> (raw)
In-Reply-To: <1958756.PYKUYFuaPT@aivenlaptop>
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<3609363.R56niFO833@aivenlaptop>
<1958756.PYKUYFuaPT@aivenlaptop>
On 3/6/24 10:31, Ronan Dunklau wrote:
> Le mardi 5 mars 2024, 00:05:03 CET Noah Misch a écrit :
>> I would guess this one is more risky from a performance perspective, since
>> we'd be adding to a hotter path under RelationGetBufferForTuple(). Still,
>> it's likely fine.
>
> I ended up implementing this in the attached patch. The idea is that we detect
> if the FSM returns a page past the end of the relation, and ignore it.
> In that case we will fallback through the extension mechanism.
@@ -582,7 +583,17 @@ RelationGetBufferForTuple(Relation relation, Size len,
* We have no cached target page, so ask the FSM for an initial
* target.
*/
+ nblocks = RelationGetNumberOfBlocks(relation);
targetBlock = GetPageWithFreeSpace(relation, targetFreeSpace);
I'd move the fetching of nblocks to after getting the targetBlock. This
avoids extending the relation in the unlikely event of a FSM/relation
extension in-between those two calls.
Patrick
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To: pgsql-bugs@postgresql.org
Cc: patrick.staehlin@aiven.io, ronan.dunklau@aiven.io, noah@leadboat.com, michael@paquier.xyz, pgsql-bugs@lists.postgresql.org
Subject: Re: FSM Corruption (was: Could not read block at end of the relation)
In-Reply-To: <aede09f6-be0c-e10b-6a4f-c8e021a014c9@aiven.io>
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