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Message-ID: <3e128ea7-8cae-4a48-9d7c-9a032e7633f4@iki.fi>
Date: Sat, 3 Oct 2026 00:55:25 +0300
MIME-Version: 1.0
User-Agent: Mozilla Thunderbird
Subject: Re: BUG #19628: Uninterruptible vacuum during hash index processing
To: mostafa nabil <mostafa.nabil.nafie@gmail.com>,
 Kirill Reshke <reshkekirill@gmail.com>, pgsql-bugs@lists.postgresql.org,
 sk@zsrv.org
References: <19628-c2b17d358181a1ea@postgresql.org>
 <CAOwWfmwvEfJ+_-AQdX_+F_ffRBeTxQn_ru1s19ppX_qTeHnWYg@mail.gmail.com>
 <CALdSSPhMOpUYFFViHSZma=enFkGjjp-T_xoBGGrmL3TNTS+REA@mail.gmail.com>
 <CAOwWfmycksenYFimk-ohmk4Q+tPzUurnaAJ7WD+N-do=TdPs3A@mail.gmail.com>
 <CAOwWfmy+7Xgu_8O0iWZ8-hnXedhW=0Kv2yqO0yNXVbc6_g3H2A@mail.gmail.com>
 <CAOwWfmw2u4NUy6S9e+zbt2tOMD3LhmEq5PXiwag6SxTWs9qgnQ@mail.gmail.com>
Content-Language: en-US
From: Heikki Linnakangas <hlinnaka@iki.fi>
In-Reply-To: 
 <CAOwWfmw2u4NUy6S9e+zbt2tOMD3LhmEq5PXiwag6SxTWs9qgnQ@mail.gmail.com>
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On 02/10/2026 12:21, mostafa nabil wrote:
> Hi Kirill,
> 
> Thanks again for the review. Did you get a chance to look at v2? It
> removes the vacuum_delay_point() call in hashbucketcleanup() as you
> suggested, and keeps the check at the top of hashbulkdelete()'s
> per-bucket loop.

I had a look at this. Some further fixes:

Do we have more places where we call vacuum_delay_point() while holding 
locks? It seems like a bad idea to ever do that -- you don't want to 
sleep while holding locks. I added an 
"Assert(INTERRUPTS_CAN_BE_PROCESSED())" into vacuum_cost_delay() and ran 
the regression tests, and that indeed revealed a few more places that 
did that. The attached patch removes or moves those vacuum_delay_point() 
calls too. I didn't include the assertion in the patch, because I'm 
afraid there might be more places that we've missed, including in 
extensions.

After fixing those, if you ever do call vacuum_cost_delay_point() while 
holding a lock, e.g. from an extension or if we missed a caller, I think 
you don't really want to sleep. And you definitely don't want to call 
ProcessConfigFile() while in a critical section. So I added a quick exit 
to vacuum_delay_point() if it's called with !INTERRUPTS_CAN_BE_PROCESSED().

What do you think?

- Heikki

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