Re: BUG #19006: Assert(BufferIsPinned) in BufferGetBlockNumber() is triggered for forwarded buffer

Xuneng Zhou <xunengzhou@gmail.com>

From: Xuneng Zhou <xunengzhou@gmail.com>
To: Michael Paquier <michael@paquier.xyz>
Cc: Tom Lane <tgl@sss.pgh.pa.us>, Thomas Munro <thomas.munro@gmail.com>, exclusion@gmail.com, pgsql-bugs@lists.postgresql.org
Date: 2025-08-07T11:37:19Z
Lists: pgsql-bugs

Commits

Same data as JSON: GET /api/v1/messages/:b64id/commits the thread's linked commits as JSON, with link sources. API reference →
  1. Fix rare bug in read_stream.c's split IO handling.

Hi,

On Wed, Aug 6, 2025 at 4:40 PM Michael Paquier <michael@paquier.xyz> wrote:
>
> On Tue, Aug 05, 2025 at 12:43:06AM -0400, Tom Lane wrote:
> > I've not looked at the issue actually being fixed, but a drive-by
> > comment: these loops
> >
> > +     for (int i = 0; i < stream->forwarded_buffers; ++i)
> > +             Assert(BufferGetBlockNumber(stream->buffers[stream->next_buffer_index + i]) ==
> > +                        stream->pending_read_blocknum + i);
> >
> > should be wrapped in "#ifdef USE_ASSERT_CHECKING".  Maybe the
> > compiler is smart enough to throw away the useless looping logic
> > in a production build, or maybe it isn't.
>
> I'd bet it is usually not that smart..  Embedding these in an extra
> #ifdef is a sound defense IMO.
> --
> Michael

+1

Best,
Xuneng