On Mon, Jun 03, 2024 at 03:24:07PM -0700, Andres Freund wrote:
> I'm confused - isn't using common/int.h entirely sufficient for that? Nearly
> all architectures have more efficient ways to check for 64bit overflows than
> doing actual 128 bit math.
One simple way to change the assertion would be
On Mon, Jun 03, 2024 at 03:24:07PM -0700, Andres Freund wrote:
> I'm confused - isn't using common/int.h entirely sufficient for that? Nearly
> all architectures have more efficient ways to check for 64bit overflows than
> doing actual 128 bit math.
Oh, right. We could just plug in pg_add_u32_ove
Hi,
On 2024-06-04 07:17:51 +0900, Michael Paquier wrote:
> On Sun, May 26, 2024 at 12:08:46AM -0400, Tom Lane wrote:
> > After a few minutes' thought, how about:
> >
> > Assert((uint64) blocknum + (uint64) nblocks <= (uint64) mdnblocks(reln,
> > forknum));
> >
> > This'd stop being helpful
On Sun, May 26, 2024 at 12:08:46AM -0400, Tom Lane wrote:
> After a few minutes' thought, how about:
>
> Assert((uint64) blocknum + (uint64) nblocks <= (uint64) mdnblocks(reln,
> forknum));
>
> This'd stop being helpful if we ever widen BlockNumber to 64 bits,
> but I think that's unlikely
On Sun, May 26, 2024 at 12:08:46AM -0400, Tom Lane wrote:
> After a few minutes' thought, how about:
>
> Assert((uint64) blocknum + (uint64) nblocks <= (uint64) mdnblocks(reln,
> forknum));
LGTM. Yeah that should be OK this way.
--
Michael
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I wrote:
> Hmm ... I agree that this is better normally. But there's an
> edge case where it would fail to notice a problem that the
> existing code does notice: if blocknum is close to UINT32_MAX
> and adding nblocks causes it to wrap around to a small value.
> Is there an inexpensive way to catc
Michael Paquier writes:
> On Sat, May 25, 2024 at 11:52:22PM +0800, Xing Guo wrote:
>> #ifdef CHECK_WRITE_VS_EXTEND
>> -Assert(blocknum < mdnblocks(reln, forknum));
>> +Assert(blocknum + nblocks <= mdnblocks(reln, forknum));
>> #endif
> Yes, it looks like you're right that this can be mad
On Sat, May 25, 2024 at 11:52:22PM +0800, Xing Guo wrote:
> In commit 4908c58[^1], a vectored variant of smgrwrite() is added and
> the assertion condition in mdwritev() no longer matches the comment.
> This patch helps fix it.
>
> /* This assert is too expensive to have on normally ... */
>
Hi hackers,
In commit 4908c58[^1], a vectored variant of smgrwrite() is added and
the assertion condition in mdwritev() no longer matches the comment.
This patch helps fix it.
[^1]:
https://github.com/postgres/postgres/commit/4908c5872059c409aa647bcde758dfeffe07996e
Best Regards,
Xing
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