Re: pg15b1: FailedAssertion("val > base", File: "...src/include/utils/relptr.h", Line: 67, PID: 30485) - Mailing list pgsql-hackers

From John Naylor
Subject Re: pg15b1: FailedAssertion("val > base", File: "...src/include/utils/relptr.h", Line: 67, PID: 30485)
Date
Msg-id CAFBsxsEAyM9ume5Kfxi6+Mnnhh66tHbxPo3b-25boTPixXMNCA@mail.gmail.com
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In response to Re: pg15b1: FailedAssertion("val > base", File: "...src/include/utils/relptr.h", Line: 67, PID: 30485)  (Robert Haas <robertmhaas@gmail.com>)
Responses Re: pg15b1: FailedAssertion("val > base", File: "...src/include/utils/relptr.h", Line: 67, PID: 30485)
List pgsql-hackers
On Wed, Jun 1, 2022 at 2:57 AM Robert Haas <robertmhaas@gmail.com> wrote:

> We do use fpm_segment_base(), but that accidentally fails
> to break, because instead of using relptr_access() it drills right
> through the abstraction and doesn't have any kind of special case for
> 0. So we can fix this by:
>
> 1. Using a relative pointer value other than 0 to represent a null
> pointer. Andres suggested (Size) -1.
> 2. Not storing the free page manager for the DSM in the main shared
> memory segment at byte offset 0.

Hi all,

For this open item, the above two ideas were discussed as a short-term
fix, and my reading of the thread is that the other proposals are too
invasive at this point in the cycle. Both of them have a draft patch
in the thread. #2, i.e. wasting MAXALIGN of space, seems the simplest
and most localized. Any thoughts on pulling the trigger on either of
these two approaches?

-- 
John Naylor
EDB: http://www.enterprisedb.com



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