Re: Faulty HEAP_XMAX_LOCK_ONLY & HEAP_KEYS_UPDATED hintbit combination

On 2021-Jan-24, Julien Rouhaud wrote:

> + /*
> + * Do not allow tuples with invalid combinations of hint bits to be placed
> + * on a page. These combinations are detected as corruption by the
> + * contrib/amcheck logic, so if you disable one or both of these
> + * assertions, make corresponding changes there.
> + */
> + Assert(!((tuple->t_data->t_infomask & HEAP_XMAX_LOCK_ONLY) &&
> + (tuple->t_data->t_infomask2 & HEAP_KEYS_UPDATED)));
>
>
> I attach a simple self contained script to reproduce the problem, the last
> UPDATE triggering the Assert.
>
> I'm not really familiar with this part of the code, so it's not exactly clear
> to me if some logic is missing in compute_new_xmax_infomask() /
> heap_prepare_insert(), or if this should actually be an allowed combination of
> hint bit.

Hmm, it's probably a bug in compute_new_xmax_infomask. I don't think
the combination is sensible.

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Álvaro Herrera 39°49'30"S 73°17'W
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