Re: Add index scan progress to pg_stat_progress_vacuum

On 1/11/22, 11:46 PM, "Masahiko Sawada" <sawada.mshk@gmail.com> wrote:
> Regarding the new pg_stat_progress_vacuum_index view, why do we need
> to have a separate view? Users will have to check two views. If this
> view is expected to be used together with and joined to
> pg_stat_progress_vacuum, why don't we provide one view that has full
> information from the beginning? Especially, I think it's not useful
> that the total number of indexes to vacuum (num_indexes_to_vacuum
> column) and the current number of indexes that have been vacuumed
> (index_ordinal_position column) are shown in separate views.

I suppose we could add all of the new columns to
pg_stat_progress_vacuum and just set columns to NULL as appropriate.
But is that really better than having a separate view?

> Also, I’m not sure how useful index_tuples_removed is; what can we
> infer from this value (without a total number)?

I think the idea was that you can compare it against max_dead_tuples
and num_dead_tuples to get an estimate of the current cycle progress.
Otherwise, it just shows that progress is being made.

Nathan

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