On Tue, Oct 27, 2020 at 11:06:22AM -0300, Fabrízio de Royes Mello wrote:
> When we create a new table or index they will not have statistics until an
> ANALYZE happens. This is the default behaviour and I think is not a big
> problem here, but we need to add some note on docs about the need of
> statistics for indexes on expressions.
>
> But IMHO there is a misbehaviour with the implementation of CONCURRENTLY on
> REINDEX because running it will lose the statistics. Have a look the
> example below:
>
> [...]
>
> So IMHO here is the place we should rework a bit to execute ANALYZE as a
> last step.
I agree that this is not user-friendly, and I suspect that we will
need to do something within index_concurrently_swap() to fill in the
stats of the new index from the data of the old one (not looked at
that in details yet).
--
Michael