Re: pg_upgrade and statistics

Bruce Momjian <bruce@momjian.us> writes:
> Copying the statistics from the old server is on the pg_upgrade TODO
> list.  I have avoided it because it will add an additional requirement
> that will make pg_upgrade more fragile in case of major version changes.

> Does anyone have a sense of how often we change the statistics data
> between major versions?

I don't think pg_statistic is inherently any more stable than any other
system catalog.  We've whacked it around significantly just last week,
which might color my perception a bit, but there are other changes on
the to-do list.  (For one example, see nearby complaints about
estimating TOAST-related costs, which we could not fix without adding
more stats data.)
        regards, tom lane