>
>
>> I think my initial reaction is to just refuse those special values, but
>> I'll look into the parsing code to see what can be done.
>>
>
> I noticed that the output function for pg_ndistinct casts that value to an
> integer before formatting it %d, so it's being treated as an integer even
> if it is not stored as one. After some consultation with Tomas, it made the
> most sense to just replicate this on the input side as well, and that is
> addressed in the patches below.
>
> I've updated and rebased the patches.
>
> The existing pg_ndistinct and pg_dependences formats were kept as-is. The
> formats are clumsy, more processing-friendly formats would be easier, but
> the need for such processing is minimal bordering on theoretical, so there
> is little impact in keeping the historical format.
>
> There are now checks to ensure that the pg_ndistinct or pg_dependencies
> value assigned to an extended statistics object actually makes sense for
> that object. What this amounts to is checking that for every attnum cited,
> the positive attnums are also ones found the in the stxkeys of the
> pg_statistic_ext tuple, and the negative attnums correspond do not exceed
> the number of expressions in the attnum. In other words, if the stats
> object has no expressions in it, then no negative numbers will be accepted,
> if it has 2 expressions than any value -3 or lower will be rejected, etc.
>
> All patches rebased to 71f17823ba010296da9946bd906bb8bcad6325bc.
>
A rebasing, and a few changes
* regnamespace and name parameters changed to statistics_schemaname as text
and statistics_name as text, so that there's one less thing that can
potentially fail in an upgrade
* schema lookup and stat name lookup failures now issue a warning and
return false, rather than ERROR
* elevel replaced with hardcoded WARNING most everywhere, as has been done
with relation/attribute stats