function attribute_statsitics_update() is significantly shorter. (Thank you for a good set of tests, by the way, which sped up the refactoring process.)
yw
* Remind me why the new stats completely replace the new row, rather than updating only the statistic kinds that are specified?
because: - complexity
- we would then need a mechanism to then tell it to *delete* a stakind - we'd have to figure out how to reorder the remaining stakinds, or spend effort finding a matching stakind in the existing row to know to replace it - "do what analyze does" was an initial goal and as a result many test cases directly compared pg_statistic rows from an original table to an empty clone table to see if the "copy" had fidelity.
* I'm not sure what the type_is_scalar() function was doing before, but I just removed it. If it can't find the element type, then it skips over the kinds that require it.
that may be sufficient,
* I introduced some hard errors. These happen when it can't find the table, or the attribute, or doesn't have permissions. I don't see any reason to demote those to a WARNING. Even for the restore case, analagous errors happen for COPY, etc.
I can accept that reasoning.
* I'm still sorting through some of the type info derivations. I think we need better explanations about why it's doing exactly the things it's doing, e.g. for tsvector and multiranges.
I don't have the specifics of each, but any such cases were derived from similar behaviors in the custom typanalyze functions, and the lack of a custom typanalyze function for a given type was taken as evidence that the type was adequately handled by the default rules. I can see that this is an argument for having a second stats-specific custom typanalyze function for datatypes that need them, but I wasn't ready to go that far myself.
