Re: pg_am.amstrategies should be 0 when not meaningful?

Teodor Sigaev <teodor(at)sigaev(dot)ru> writes:
>> I propose that we should set pg_am.amstrategies to zero when the index
>> AM doesn't have a fixed interpretation of strategy numbers. This would
>> make it clearer that there's no intended upper bound. It would also

> Agreed. BTW, that also plays around possibility of grouping operator
> classes - since GIN/GiST hasn't fixed strategy numbers, they opclasses
> can not be unioned into group without extra agreement.

Sure, but a group has to have agreement on semantics anyway ---
agreement on operator numbering would be part of that.

BTW, I've been looking at the built-in GIN array opclasses and wondering
if we couldn't make them a group. The advantage is that we'd need only
one pg_amop entry for each of the anyarray operators that are common to
all those classes. But you could also see that as a disadvantage,
because if the operators are "loose" in the group then there's no clear
indication that the individual opclasses depend on them. OTOH all these
entries will be marked pinned in pg_depend and so are undroppable, so
that disadvantage is largely academic.

regards, tom lane