Piotr Findeisen <piotr.findeisen@starburstdata.com> writes:
> Internally, array types get a name in the form of `_<typename>`.
Typically, yes.
> *Can a user use `_<typename>` to define a column of array type?*
Sure ... didn't you try it?
> *Is it supported?*
Not really, because it's not guaranteed that the name looks like that.
There are various corner cases where something else would be generated,
either to avoid a collision, or because truncation is needed.
However, if you've taken the trouble to check what name actually got
assigned to the array type, it's perfectly valid to use that name.
> The reason I am asking is that e.g. int4[] and _int4 behave differently.
> Although they look the same, the have different pg_attribute.attndims.
Yeah. Nothing really cares about attndims though ... it's vestigial.
Perhaps we should remove it someday.
regards, tom lane