Erwin Brandstetter <brsaweda(at)gmail(dot)com> writes:
>> The following operations are always parallel restricted.
>> - Scans of common table expressions (CTEs).
> Now I am unsure whether I can use `PARALLEL SAFE` for functions containing
> a CTE (while fulfilling all other criteria)?
AFAIR, the reason for treating CTEs as parallel restricted is simply to
guarantee single evaluation of the CTE. Within a function, that would
only matter per-function-execution, so I can't see why a function
containing such a query couldn't be pushed down to workers for execution.
regards, tom lane