Write operations in parallel mode

Now that dynamic shared memory hash table has been committed
(8c0d7bafad36434cb08ac2c78e69ae72c194ca20) I wonder if it's still a big deal
to remove restrictions like this in (e.g. heap_update()):

/*
* Forbid this during a parallel operation, lest it allocate a combocid.
* Other workers might need that combocid for visibility checks, and we
* have no provision for broadcasting it to them.
*/
if (IsInParallelMode())
ereport(ERROR,
(errcode(ERRCODE_INVALID_TRANSACTION_STATE),
errmsg("cannot update tuples during a
parallel operation")));

--
Antonin Houska
Cybertec Schönig & Schönig GmbH
Gröhrmühlgasse 26
A-2700 Wiener Neustadt
Web: http://www.postgresql-support.de, http://www.cybertec.at