Hi,
Attached is a first version of the patch.
On Sunday, December 04, 2011 05:34:44 PM Tom Lane wrote:
> Andres Freund <andres@anarazel.de> writes:
> > I have two questions now:
> >
> > First, does anybody think it would be worth getting rid of the
> > duplication from OpenIntoRel (formerly from execMain.c) in regard to
> > DefineRelation()?
>
> That's probably reasonable to do, since as you say it would remove the
> opportunity for bugs-of-omission in the CTAS table creation step.
> OTOH, if you find yourself having to make any significant changes to
> DefineRelation, then maybe not.
Building a CreateStmt seems to work well enough so far.
The only problem with that approach so far that I found is that:
CREATE TABLE collate_test2 ( a int, b
textCOLLATE "POSIX"
);
CREATE TABLE collate_test1 ( a int, b
textCOLLATE "C" NOT NULL
);
CREATE TABLE test_u AS SELECT a, b FROM collate_test1 UNION ALL SELECT a, b
FROM collate_test2; -- fail
failed with:
ERROR: no collation was derived for column "b" with collatable type text
HINT: Use the COLLATE clause to set the collation explicitly.
"works" now.
I am currently setting ColumnDef.collOid of new collumns to attcollation of
the QueryDesc's column. Unfortunately they have a different meaning...
> > Secondly, I am currently wondering whether it would be a good idea to use
> > the ModifyTable infrastructure for doing the insertion instead an own
> > DestReceiver infrastructure thats only used for CTAS.
> I think this is probably a bad idea; it will complicate matters and buy
> little. There's not a lot of stuff needed for the actual data insertion
> step, since we know the table can't have any defaults, constraints,
> triggers, etc as yet.
I got to the same conclusion.
Remaining problems are:
* how to tell ExecContextForcesOids which oid we want
* implementing CREATE TABLE AS ... EXECUTE without duplicating ExecuteQuery
* the attcollation setting problems from above
* returning better error messages for using INTO at places its not allowed
Comments about the direction of the patch?
Andres
