Re: Skip ExecCheckRTPerms in CTAS with no data

On Wed, Nov 11, 2020 at 07:31:49PM +0530, Bharath Rupireddy wrote:
> Yes we do not have anything related to permissions mentioned in the
> documentation. So, I'm not adding it now.

It would be good to clarify that in the docs while we are on it.

> Apart from the above, I also noticed that we unnecessarily allocate
> bulk insert state(16MB memory) in case of WITH NO DATA, just to free
> it in intorel_shutdown() without actually using it. So, in the v2
> patch I have made changes to not allocate bulk insert state.
> 
> Attaching v2 patch. Consider it for further review.

+EXPLAIN (ANALYZE, COSTS OFF, SUMMARY OFF, TIMING OFF)
+	CREATE TABLE selinto_schema.tmp0 (a) AS
+    SELECT oid FROM pg_class WHERE relname like '%c%' WITH NO DATA; -- OK

I don't think this is sufficient.  Could you add more test cases here?
I can think of, coming down actually to the callers of
CreateIntoRelDestReceiver:
- A plain CTAS WITH NO DATA, that should pass,
- CTAS EXECUTE WITH NO DATA, that should pass.
- CTAS EXECUTE WITH DATA, that should not pass.
- EXPLAIN CTAS WITH DATA, that should not pass.
--
Michael