Re: SEARCH and CYCLE clauses

On 2020-09-22 20:29, Pavel Stehule wrote:
> The result is correct. When I tried to use UNION instead UNION ALL, the 
> pg crash

I fixed the crash, but UNION [DISTINCT] won't actually work here because 
row/record types are not hashable.  I'm leaving the partial support in, 
but I'm documenting it as currently not supported.

> looks so clause USING in cycle detection is unsupported for DB2 and 
> Oracle - the examples from these databases doesn't work on PG without 
> modifications

Yeah, the path clause is actually not necessary from a user's 
perspective, but it's required for internal bookkeeping.  We could 
perhaps come up with a mechanism to make it invisible coming out of the 
CTE (maybe give the CTE a target list internally), but that seems like a 
separate project.

The attached patch fixes the issues you have reported (also the view 
issue from the other email).  I have also moved the whole rewrite 
support to a new file to not blow up rewriteHandler.c so much.

-- 
Peter Eisentraut              http://www.2ndQuadrant.com/
PostgreSQL Development, 24x7 Support, Remote DBA, Training & Services