On 10.10.2020 08:25, Pavel Stehule wrote:
Hi
pá 9. 10. 2020 v 12:17 odesílatel Pavel Stehule
<pavel.steh...@gmail.com <mailto:pavel.steh...@gmail.com>> napsal:
pá 9. 10. 2020 v 11:40 odesílatel Peter Eisentraut
<peter.eisentr...@2ndquadrant.com
<mailto:peter.eisentr...@2ndquadrant.com>> napsal:
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.
I think so UNION is a common solution against the cycles. So
missing support for this specific case is not a nice thing. How
much work is needed for hashing rows. It should not be too much code.
> 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
This patch is based on transformation CYCLE and SEARCH clauses to
specific expressions - it is in agreement with ANSI SQL
There is not a problem with compilation
Nobody had objections in discussion
There are enough regress tests and documentation
check-world passed
doc build passed
I'll mark this patch as ready for committer
Possible enhancing for this feature (can be done in next steps)
1. support UNION DISTINCT
2. better compatibility with Oracle and DB2 (USING clause can be optional)
Regards
Pavel
Status update for a commitfest entry.
According to cfbot patch no longer applies. So I moved it to waiting on
author.
--
Anastasia Lubennikova
Postgres Professional: http://www.postgrespro.com
The Russian Postgres Company
