On Tue, May 3, 2016 at 11:36 AM, Tom Lane <tgl@sss.pgh.pa.us> wrote:
>> There are a lot more than 2 patchsets that are busted at the moment,
>> unfortunately, but I assume you are referring to "snapshot too old"
>> and "Use Foreign Key relationships to infer multi-column join
>> selectivity".
>
> Yeah, those are the ones I'm thinking of. I've not heard serious
> proposals to revert any others, have you?
Here's a list of what I think is currently broken in 9.6 that we might
conceivably fix by reverting patches:
- Snapshot Too Old. Tom, Andres, and Bruce want this reverted. It
regresses performance significantly when turned on. It originally
regressed performance significantly even when turned off, but that
might be fixed now. Also, it seems to be broken for hash indexes, per
Amit Kapila's report.
- Atomic Pin/Unpin. There are two different open items related to
this, both apparently relating to testing done by Jeff Janes. I am
not sure whether they are really independent reports of different
problems or just two reports of the same problem. But they sound like
fairly serious breakage.
- Predefined Roles. Neither you nor I liked Stephen's design. It
slowed down pg_dump. It also broke pg_dump for non-superusers and
something about bypassrls. None of these issues have been fixed
despite considerable time having gone by.
- Checkpoint Sorting and Flushing. Andres tried to fix the last
report of problems with this in
72a98a639574d2e25ed94652848555900c81a799, but there were almost
immediately new reports.
- Foreign Keys and Multi-Column Outer Joins. You called for a revert,
and the author responded with various thoughts and counterproposals.
There are a few other open items, but I would consider reverting the
antecedent patches as either impractical or disproportionate in those
cases. Aside from the two cases you mentioned, I don't think that
anyone's actually called for these other patches to be reverted, but
I'm not sure that we shouldn't be considering it. What do you (and
others) think?
--
Robert Haas
EnterpriseDB: http://www.enterprisedb.com
The Enterprise PostgreSQL Company