| From: | Andrew Gierth <andrew(at)tao11(dot)riddles(dot)org(dot)uk> |
|---|---|
| To: | Huong Dangminh <huo-dangminh(at)ys(dot)jp(dot)nec(dot)com> |
| Cc: | "pgsql-hackers\(at)lists(dot)postgresql(dot)org" <pgsql-hackers(at)lists(dot)postgresql(dot)org>, Hiroshi Yanagisawa <hir-yanagisawa(at)ut(dot)jp(dot)nec(dot)com>, Andres Freund <andres(at)anarazel(dot)de> |
| Subject: | Re: PostgreSQL 10: Segmentation fault when using GROUPING SETS with all unsortable columns |
| Date: | 2018-03-20 08:38:45 |
| Message-ID: | 87zi33f8pq.fsf@news-spur.riddles.org.uk |
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| Lists: | pgsql-hackers |
>>>>> "Huong" == Huong Dangminh <huo-dangminh(at)ys(dot)jp(dot)nec(dot)com> writes:
Huong> Hi,
Huong> I have found a case which could get segmentation fault when
Huong> using GROUPING SETS. It occurs when columns in GROUPING SETS are
Huong> all unsortable but hashable.
Yes, mea culpa. will fix.
BTW, you should have reported this as a bug via the pgsql-bugs list or
the bug submission form.
Huong> Attached grouping_sets_segv.zip include module to reproduce this
Huong> problem.
A much simpler way to reproduce it is to use one of the builtin types
that isn't sortable (I tend to use xid for testing).
Huong> Not yet fully understand the related commit, but I think it is
Huong> fine to put ERRCODE_FEATURE_NOT_SUPPORTED error from
Huong> preprocess_grouping_sets when all columns in GROUPING SETS are
Huong> unsortable. Is that right?
No, that's definitely wrong. The intent is to be able to generate a
hashed path in this case, it's just the logic that tries to prefer
sorting to hashing when the input arrives already sorted is doing the
wrong thing for unsortable data.
--
Andrew (irc:RhodiumToad)
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