From: | David Hartwig <daybee(at)bellatlantic(dot)net> |
---|---|
To: | hackers <pgsql-hackers(at)postgresql(dot)org> |
Subject: | 6.4 Aggregate Bug |
Date: | 1998-08-01 09:19:43 |
Message-ID: | 35C2DDAF.4E174FC0@bellatlantic.net |
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Lists: | pgsql-hackers |
While testing my 6.4 patch to allow functions/expressions to be
specified in the ORDER/GROUP BY clause (and not in the target list) I
came across a nasty little bug. A segmentation fault gets thrown
somewhere in replace_agg_clause() when using aggregates, in combination
with a function or expression. (I am still tracking down the
offending lines of code. Sorry, the Linux/GCC environment is still new
to me.)
I backed out my patch, and discovered the bug was still present. The
bug does not exist in version 6.3.2. Here is an example:
-- This crashes the backend
select upper(a) as x, count(k) from t group by x;
-- This works fine
select upper(a) as x, count(a) from t group by x;
Notice how in the first query, (the one that does not work) upper() has
a different argument than count(). And in the second query (the one
that works) upper() has the same argument as count(). When using
count(*) it will always fail.
This is the the pattern that I have observed. If the arguments in the
aggregate and non-aggregate functions are the same, it runs; if the
arguments in the aggregate and non-aggregate functions are different, it
crashes.
I have attached a test script for anyone able to help with (or verify)
this problem.
Attachment | Content-Type | Size |
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t.sql | text/plain | 919 bytes |
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