Re: DBD::Informix test failure for lvarchar - bug found!

Dear Mr. Leffler,

When I saw this Tuesday night, I thought... wow. Thanks so much for pursuing this bug report. I will feel more confident in using DBD::Informix, now that you have verified that this bug will not bite us in our present configuration (no lvarchar not null columns).

I'm sure I speak for all DBD::Informix users: Thank you.
--
Mark Abajian


On Jun 12, 2007, at 11:01 PM, Jonathan Leffler wrote:

Finally, after about 30 hours of hair tearing and hard work, I've isolated a
pure ESQL/C version of this bug and demonstrated that it primarily afflicts
32-bit ports of Informix ESQL/C that come with CSDK 2.90 and 2.81 . It does
not afflict most 64-bit ports (though 2.81.FC2 crashed with a core dump, as
did 2.80.UC2), and it does not affect older ports (2.80.UC1 was OK). It did
not reproduce on RHEL 4 running on Linux PPC-64 with CSDK
3.00.FC1(actually, a nightly build prior to that release). Finally,
it only affects
LVARCHAR NOT NULL, and only if the table is not a temporary table. Since I
kept the server constant (IDS 10.00.UC5 running on Solaris 10), the problem
is most likely in ESQL/C rather than IDS itself; if it is perchance in IDS,
it is in the code that recognizes different versions of ESQL/C and somehow
reacts differently.

This bug is now idsdb00139040 in the IBM/Informix CQ database.

Sadly, as yet, I do not have a workaround or fix for this -- that comes
next.
<snip>
To say that the circumstances under which it fails are obscure is to be
excessively polite.

I tried to release an update to DBD::Informix, but the release process goes
through the test suite, and since the test t/t93lvarchar.t was failing, it
was not possible to make the release automatically, so I haven't made the
update. I may decide to cheat and make the release using a 64-bit Perl and
64-bit ESQL/C, like I did with the DBD::Informix 2007.0226 (though that was
released completely unaware of the issue - this one would be released
despite knowing the test fails). The temptation to modify the test (eg to
use a temp table instead of a permanent one) is also quite considerable.

--
Jonathan Leffler <jonathan.leffler@xxxxxxxxx> #include <disclaimer.h>
Guardian of DBD::Informix - v2007.0226 - http://dbi.perl.org
"Blessed are we who can laugh at ourselves, for we shall never cease to be
amused."

.

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