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Date: Mon, 12 Dec 2005 11:37:55 -0800
From: Army <qozinx@sbcglobal.net>
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Subject: Re: Is it possible that DERBY-491 and DERBY-614 are related?
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Bryan Pendleton wrote:
 >> Hi Bryan,  This issues are related to DSS chaining which is something
 >> separate than DERBY-614.
 >> Army made a great  Wiki page on the subject.
 >> http://wiki.apache.org/db-derby/DssProtocolErrors
 >
 >
 > Hi Kathey, thank you very much. I will go read Army's page to learn more.
 >

Hi Bryan,

I was just curious: have you had a chance to look at the Wiki page on 
chaining/continuation?  If so, were able to you tell if the new trace file for 
DERBY-491 (the one that is now hanging with your patch) shows any of the 
symptoms described on the Wiki page?

In particular, I'm wondering if the trace file for the hang is showing any 
*chaining* (as opposed to *continuation*) symptoms.  If so, then it might be the 
case that the change for DERBY-614 has altered chaining in the server, which 
could account for the new hang--and that would require follow-up 
investigation/work since (so far as I know) there weren't any outstanding 
chaining issues prior to the patch for DERBY-614.

If the trace file does _not_ show any signs of chaining issues, then it's 
probably the case that the hang is just a different symptom of the existing 
continuation problem that prompted DERBY-491 in the first place (i.e. no further 
work would be needed...though further investigation would certainly be nice ;)

Note the differentiation between "chaining" and "continuation"; they are 
technically two different things: while there are certainly on-going issues with 
DSS continuation, I think the DSS chaining issues have become more rare (as I 
said, I can't recall any outstanding issues there, thought it is of course 
possible I've just overlooked them).

Also, have you tried running the repros for the other known DSS continuation 
problems with your patch applied?  In particular: DERBY-125, DERBY-170, 
DERBY-492, and DERBY-529?  I'm curious as to whether or not the behavior of 
those tests has changed with the patch for DERBY-614, and if so, whether or not 
that's something that requires closer examination...?

This isn't meant to second-guess your patch for DERBY-614 (I'm so glad someone's 
looking at these protocol errors, as they can be rather tricky--so thanks!), I 
just thought I'd bring up some areas where further/future investigation might be 
necessary/useful.

Army