http://ayende.comAyende @ RahienCopyright (C) Ayende Rahien 2004 - 2021 (c) 202660As I said, we run into this error in QA. Once I had the stack trace, and the error, it was really obvious what was wrong http://ayende.com/4035/challenge-find-the-bug#comment38http://ayende.com/4035/challenge-find-the-bug#comment38Thu, 28 May 2009 00:28:55 GMTSilly question: why is there a commit limit? http://ayende.com/4035/challenge-find-the-bug#comment37http://ayende.com/4035/challenge-find-the-bug#comment37Thu, 28 May 2009 00:07:53 GMTWow... gloubidou I am impress. Oren, how did you uncover the bug? If the application throw an exception somewhere then it's probably not that hard to trace down the culprit. Did you catch it through stress testing? http://ayende.com/4035/challenge-find-the-bug#comment36http://ayende.com/4035/challenge-find-the-bug#comment36Wed, 27 May 2009 22:51:56 GMTgloubidou, TADA! You got it! When you hit it exactly right, you may get a LOT of expired values. Those expired values can be big enough to hit the commit limit, and cause an error! So I _was_ stupid, I thought so! :-) http://ayende.com/4035/challenge-find-the-bug#comment35http://ayende.com/4035/challenge-find-the-bug#comment35Wed, 27 May 2009 21:13:17 GMTCommit size will become huge in this case... Since you say that it is about code that isn't there, all I am able to come with is fixing a maximum of expired values to be processed in the loop and process the remaining later. That's similar to ORA-01555 snapshot too old! http://ayende.com/4035/challenge-find-the-bug#comment34http://ayende.com/4035/challenge-find-the-bug#comment34Wed, 27 May 2009 21:11:22 GMTNeal, No, that is not that. And you don't need to understand anything about the API to see the problem. The problem is that until you see the problem, you don't know what it is. I am actually encouraged that no one managed to find it. It means that I am not that stupid http://ayende.com/4035/challenge-find-the-bug#comment33http://ayende.com/4035/challenge-find-the-bug#comment33Wed, 27 May 2009 21:07:23 GMTYou get the version but do not check it has expired? TBH I am guessing based on what I would expect to see rather than understanding the code / api that this is using but it seems like the most logical thing. http://ayende.com/4035/challenge-find-the-bug#comment32http://ayende.com/4035/challenge-find-the-bug#comment32Wed, 27 May 2009 20:47:13 GMTEveryone, Notice what I said, what is the code that IS NOT THERE?! http://ayende.com/4035/challenge-find-the-bug#comment31http://ayende.com/4035/challenge-find-the-bug#comment31Wed, 27 May 2009 20:18:33 GMTTwo Api.JetDelete calls? http://ayende.com/4035/challenge-find-the-bug#comment30http://ayende.com/4035/challenge-find-the-bug#comment30Wed, 27 May 2009 20:14:09 GMTSander, keys is the variable holding the table name, not a collection. It is instruction to delete the current row. http://ayende.com/4035/challenge-find-the-bug#comment29http://ayende.com/4035/challenge-find-the-bug#comment29Wed, 27 May 2009 18:59:10 GMTThe call to Api.JetDelete should probably be called with session and key, not session and keyS (deleting everything)? http://ayende.com/4035/challenge-find-the-bug#comment28http://ayende.com/4035/challenge-find-the-bug#comment28Wed, 27 May 2009 18:33:34 GMTMichael, Huh? What timer? There isn't any external code involved that affect the bug in this function http://ayende.com/4035/challenge-find-the-bug#comment27http://ayende.com/4035/challenge-find-the-bug#comment27Wed, 27 May 2009 17:05:06 GMTThat is a user defined value. In the system that we are talking abut, 24 hours http://ayende.com/4035/challenge-find-the-bug#comment26http://ayende.com/4035/challenge-find-the-bug#comment26Wed, 27 May 2009 17:04:10 GMTYou're calling the function on a fixed timer and it's being executed again, before the previous execution has finished. Considering it results in a crash, it's probably stacking a good number of times. http://ayende.com/4035/challenge-find-the-bug#comment25http://ayende.com/4035/challenge-find-the-bug#comment25Wed, 27 May 2009 16:53:26 GMTHow often do values expire? http://ayende.com/4035/challenge-find-the-bug#comment24http://ayende.com/4035/challenge-find-the-bug#comment24Wed, 27 May 2009 16:38:37 GMTDuvallBuck, No, that is not the behavior we have http://ayende.com/4035/challenge-find-the-bug#comment23http://ayende.com/4035/challenge-find-the-bug#comment23Wed, 27 May 2009 15:24:00 GMTgloubidou, Tada, you are _very_ close. aaron, No, you don't. http://ayende.com/4035/challenge-find-the-bug#comment22http://ayende.com/4035/challenge-find-the-bug#comment22Wed, 27 May 2009 15:22:09 GMTIf the Api.RetrieveColumnAsString gets the first one then the Api.TryMovePrevious would never go to the rest but stop when the first one is deleted. http://ayende.com/4035/challenge-find-the-bug#comment21http://ayende.com/4035/challenge-find-the-bug#comment21Wed, 27 May 2009 14:23:17 GMTdo we need to know the contract of the jet api to find the problem? http://ayende.com/4035/challenge-find-the-bug#comment20http://ayende.com/4035/challenge-find-the-bug#comment20Wed, 27 May 2009 13:23:12 GMTI guess that you are trying to clean expired values (stuff we don't care about anymore).. thus having a big result set would pose a problem... am I right? http://ayende.com/4035/challenge-find-the-bug#comment19http://ayende.com/4035/challenge-find-the-bug#comment19Wed, 27 May 2009 12:58:37 GMTGerke, It is marking that for deletion in the end of the current transaction, TryMovePrevious is not the issue. The loop will terminate at the expected time. http://ayende.com/4035/challenge-find-the-bug#comment18http://ayende.com/4035/challenge-find-the-bug#comment18Wed, 27 May 2009 12:42:59 GMTStephen, No stack overflow, no, and not an infinite loop, but you should concentrate on the loop http://ayende.com/4035/challenge-find-the-bug#comment17http://ayende.com/4035/challenge-find-the-bug#comment17Wed, 27 May 2009 12:41:58 GMTAh, true ;) (btw ayende, having problems submitting comments from ie7/8- not sure if its just me, hitting submit doesn't do anything it just sits there). http://ayende.com/4035/challenge-find-the-bug#comment16http://ayende.com/4035/challenge-find-the-bug#comment16Wed, 27 May 2009 12:25:50 GMTStephen, That would hang, not crash... http://ayende.com/4035/challenge-find-the-bug#comment15http://ayende.com/4035/challenge-find-the-bug#comment15Wed, 27 May 2009 11:48:38 GMTWhat happens to the table cursor after Api.JetDelete()? And does Api.JetDelete() immediately remove the table row or only mark it as deleted? Otherwise scenario could be: - Api.JetDelete moves cursor forward - Api.TryMovePrevious moves cursor backwards (to same row) => infinite loop http://ayende.com/4035/challenge-find-the-bug#comment14http://ayende.com/4035/challenge-find-the-bug#comment14Wed, 27 May 2009 11:17:35 GMTI take it the crash is a stack overflow from an infinite loop and that you are either missing a breaking condition or not doing something that would should effect the 'position'.. Basically no idea, is this something that will probably only make sense when illustrated and explained? http://ayende.com/4035/challenge-find-the-bug#comment13http://ayende.com/4035/challenge-find-the-bug#comment13Wed, 27 May 2009 11:01:15 GMTmeo, No, that is not it. It works just fine. http://ayende.com/4035/challenge-find-the-bug#comment12http://ayende.com/4035/challenge-find-the-bug#comment12Wed, 27 May 2009 10:52:38 GMTMaybe "v => Api.JetDelete(session, data)" can't be run thru delegate for some reason? http://ayende.com/4035/challenge-find-the-bug#comment11http://ayende.com/4035/challenge-find-the-bug#comment11Wed, 27 May 2009 10:13:11 GMTAlexander, No, that is not it http://ayende.com/4035/challenge-find-the-bug#comment10http://ayende.com/4035/challenge-find-the-bug#comment10Wed, 27 May 2009 09:55:14 GMTmaybe issue is related with closure of the session and data variables here: v=>Api.JetDelete(session, data) http://ayende.com/4035/challenge-find-the-bug#comment9http://ayende.com/4035/challenge-find-the-bug#comment9Wed, 27 May 2009 09:53:25 GMT