Quickfix reset sequence number at start time but not set ResetSeqNum in Logon message

Question

When the quickfix initiator reconnects at startTime (defined in config) it deletes the files with sequence number, but does not set ResetSeqNumFlag to Y, and the server replies with a Logout message with text "seq msg number to low ..." Is there a way to set ResetSeqNumFlag = Y only for this behavior? I don`t want to reset the sequence on every log-on.

Averill

Answer 1

This appears to be a QuickFIX/J quirk (some might consider it a bug). If ResetOnLogon=N then no ResetSeqNumFlag=Y is sent when the session start time triggers a logon. If ResetOnLogon=Y, the ResetSeqNumFlag=Y is sent on every logon. I believe this is not a big problem in practice because participants in a FIX session typically reset their sequence numbers locally after a session ends (logically ends at the end time, not a connection disconnect).

If you want to slightly modify the source code to implement this behavior, you'd modify the quickfix.Session next() method. You could add a local flag that indicates a session has restarted (per the schedule as determined by checkSessionTime()). Pass that flag to generateLogon() and that method would use it to determine when to send ResetSeqNumFlag=Y regardless of the ResetOnLogon configuration.

Cacophonous

Thank you, I already made it easier: I check seq number for logon message before send it and if seqNum=1 then add ResetSeqNumFlag to this message. – Averill

That sound like a bug in the Acceptor's engine (whoever it might be). After StartTime, both sides should start with and expect 1. ResetSeqNumFlag=Y shouldn't even be necessary; it's implied. The QF/J behavior sounds fine to me. – Cordova

#19517482 any solution ? – Trophoblast

@Averill can you put all the config here. I have the same issue but resolve by adding start date and end date as well – Metacenter

Answer 2

I don`t want to reset the sequence on every log-on.

Then don't do it! Set ResetOnLogon=N.

At StartTime, the session will reset sequence numbers always. If ResetOnLogon=N, then they won't reset again until the next StartTime.

The initiator and acceptor should always have matching ResetOnXXX settings.

Cordova

It is already setted: ResetOnLogon=N. And in next startTime new Logon message send without ResetSeqNumFlag. But server do not reset own sequence and do not expect message seq=1 – Averill

This sounds like the server is acting incorrectly. They shouldn't need to see your flag. They should just reset after StartTime anyway. Are you sure you have their correct session start/end times? – Cordova

Answer 3

What you are asking cannot, should not be done. You start you engine with some config and then you change the config while running. If something goes wrong it will be very difficult to pinpoint what started the issue.

Instead of doing ResetSeqNumFlag = Y try adding ResetOnLogon=Y in your config for the acceptor side(that is if you have control over it) or ResetOnLogout=Y / ResetOnDisconnect=Y in your initiator config file. That would be much easier and changing config while running, is possibly not the best solution.

Your logout(disconnect can happen anytime) will happen anyways at EndTime anyways and should be easier for your application.

Nigrescent