No.  No further to resolving this issue.  It maybe a network issue that is causing a serious problem for Firebird 1.56 but that is only a guess.

Even more bizzare - introducing a VPN connection into the network with a client app connected over the VPN and the freezes don't happen (though only 3 days clear running so far).

Paul

 

Exactly the same problem here. I'm on a different platform (Debian
stable x64, Delphi app with BDE, etc), so it's most probably not a
platform/toolkit issue. Did you solve the problem?

EB

On 15/05/14 03:12, Paul Read pr@... [firebird-support] wrote:
>
>
> Summary:
> All clients freeze until FBServer is restarted
>
> Background:
> For the past 6 months plus, a couple of our customers have been
> experiencing our client application locking up for all users. We have
> spent considerable resources trying to understand the issue but have
> made little progress and are now reaching out to the Firebird community
> for suggestions on how to overcome or at least minimize occurrence of
> this issue
>
> Typical database installation:
> * SuperServer 1.5.6.5026 SuperServer running as a service with FBGuardian
> * Borland C++ 2007 VCL with IB Objects (8/25/2007 Sub-Release 4.8 Build
> 7) based client applications
> * Client application is basically single threaded event driven
> * Single FB database on server only
> * Typically a dedicated MS-Windows based machine for the database server
> * Each client has two connections to DB that are open for the life time
> of the app (1 for data, 1 for events)
> * Typically sub 3GB fdb file
> * Typically 3-20 clients per database installation
>
> 70+ installations across the globe work fine but 2 are suffering:
> * all connected clients freezing concurrently (within a minute of each
> other)
> * sometimes 3 or more times a day
> * sometimes can go 5-10 days without an issue then multiple freezes
> * clients remain locked up until FBServer is restarted at which point
> they suddenly spring into life reporting the connection is lost
> * Worse case the freeze can happen 10 mins or so after restarting the
> FBServer
> * restarting the server machine does not help the issue i.e. just as
> likely to happen as just restarting FBServer via Control Panel
> * FBServer at freeze point does not show high CPU or memory consumption
> in task manager
> * Waiting 10 mins and still the clients do not recover
> * Nothing unusual in MS-Windows event table
> * Nothing unusual in Firebird logs
> * No Anti-virus running on servers
> * No firewall running on servers
> * Full firewall exceptions given for client applications
> * Bizarrely seems to be far worse on Thursday and Fridays for one of the
> installations (no crash pattern yet noted at the other installation)
> * other client applications connected to the same database and using
> same build technology but with different exe names do not appear to be
> impacted (though they are far less intensive and so this may be
> misinformation)
> * Client application running directly on the server also freezes
> * Both these installations are running MS-Windows 7 as their servers
> (but so are working installations)
> * Seems to be event related, as a typical madExcept call stack at the
> point of freeze shows 'isc_que_events':
>
> 778af8ca +00e ntdll.dll NtWaitForSingleObject
> 75472f7b +05b ws2_32.dll WahReferenceContextByHandle
> 75476a25 +09c ws2_32.dll select
> 064b6d59 +069 fbclient.dll isc_que_events
> 0064e92e +06e nCall.exe Ib_components TIB_Component.CheckSession
> 00773157 +06f nCall.exe Ib_events TIB_Events.API_QueueEvents
> 007729d1 +09d nCall.exe Ib_events TIB_Events.RegisterEvents
> 0040ebf4 +7ec nCall.exe TSubscriber.cpp 287 +68 TSubscriberIBO.SetEvents
> 0040d40b +2eb nCall.exe TSubscriber.cpp 67 +9 TSubscriber.AddEvent
> 004bf350 +fa8 nCall.exe TdmMain.cpp 400 +170 TdmMain.Connect
>
> We have tried:
> * Backup and restore has no benefit with freezes experienced within a
> few hours of a backup and restore
> * Daily restart of the database server - no effect
> * The freeze is not related to performing a backup
> * The freeze is not related to performing an intense job
> * Clients on static and dynamic IPs - no effect
> * Firewall exceptions have been verified at both installations with
> program exceptions for the clients
> * RemoteAuxPort values of 0, 3051, 40000 tried with no noticeable benefit
> * We've tried registering for more events
> * We've tried ensuring an event is generated every minute (in an attempt
> to keep the event port open in case it is being closed through lack of use)
> * 3rd party network experts tell us there are no networking working
> issues being experienced by other applications
> * Users have suggested that the client application normally slows down
> before the freezing (not verified)
> * FBClient.dlls 1.52 and 1.56 (including ensuring all clients are using
> same version)
>
> Having read many postings regarding similar issues, only these two
> appear useful but don't indicate any real solutions or if the issue has
> been resolved in a later version of Firebird.
> *
> https://groups.yahoo.com/neo/groups/firebird-support/conversations/messages/75364
> *
> https://groups.yahoo.com/neo/groups/firebird-support/conversations/messages/75366
>
> Suggestions on what to try next sought!
> Paul
>
>