I've got a customer who's been running an older version of our software for several years that is all of a sudden getting 506 errors.  I'm well aware of the cause of 506 errors from the client side of things in a C/S setup, such as timers and/or threads attempting to access the same session while it's already doing something.

What I'm wondering is if there is anything from the server side that could cause a 506 error on the client side, such as a long running process on the server, a lost connection, or a DB server engine restart.  After the 506 error, they are seeing an 1101 indicating a timeout while receiving stream.  After the errors occur, they have to reboot the server system to get everything working again.  

For reference, it's EDB 2.14b5 on both the client and server side with the server engine running on a Server 2012 R2 virtual machine.

The odd part is that the issues almost always occur around the same time of day, about 4am.  There is no anti-virus or anti-malware products on the VM, we've disabled the server backups temporarily, made sure that there wasn't any scheduled tasks, and there are no jobs being run from the DB server engine.

Not much to go on, but hoping that this jogs someone's memory of something similar that I can look into, or that this might be caused by something corrected in a later build of the database engine?

Terry Swiers
Millennium Software, Inc.

Terry,

<< I've got a customer who's been running an older version of our software for several years that is all of a sudden getting 506 errors.  I'm well aware of the cause of 506 errors from the client side of things in a C/S setup, such as timers and/or threads attempting to access the same session while it's already doing something.

What I'm wondering is if there is anything from the server side that could cause a 506 error on the client side, such as a long running process on the server, a lost connection, or a DB server engine restart.  After the 506 error, they are seeing an 1101 indicating a timeout while receiving stream.  After the errors occur, they have to reboot the server system to get everything working again. >>

Why do they have to reboot the server ?  This is a client-side issue.

Tim Young
Elevate Software
www.elevatesoft.com

> Why do they have to reboot the server ?  This is a client-side issue.

That's just been their solution to the problem because it forces the users to restart the client application as well.

But your response that 506 is client-side only does answer the question.

Terry,

<< That's just been their solution to the problem because it forces the users to restart the client application as well.

But your response that 506 is client-side only does answer the question. >>

Not necessarily.  You can get a session lock on the server also, but such a situation is rare because it has to occur in a situation whereby:

1) The client's remote session times out while waiting for a very long request to finish executing on the EDB Server, and the client's remote session disconnects from the EDB Server.
2) The EDB Server is still busy servicing the very long request.
3) The client tries to reconnect the remote session by trying another operation - boom, you've got a session lock error because the EDB Server still has the session locked on the server while it's servicing the long request.

Tim Young
Elevate Software
www.elevatesoft.com

> Why do they have to reboot the server ?  

The 506 error was being caused by a threading issue (which we knew about and had already corrected in a later version of our software) in the middle of a database transaction.  The customer was assuming that the server engine was hanging, but in reality it was just waiting for the client application to either commit the transaction or roll it back.  The reason for the reboot was just impatience and not completely understanding the actual problem.