FastMM5 Freed object class: Unknown

[Babis Michael]

Hello,

After running the server for a couple hours i start to get reports of “Freed object class: Unknown” with FastMM5.

FastMM5 Debug Log: https://www.creationpower.gr/EventLog.txt

Any ideas ?

Thank you

[kimbomadsen]

I can see two of them are related to ElevateDB indexes being freed. kbmMW as such do not do anything with EDB indexes, however what I notice is that you have several debugging layers enabled, MadExcept (which seems to trigger first in all cases), kbmMW’s memory debugging and finally FastMM5’s tracker.

I wonder if MadExcept is “doing something”?

[Babis Michael]

Hello,
I disabled kbmdebugmemory and madexcept so the new log is pure FastMM5:
https://www.creationpower.gr/EventLog2.txt

Thank you

[kimbomadsen]

Thanks.

It looks like that the transport is not disconnected before application shutdown. Can you add a transport.DontListen call and see if the errors disappears?

best regards

Kim/C4D

[Babis Michael]

Hello,
The server isn’t shutting down when the error occurs!
It usually does this when the user is loggin/out.

Thank you

[Babis Michael]

Kim,
Do you have any idea how to debug this in order to find the problem ?

Thank you

[kimbomadsen]

Hi,

Im not aware about any reuse of freed objects in kbmMW. There can be issues on shutdown, if things are not closed in an orderly fashion, but that is not the case you are seeing.

I have many apps that are running 24×7 using kbmMW messaging that do not exhibit any instabillity issues.

I will however, get a license for FastMM5 and check it out more closely.

best regards

Kim/C4D

[Babis Michael]

Hello Kim,
Any news on this ?

[kimbomadsen]

Hi,

I have just run some tests using FastMM5 sending batches of 10001 messages using the WIB in handshake mode (the most complex way of using the WIB because it will attempt retransmission if handshake has not been received for a group of messages within a certain time), on a memory constrained system, sending a million messages from a client node to the server node, and have had no complaints at all from FastMM5.

What I however did discover, is that FastMM5 do not tolerate kbmMW’s memory debugger to be activated at the same time. Then various memory access exceptions will occur in FastMM5 code.

[Babis Michael]

Hello Kim,
Well to me after while it freezes the connections/server.
I’ll try to make out a sample project, where can i send it ?

Thank you

[kimbomadsen]

Hi,
Please send a simple sample (not requiring 3rdparty controls/databases) to kbm@components4developers.com
best regards
Kim/C4D

[Babis Michael]

Hello Kim,
I moved the data from EDB to SQL Express, removed all EDB components, added the necessery MSSQL components to my Server and the problem dissapeared! (No errors or anything for about 12 hours so far)

Can you please check the code of the EDB Sever components that can lead to deadlocks or these kind of FastMM5 reports ?

Thank you

[Babis Michael]

btw, this might help you

https://www.elevatesoft.com/manual?action=viewtopic&id=edb2&product=delphi&version=7&topic=multi_threaded_applications

[kimbomadsen]

Ah… ok… that will be a problem then….
Since each thread will need to instantiate its own database connection when needed, you should move the connection pool onto the query service instead.

It will defeat the connection pool mechanism, but will ensure that the connection is living in the thread space of the query service instance.

[Babis Michael]

I’ve modified kbmMWEDB to create a new session with lock and it seems to be working! As soon as i finish the testing i’ll send you the fix!

Thank you

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