[omniORB] 3 questions about CORBA, IIOP, and omniORB

[Thomas Zumbiehl]

Hi,

I can sometimes see some strange behavior in my server, compiled with omniORB 4.0.7 :
I send 50 identical requests to my server, sometimes 2 fail.
When it fails, I can see these (abnormal, to my application point of view) omniORB traces :
2008/12/17 11-14-32 : omniORB: (38)
4749 4f50 0102 0100 a400 0000 1306 0000 GIOP............
0300 0000 0000 0000 1700 0000 ff62 6964 .............bid
6972 706f 61fe 3ccc 4849 0100 1bb9 0000 irpoa.<.HI......
0000 a750 1000 0000 6765 7453 656c 6563 ...P....getSelec
7452 6573 756c 7400 0000 0000 0000 0000 tResult.........
1200 0000 4167 656e 7449 436c 6553 6572 ....AgentICleSer
7669 6365 7300 0001 0100 0000 1b00 0000 vices...........
4943 6c65 4e61 6d65 2c53 6572 7669 6365 ICleName,Service
5479 7065 2c4c 6162 656c 0039 1400 0000 Type,Label.9....
5365 7276 6963 654e 616d 653d 5243 3832 ServiceName=RC82
5048 4100 0100 0000 0031 3839 0000 0000 PHA......189....
2008/12/17 11-14-32 : omniORB: (38) Dispatching remote call 'getSelectResult' to: root/bidirpoa<167> (active)
...
2008/12/17 11-14-32 : omniORB: (38) omniRemoteIdentity deleted.
2008/12/17 11-14-32 : omniORB: (38) ObjRef(IDL:corbacom/LogServiceInterface:1.0) -- deleted.
...
2008/12/17 11-14-32 : omniORB: (38) sendChunk: to giop:tcp:10.151.35.219:41645 28 bytes
2008/12/17 11-14-32 : omniORB: (38)
4749 4f50 0102 0101 1000 0000 1306 0000 GIOP............
0000 0000 0000 0000 0000 0000 ............
That bring my global system wrong.


So, first question : I there any kind of way omniORB could delete an omniRemoteIdentity where it should not, or is it possible that it is displaying wrong information ?
The fact is that the same sequence occurs at both one of the two failures. And omniORB says, two times, that the omniRemoteIdentity is deleted, while there should be only one holded (set earlier in the application) ?

Second question : What is the meaning of the 28 bytes chunk sent ? It seems to be understood as a reply to the getSelectResult() request...

Third question : My server needs to hold interfaces for a while, but those need to be deactivated while they are not used (I use a close() request to tell an interface that it can be destroyed). How should I handle the servant activation/deactivation ?
For now, I use the POA's activate_object() and deactivate_object() methods, but I am now thinking I can be wrong.
For instance, I know that calling the _this() method on a servant will automaticaly activate it, but how can I deactivate it ?

I know that I ask many questions, and that some answer can be trivial, but I am really lost in that "funny" problem.

Cheers,
Thomas

Thomas Zumbiehl
Chef de Projet D?veloppement
BV Associates
http://www.bvassociates.fr <http://www.bvassociates.fr/>

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[Jon Biggar]

Post by Thomas Zumbiehl
Hi,

[snip]

Post by Thomas Zumbiehl
So, first question : I there any kind of way omniORB could delete an
omniRemoteIdentity where it should not, or is it possible that it is
displaying wrong information ?
The fact is that the same sequence occurs at both one of the two
failures. And omniORB says, two times, that the omniRemoteIdentity is
deleted, while there should be only one holded (set earlier in the
application) ?

My best guess is that you have a reference count management error on an
object reference that you want to use.

Post by Thomas Zumbiehl
Second question : What is the meaning of the 28 bytes chunk sent ? It
seems to be understood as a reply to the getSelectResult() request...

Yes.

Post by Thomas Zumbiehl
Third question : My server needs to hold interfaces for a while, but
those need to be deactivated while they are not used (I use a close()
request to tell an interface that it can be destroyed). How should I
handle the servant activation/deactivation ?
For now, I use the POA's activate_object() and deactivate_object()
methods, but I am now thinking I can be wrong.
For instance, I know that calling the _this() method on a servant will
automaticaly activate it, but how can I deactivate it ?

I'd recommend reading "Advanced CORBA Programming with C++" by Henning
and Vinoski. They have an extensive section about server design and
policy selection that answers your questions.

[Michael]

About your last question: Depending on your requirements, the easiest
way to go is to use persistent objects and a default servant (if you're
concerned about memory usage). There a many different ways of
accomplishing what you want in CORBA, so you should try to chose the
easiest/least error prone. Without more details about your
implementation requirements it's hard to give you more discreet advice.

Post by Thomas Zumbiehl
Hi,
I send 50 identical requests to my server, sometimes 2 fail.
2008/12/17 11-14-32 : omniORB: (38)
4749 4f50 0102 0100 a400 0000 1306 0000 GIOP............
0300 0000 0000 0000 1700 0000 ff62 6964 .............bid
6972 706f 61fe 3ccc 4849 0100 1bb9 0000 irpoa.<.HI......
0000 a750 1000 0000 6765 7453 656c 6563 ...P....getSelec
7452 6573 756c 7400 0000 0000 0000 0000 tResult.........
1200 0000 4167 656e 7449 436c 6553 6572 ....AgentICleSer
7669 6365 7300 0001 0100 0000 1b00 0000 vices...........
4943 6c65 4e61 6d65 2c53 6572 7669 6365 ICleName,Service
5479 7065 2c4c 6162 656c 0039 1400 0000 Type,Label.9....
5365 7276 6963 654e 616d 653d 5243 3832 ServiceName=RC82
5048 4100 0100 0000 0031 3839 0000 0000 PHA......189....
2008/12/17 11-14-32 : omniORB: (38) Dispatching remote call 'getSelectResult' to: root/bidirpoa<167> (active)
...
2008/12/17 11-14-32 : omniORB: (38) omniRemoteIdentity deleted.
2008/12/17 11-14-32 : omniORB: (38) ObjRef(IDL:corbacom/LogServiceInterface:1.0) -- deleted.
...
2008/12/17 11-14-32 : omniORB: (38) sendChunk: to giop:tcp:10.151.35.219:41645 28 bytes
2008/12/17 11-14-32 : omniORB: (38)
4749 4f50 0102 0101 1000 0000 1306 0000 GIOP............
0000 0000 0000 0000 0000 0000 ............
That bring my global system wrong.
So, first question : I there any kind of way omniORB could delete an omniRemoteIdentity where it should not, or is it possible that it is displaying wrong information ?
The fact is that the same sequence occurs at both one of the two failures. And omniORB says, two times, that the omniRemoteIdentity is deleted, while there should be only one holded (set earlier in the application) ?
Second question : What is the meaning of the 28 bytes chunk sent ? It seems to be understood as a reply to the getSelectResult() request...
Third question : My server needs to hold interfaces for a while, but those need to be deactivated while they are not used (I use a close() request to tell an interface that it can be destroyed). How should I handle the servant activation/deactivation ?
For now, I use the POA's activate_object() and deactivate_object() methods, but I am now thinking I can be wrong.
For instance, I know that calling the _this() method on a servant will automaticaly activate it, but how can I deactivate it ?
I know that I ask many questions, and that some answer can be trivial, but I am really lost in that "funny" problem.
Cheers,
Thomas
Thomas Zumbiehl
Chef de Projet D?veloppement
BV Associates
http://www.bvassociates.fr <http://www.bvassociates.fr/>
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[Duncan Grisby]

Post by Thomas Zumbiehl
I can sometimes see some strange behavior in my server, compiled with omniORB
I send 50 identical requests to my server, sometimes 2 fail.

What exactly do you see at the application level when they fail?

Post by Thomas Zumbiehl
When it fails, I can see these (abnormal, to my application point of view)
2008/12/17 11-14-32 : omniORB: (38)
4749 4f50 0102 0100 a400 0000 1306 0000 GIOP............
0300 0000 0000 0000 1700 0000 ff62 6964 .............bid
6972 706f 61fe 3ccc 4849 0100 1bb9 0000 irpoa.<.HI......
0000 a750 1000 0000 6765 7453 656c 6563 ...P....getSelec
7452 6573 756c 7400 0000 0000 0000 0000 tResult.........
1200 0000 4167 656e 7449 436c 6553 6572 ....AgentICleSer
7669 6365 7300 0001 0100 0000 1b00 0000 vices...........
4943 6c65 4e61 6d65 2c53 6572 7669 6365 ICleName,Service
5479 7065 2c4c 6162 656c 0039 1400 0000 Type,Label.9....
5365 7276 6963 654e 616d 653d 5243 3832 ServiceName=RC82
5048 4100 0100 0000 0031 3839 0000 0000 PHA......189....
2008/12/17 11-14-32 : omniORB: (38) Dispatching remote call 'getSelectResult'
to: root/bidirpoa<167> (active)

This is a normal incoming request call.

Post by Thomas Zumbiehl
...
2008/12/17 11-14-32 : omniORB: (38) omniRemoteIdentity deleted.
2008/12/17 11-14-32 : omniORB: (38) ObjRef(IDL:corbacom/
LogServiceInterface:1.0) -- deleted.

This means that an object reference was deleted. Whether that's right or
wrong depends on what your application is doing with object references.
The omniRemoteIdentity is an internal part of the object reference that
has been deleted.

Post by Thomas Zumbiehl
...
2008/12/17 11-14-32 : omniORB: (38) sendChunk: to giop:tcp:10.151.35.219:41645
28 bytes
2008/12/17 11-14-32 : omniORB: (38)
4749 4f50 0102 0101 1000 0000 1306 0000 GIOP............
0000 0000 0000 0000 0000 0000 ............

That's a reply message. It looks normal.

Post by Thomas Zumbiehl
That bring my global system wrong.

In what way? There's nothing unusual looking about those traces.

Post by Thomas Zumbiehl
So, first question : I there any kind of way omniORB could delete an
omniRemoteIdentity where it should not, or is it possible that it is
displaying wrong information ?
The fact is that the same sequence occurs at both one of the two
failures. And omniORB says, two times, that the omniRemoteIdentity is
deleted, while there should be only one holded (set earlier in the
application) ?

The omniRemoteIdentity is deleted when the object reference it is inside
is deleted. Only you can tell us if you're expecting an object reference
to be deleted at that stage. If you're not expecting one to be deleted,
you have your reference counting wrong.

Post by Thomas Zumbiehl
Second question : What is the meaning of the 28 bytes chunk sent ? It seems to
be understood as a reply to the getSelectResult() request...

It is indeed a reply to the getSelectResult call.

Post by Thomas Zumbiehl
Third question : My server needs to hold interfaces for a while

"Interfaces" are not things you can hold. You probably mean servants
that incarnate particular objects, which have particular interfaces.

Post by Thomas Zumbiehl
, but those need to be deactivated while they are not used (I use a
close() request to tell an interface that it can be destroyed). How
should I handle the servant activation/deactivation ?
For now, I use the POA's activate_object() and deactivate_object() methods,
but I am now thinking I can be wrong.

Those are the right methods to use.

You should read "Advanced CORBA Programming with C++" to learn all about
the correct terminology and object lifecycles and so on.

Cheers,

Duncan.