server-side memory leaks using taurus widgets

[Roberto Borghes]

Hi dancers,
here at Elettra we've experienced a strange situation on a specific
beamline: some device servers showed a memory leak if used in
combination with python panels.
We spent a lot of time on the topic but fortunately we've discovered
that the memory leak appears only if we use the fully qualified domain
name for the Tango attributes.
An important step was the analysis of the blackbox of the device
servers: there were periodic calls of the function
get_attribute_config_3() (multiple connections from the client?)

We are using:
- tango 8.1.2.c on CentOS6 x64 server side
- tango 8.1.2.c on CentOS7 x64, PyTango 816 client side .

Did anyone experience a similar situation?

Thank you all in advance,
Roberto

[Andy Gotz]

Hi Roberto,

this sounds like a bug. Can you make a bug report on the bug tracker?
Can you reproduce the bug with a simple python program i.e. no graphics?

Andy

[Roberto Borghes]

Hi Andy,
I don't know if it's a bug but I've done some tests and I've discovered
that the problem may occur when there is an ambiguous resolving of the
TANGO_HOST name.
In our case we had the need to change the hostname of the machine
hosting the Tango DB.
On a client workstation the TANGO_HOST variable has not been updated but
the system worked the same because the DNS resolves the new and the old
name.
In this case, using TangoTest and taurusform as client, we can reproduce
a memory leak on TangoTest due to the different TANGO_HOST variable.
Monitoring the blackbox of TangoTest with Jive, I've noticed that the
taurus panel performs a periodic call of the function
get_attribute_config_3() instead of doing it just at startup.

Ciao,
Roberto

On 29/06/2016 17:07, Andy Gotz wrote:
> Hi Roberto,
>
> this sounds like a bug. Can you make a bug report on the bug tracker?
> Can you reproduce the bug with a simple python program i.e. no graphics?
>
> Andy
>
> On 29/06/2016 16:43, Roberto Borghes wrote:

[Roberto Borghes]

Hi,
a small upgrade about a test on the topic.
Server side the TangoTest device is running with TANGO_HOST set to
mydbhost.esce.elettra.trieste.it:10000;
Client side TANGO_HOST is not set;

The memory leak server side appears taurusform is launched in the
following modes :
- taurusform tango://mydbhost.esce:10000/sys/tg_test/1
- taurusform tango://172.19.230.7:10000/sys/tg_test/1

There are no problems if taurusform is launched in the following modes :
- taurusform tango://mydbhost:10000/sys/tg_test/1
- taurusform
tango://mydbhost.esce.elettra.trieste.it:10000/sys/tg_test/1

Ciao,
Roberto

On 01/07/2016 15:54, Roberto Borghes wrote:
> Hi Andy,
> I don't know if it's a bug but I've done some tests and I've
> discovered that the problem may occur when there is an ambiguous
> resolving of the TANGO_HOST name.
> In our case we had the need to change the hostname of the machine
> hosting the Tango DB.
> On a client workstation the TANGO_HOST variable has not been updated
> but the system worked the same because the DNS resolves the new and
> the old name.
> In this case, using TangoTest and taurusform as client, we can
> reproduce a memory leak on TangoTest due to the different TANGO_HOST
> variable.
> Monitoring the blackbox of TangoTest with Jive, I've noticed that the
> taurus panel performs a periodic call of the function
> get_attribute_config_3() instead of doing it just at startup.
>
> Ciao,
> Roberto
>
>
>
> On 29/06/2016 17:07, Andy Gotz wrote:
>> Hi Roberto,
>>
>> this sounds like a bug. Can you make a bug report on the bug tracker?
>> Can you reproduce the bug with a simple python program i.e. no graphics?
>>
>> Andy
>>
>> On 29/06/2016 16:43, Roberto Borghes wrote: