[ovirt-users] [ovirt-devel] ovirt-engine-sdk-python too slow

[Juan Hernández]

On 11/24/2015 02:49 PM, John Hunter wrote:
> 
> 
> On Tue, Nov 24, 2015 at 9:15 PM, Juan Hernández <jhernand at redhat.com
> <mailto:jhernand at redhat.com>> wrote:
> 
>     On 11/24/2015 01:40 PM, John Hunter wrote:
>     > Hi,
>     >
>     > On Tue, Nov 24, 2015 at 5:18 PM, Oved Ourfali <oourfali at redhat.com <mailto:oourfali at redhat.com>
>     > <mailto:oourfali at redhat.com <mailto:oourfali at redhat.com>>> wrote:
>     >
>     >     Hi
>     >
>     >     I discussed it with Juan (cc-ed).
>     >
>     >     There used to be a bug in the JDBC authenticion extension that
>     >     artificially delayed RESTAPI responses by 5 seconds:
>     >
>     >       brute force prevention login delay should not be applied to successful
>     >     login requests
>     >       https://bugzilla.redhat.com/1255814
>     >
>     >     That matches the description of the issue, but in theory it has been
>     >     fixed. I would suggest him to check that he is using the right version
>     >     of the extension.
>     >
>     > I did not use the extension ovirt-engine-extension-aaa-jdbc, and I don't
>     > think this bug matches my problem, because even there is only one line
>     > in the python script, it still cost like 3 seconds, I don't think this is a
>     > reasonable time as when I import other package, it cost almost no time.
>     >
>     > Can you explain why this import line costs so much time?
>     >
> 
>     If you are using 3.6 then you are using ovirt-engine-extension-aaa-jdbc,
>     as it is enabled by default, but looks like it isn't related to your
>     problem.
> 
>     That line takes a long time to execute because it has to process two
>     large Python modules: the "params" module that contains a class per each
>     type used by the API (393 classes) and the "brokers" module that
>     contains a class per each resource used by the API (358 classes). That
>     makes a total of 751 classes. In my environment it takes 0.9 seconds,
>     approx. You may want to use the python profile in your environment and
>     share the results:
> 
>     $ cat > profile.py <<.
>     import cProfile
>     cProfile.run("from ovirtsdk.api import API")
>     .
> 
>     $ python profile.py
> 
>     I won't be surprised to see this taking those 3 seconds in a slower
>     environment.
> 
>     But even if this takes those 3 seconds it shouldn't be a big problem,
>     because you shouldn't be running that "from ... import ..." line
>     frequently. Your program should do this once only, when it starts.
> 
> Assume that I have two functions to implement, one is to list all the
> vms belong
> to the user, and the other is to retrieve one vm's virt-viewer
> connection file, as 
> far as I can see, I have to write two python scripts and import the
> ovirtsdk.api in both
> scripts, each script has to take the 3 seconds :(
> 
> How can I run the "from ... import ..." just once ?
>  

I don't know what technology or tools are you using to write that
program, but if you are using Python then you don't need to import it twice.

If for whatever the reason you decide to call external python scripts
from another program then you will have to pay the price of the startup
of the Python SDK. If that is unacceptable because of performance then
you should look for a different way to access the RESTAPI, like sending
XML or JSON directly, or using the Java SDK, or rbovirt, it all depends
on the technology that you are using for your application.

> 
>     >
>     >     In addition we also know that retrieving large lists of objects with the
>     >     SDK is slow:
>     >
>     >        [RFE][performance] - generate large scale list running to slow.
>     >        https://bugzilla.redhat.com/1221238
>     >
>     >     We don't have a solution for that yet.
>     >
>     >     CC-ing Juan in case you have additional questions.
>     >
>     >
>     >     On Mon, Nov 23, 2015 at 11:27 AM, John Hunter <zhjwpku at gmail.com <mailto:zhjwpku at gmail.com>
>     >     <mailto:zhjwpku at gmail.com <mailto:zhjwpku at gmail.com>>> wrote:
>     >
>     >         Hi guys,
>     >
>     >         I am using the ovirt-engine-sdk-python to communicate with the
>     >         ovirt-engine,
>     >         I am ok to list the vms but the processing time is too long,
>     >         like 4.5 seconds,
>     >         and this line:
>     >             from ovirtsdk.api import API
>     >         take almost 3 seconds.
>     >
>     >         This seems a little bit longer than I expected it to be, so I am
>     >         asking is there
>     >         a quicker way to communicate with the ovirt-engine?
>     >
> 

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