[ovirt-users] Delay difference between queries (Python vs REST)

[Nicolas Ecarnot]

Le 17/01/2017 à 16:26, Juan Hernández a écrit :
> On 01/17/2017 03:56 PM, Nicolas Ecarnot wrote:
>> Hello,
>>
>> On a 3.6.5 DC, I'm trying to figure out how many VMs there are, using
>> two methods :
>>
>> _*Python SDK :*_
>>
>> *from ovirtsdk.xml import params
>> from ovirtsdk.api import API
>> api = API(url='https://engine.fqdn/ovirt-engine/api',
>> username='admin at internal', password='xxx', insecure=True)
>> print len(api.vms.list())*
>>
>> time ./getMvm.py
>> 62
>>
>> real    0m23.016s
>> user    0m22.288s
>> sys    0m0.054s
>>
>>
>> _*REST :*_
>>
>> *time curl -H "Version: 3" -H "Prefer: persistent-auth" -H "Filter:
>> false" -H "Accept: application/xml" -H "Content-Type: application/xml"
>> -k -u 'admin at internal:xxx' https://***engine.fqdn*/ovirt-engine/api/vms*
>>
>> (Then grep or anything that would get the values from the xml returned.)
>>
>> real    0m0.383s
>> user    0m0.036s
>> sys    0m0.038s
>>
>>
>> I am a beginner in both methods, but I would prefer play with Python.
>> I'm very surprised to have to wait more than 20 seconds to get an answer.
>> Looking at the engine log, I see that the authentication part is
>> finished after say 3 seconds, then 20 seconds with absolutely no error
>> message, no CPU load, no RAM burst, no nothing.
>> On the SPM, exactly triple null nothing nada niet void is obviously
>> explaining such a delay.
>>
>> I'm wondering if this super hyper sluggishness is somewhat related to
>> the GUI global slowness I'm experiencing like other users since we left
>> 3.2.x, and I would love that some oVirt ninja uses the comparison above
>> to tell what parts in oVirt is used or not that could explain such a
>> difference (database, access to SPM, LVM, network access, whatever...)
>>
>> --
>> Nicolas ECARNOT
>>
>
> The performance problem is inside version 3 of the Python SDK. That is
> one of the reasons that we had to do a new version of the Python SDK for
> version 4 of the engine. If you are using version 4 of the engine then
> you can use version 4 of the SDK:
>
>   https://github.com/oVirt/ovirt-engine-sdk/tree/master/sdk
>
> https://github.com/oVirt/ovirt-engine-sdk/blob/master/sdk/examples/list_vms.py
>
> It should be much faster. Would be nice if you can repeat your test and
> report the results.
>

Hello Juan,

Indeed, you were right. I tried the same from a recent server with a 
recent SDK, and I let you have a look :

# rpm -q python-ovirt-engine-sdk4
python-ovirt-engine-sdk4-4.0.1-1.el7.centos.x86_64

# time ./getMvm.py
62

real	0m1.004s
user	0m0.234s
sys	0m0.031s

And repeating the same test gives a very decent average, so thank you.

-- 
Nicolas ECARNOT