Slow queries (only when using python driver)

[Martin Brambati]

Hi there, I'm using the python driver for a django app. My column_family has 1M registries aprox. 

Each simple query takes 10 secs and it's a simple one, by PK should't take so long. When I execute the query via cqlsh it takes a few miliseconds, very fast.

This is the method where I try to execute the query:

def execute(self, cql, kargs):

            res = self.get_session().execute(cql, kargs)

            return res

and the query looks like:

select * keyspace.from cfname where id=12334343;

Thanks!

[Adam Holmberg]

I don't see anything unusual with the small amount of Python you showed. Curious, what's inside of 'self.get_session()'?

I'm assuming the malformed query is just a typo.

We may need a little more information about your Cassandra/cqlsh and driver versions, data model, and surrounding code, to help out.

Regards,

Adam Holmberg

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[Martin Brambati]

We just found out the problem (I think), had to add max_schema_agreement_wait=0.01 on initialize... that helped with speed, also we configured cluster.set_core_connections_per_host(HostDistance.LOCAL, 1).

The problem is the connect, each connect takes more than 10 secs...

The malformed query is just a typo :P

--

Martin Brambati

Engineering / Mendoza / Argentina

www.Eventbrite.com

[Adam Holmberg]

max_schema_agreement_wait only comes into play when modifying schema. Are you changing schema often?

Regarding connect time: 10s is surprisingly high. Independent of possible network issues, this should not really affect a discussion of query execution if your session is long-lived (i.e. you would not typically be creating many sessions in an application).

Adam

[Martin Brambati]

Yes, one session only (Singleton), and I really don't know why it takes so long. The initial topic should be changed to "cluster.connect speed problem".

Thanks!

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