Python driver concistency problem

[Vlad <qa...@yahoo.com.INVALID>]

Hi,
we have three nodes cluster with KS defined as 

CREATE KEYSPACE someks WITH REPLICATION = { 'class' : 'org.apache.cassandra.locator.NetworkTopologyStrategy', 'some-dc': '3' } AND DURABLE_WRITES = true;

next I read with Pyhton (cassandra-driver 3.11) from Cassandra 3.11.3 and get error 

Error from server: code=1200 [Coordinator node timed out waiting for replica nodes' responses] message="Operation timed out - received only 2 responses." info={'received_responses': 2, 'required_responses': 3, 'consistency': 'ALL'}
nor session.default_consistency_level = ConsistencyLevel.QUORUM neither 
query = SimpleStatement("SELECT **********", consistency_level=ConsistencyLevel.QUORUM)
rows = session.execute(query)

helps. What it could be?

Thanks in advance.

RE: [EXTERNAL] Re: Python driver concistency problem

["Durity, Sean R" <SE...@homedepot.com>]

This is a stretch, but are you using authentication and/or authorization? In my understanding the queries executed for you to do the authentication and/or authorization are usually done at LOCAL_ONE (or QUORUM for cassandra user), but maybe there is something that is changed in the security setup? Any UDTs or triggers involved in the query? To me, your error seems more like a query being executed “for you” instead of your actual query.


Sean Durity


From: Vlad <qa...@yahoo.com.INVALID>
Sent: Wednesday, May 22, 2019 6:53 AM
To: user@cassandra.apache.org
Subject: [EXTERNAL] Re: Python driver concistency problem

That's the issue - I do not use consistency ALL. I set QUORUM or ONE but it still performs with ALL.

On Wednesday, May 22, 2019 12:42 PM, shalom sagges <sh...@gmail.com>> wrote:

In a lot of cases, the issue is with the data model.
Can you describe the table?
Can you provide the query you use to retrieve the data?
What's the load on your cluster?
Are there lots of tombstones?

You can set the consistency level to ONE, just to check if you get responses. Although normally I would never use ALL unless I run a DDL command.
I prefer local_quorum if I want my consistency to be strong while keeping Cassandra's high availability.

Regards,







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Re: Python driver concistency problem

[Vlad <qa...@yahoo.com.INVALID>]

That's the issue - I do not use consistency ALL. I set QUORUM or ONE but it still performs with ALL. 

    On Wednesday, May 22, 2019 12:42 PM, shalom sagges <sh...@gmail.com> wrote:
 

 In a lot of cases, the issue is with the data model. 
Can you describe the table?
Can you provide the query you use to retrieve the data?What's the load on your cluster?Are there lots of tombstones?
You can set the consistency level to ONE, just to check if you get responses. Although normally I would never use ALL unless I run a DDL command. 
I prefer local_quorum if I want my consistency to be strong while keeping Cassandra's high availability. 

Regards,






   

Re: Python driver concistency problem

[shalom sagges <sh...@gmail.com>]

In a lot of cases, the issue is with the data model.
Can you describe the table?
Can you provide the query you use to retrieve the data?
What's the load on your cluster?
Are there lots of tombstones?

You can set the consistency level to ONE, just to check if you get
responses. Although normally I would never use ALL unless I run a DDL
command.
I prefer local_quorum if I want my consistency to be strong while keeping
Cassandra's high availability.

Regards,

Re: Python driver concistency problem

[Vlad <qa...@yahoo.com.INVALID>]

Hi,
I do reads in my own Python code, how cqlsh can affect it? 

    On Wednesday, May 22, 2019 12:02 PM, Chakravarthi Manepalli <ma...@gmail.com> wrote:
 

 Hi Vlad,
Maybe the consistency level has been set manually in CQLSH. Did you try checking your consistency level and set it back to normal? (Just a thought, Not sure!!)
On Wed, May 22, 2019 at 2:00 PM Vlad <qa...@yahoo.com.invalid> wrote:

Hi,
we have three nodes cluster with KS defined as 

CREATE KEYSPACE someks WITH REPLICATION = { 'class' : 'org.apache.cassandra.locator.NetworkTopologyStrategy', 'some-dc': '3' } AND DURABLE_WRITES = true;

next I read with Pyhton (cassandra-driver 3.11) from Cassandra 3.11.3 and get error 

Error from server: code=1200 [Coordinator node timed out waiting for replica nodes' responses] message="Operation timed out - received only 2 responses." info={'received_responses': 2, 'required_responses': 3, 'consistency': 'ALL'}
nor session.default_consistency_level = ConsistencyLevel.QUORUM neither 
query = SimpleStatement("SELECT **********", consistency_level=ConsistencyLevel.QUORUM)
rows = session.execute(query)

helps. What it could be?

Thanks in advance.




   

Re: Python driver concistency problem

[Chakravarthi Manepalli <ma...@gmail.com>]

Hi Vlad,

Maybe the consistency level has been set manually in CQLSH. Did you try
checking your consistency level and set it back to normal? (Just a thought,
Not sure!!)

On Wed, May 22, 2019 at 2:00 PM Vlad <qa...@yahoo.com.invalid> wrote:

> Hi,
>
> we have three nodes cluster with KS defined as
>
> *CREATE KEYSPACE someks WITH REPLICATION = { 'class' :
> 'org.apache.cassandra.locator.NetworkTopologyStrategy', 'some-dc': '3' }
> AND DURABLE_WRITES = true;*
>
> next I read with Pyhton (cassandra-driver 3.11) from Cassandra 3.11.3 and
> get error
>
> *Error from server: code=1200 [Coordinator node timed out waiting for
> replica nodes' responses] message="Operation timed out - received only 2
> responses." info={'received_responses': 2, 'required_responses': 3,
> 'consistency': 'ALL'}*
>
> nor *session.default_consistency_level = ConsistencyLevel.QUORUM* neither
>
> *query = SimpleStatement("SELECT **********",
> consistency_level=ConsistencyLevel.QUORUM)rows = session.execute(query)*
>
> helps. What it could be?
>
> Thanks in advance.
>
>