Hi Michael,
Thank you for the quick reply.
So you are suggesting to convert this int value(UUID comes back as int via
Spark SQL) to hex?
And selection is just a example to highlight the UUID convertion issue.
So in Cassandra it should be
SELECT id, workflow FROM sam WHERE dept='blah';
And in Spark with Python:
SELECT distinct id, dept, workflow FROM samd WHERE dept='blah';
Best,
Rajesh R
________________________________
From: Laing, Michael [michael.la...@nytimes.com]
Sent: 24 May 2016 11:40
To: user@cassandra.apache.org
Subject: Re: UUID coming as int while using SPARK SQL
Try converting that int from decimal to hex and inserting dashes in the
appropriate spots - or go the other way.
Also, you are looking at different rows, based upon your selection criteria...
ml
On Tue, May 24, 2016 at 6:23 AM, Rajesh Radhakrishnan
<rajesh.radhakrish...@phe.gov.uk<redir.aspx?REF=5W78rpYMgC0K3ToHNzRZiPAT8hnWs6gnRkq-A41T1FsrnpaZwYPTCAFtYWlsdG86UmFqZXNoLlJhZGhha3Jpc2huYW5AcGhlLmdvdi51aw..>>
wrote:
Hi,
I got a Cassandra keyspace, but while reading the data(especially UUID) via
Spark SQL using Python is not returning the correct value.
Cassandra:
--------------
My table 'SAM'' is described below:
CREATE table ks.sam (id uuid, dept text, workflow text, type double primary
key (id, dept))
SELECT id, workflow FROM sam WHERE dept='blah';
The above example CQL gives me the following
id | workflow
--------------------------------------+------------
9547v26c-f528-12e5-da8b-001a4q3dac10 | testWK
Spark/Python:
------------------
from pyspark import SparkConf
from pyspark.sql import SQLContext
import pyspark_cassandra
from pyspark_cassandra import CassandraSparkContext
....
conf =
SparkConf().set("spark.cassandra.connection.host",IP_ADDRESS).set("spark.cassandra.connection.native.port",PORT_NUMBER)
sparkContext = CassandraSparkContext(conf = conf)
sqlContext = SQLContext(sparkContext)
samTable =sparkContext.cassandraTable("ks", "sam").select('id',
'dept','workflow')
samTable.cache()
samdf.registerTempTable("samd")
sparkSQLl ="SELECT distinct id, dept, workflow FROM samd WHERE
workflow='testWK'
new_df = sqlContext.sql(sparkSQLl)
results = new_df.collect()
for row in results:
print "dept=",row.dept
print "wk=",row.workflow
print
"id=",row.id<redir.aspx?REF=hwbfDfTNtMn5fA8cehCaM6eYnx4zZc72sCEXSlez7vornpaZwYPTCAFodHRwOi8vcm93Lmlk>
...
The Python code above prints the following:
dept=Biology
wk=testWK
id=293946894141093607334963674332192894528
You can see here that the id (uuid) whose correct value at Cassandra is '
9547v26c-f528-12e5-da8b-001a4q3dac10' but via Spark I am getting an int
'29394689414109360733496367433219289452'.
What I am doing wrong here? How to get the correct UUID value from Cassandra
via Spark/Python ? Please help me.
Thank you
Rajesh R
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