fetch more than 20 rows and display full value of

问题:

I am using CassandraSQLContext from spark-shell to query data from Cassandra. So, I want to know two things one how to fetch more than 20 rows using CassandraSQLContext and second how do Id display the full value of column. As you can see below by default it append dots in the string values.

Code :

val csc = new CassandraSQLContext(sc)
csc.setKeyspace("KeySpace")
val maxDF = csc.sql("SQL_QUERY" )
maxDF.show

Output:

+--------------------+--------------------+-----------------+--------------------+
|                  id|               Col2|              Col3|                Col4| 
+--------------------+--------------------+-----------------+--------------------+
|8wzloRMrGpf8Q3bbk...|             Value1|                 X|                  K1|
|AxRfoHDjV1Fk18OqS...|             Value2|                 Y|                  K2|
|FpMVRlaHsEOcHyDgy...|             Value3|                 Z|                  K3|
|HERt8eFLRtKkiZndy...|             Value4|                 U|                  K4|
|nWOcbbbm8ZOjUSNfY...|             Value5|                 V|                  K5|

回答1:

If you want to print the whole value of a column, you just need to set the argument truncate from the show method to false :

maxDf.show(false)

and if you wish to show more than 20 rows :

// example showing 30 columns of 
// maxDf untruncated
maxDf.show(30, false) 

回答2:

You won't get in nice tabular form instead it will be converted to scala object.

maxDF.take(50)