Examples for output_query with PIG and Cassandra CqlStorage

Question

I am trying to write data to Cassandra CQL 3 Table using:

STORE G INTO 'cql://keyapse/col_family?output_query=not sure what goes here' USING CqlStorage();

What does the output_query look like:

UPDATE col_family SET col1=$0, col2=$3 WHERE KEY=$2

Answer 1

You need to take care on both: the storage URL and the data preparation. This is an example that should work.

Suppose you need to insert data in the following structure:

CREATE TABLE example (
  row_id text PRIMARY KEY,

  value1 text,

  value2 int
);

You need to prepare the data like this:

data_to_insert = FOREACH some_set_of_data GENERATE 

    TOTUPLE(TOTUPLE('row_id',row_id)), TOTUPLE(value1, value2) ;

Finally the storing statement will be:

STORE data_to_insert INTO 'cql://my/example?output_query=update example set value1 @ # , value2 @ #' USING CqlStorage();

Answer 2

This blog has some details, but no specific examples: http://www.datastax.com/dev/blog/cql3-table-support-in-hadoop-pig-and-hive

Answer 3

I wrote up a brief how to on using PIG as a Data loader for Cassandra using CQL3.

http://www.schappet.com/pig_cassandra_bulk_load

Basic setup includes the info from @Kernald

STORE data_to_insert INTO
  'cql://myschema/example?output_query=update example set value1 @ #,value2 @ #' USING CqlStorage();