I don't know what happened to my original post but it got truncated.
Let me try again :
software versions : apache-cassandra-2.0.1 hadoop-2.1.0-beta
I have been experimenting with using hadoop for a map/reduce operation on
cassandra,
outputting to the CqlOutputFormat.class.
I based my first program fairly closely on the famous WordCount example in
examples/hadoop_cql3_word_count
except --- I set my output colfamily to have a bigint primary key :
CREATE TABLE archive_recordids ( recordid bigint , count_num bigint, PRIMARY
KEY (recordid))
and simply tried setting this key as one of the keys in the output map :
keys.put("recordid", ByteBufferUtil.bytes(recordid.longValue()));
but it always failed with a strange error :
java.io.IOException: InvalidRequestException(why:Key may not be empty)
After trying to make it more similar to WordCount,
I eventually realized the one difference was datatype of the primary key
of the output colfamily:
WordCount has text
I had bigint
I changed mine to text :
CREATE TABLE archive_recordids ( recordid text , count_num bigint, PRIMARY KEY
(recordid))
and set the primary key *twice* in the reducer :
keys.put("recordid", ByteBufferUtil.bytes(String.valueOf(recordid)));
context.getConfiguration().set(PRIMARY_KEY,String.valueOf(recordid));
and it then worked perfectly.
Is there a restriction in cassandra-hadoop-cql support that
the output colfamily's primary key(s) must be text?
And does that also apply to DELETE?
Or am I doing it wrong?
Or maybe there is some other OutputFormatter that I could use that would work?
Cheers, John
