| Introduction |
| ============ |
| |
| WordCount hadoop example: Inserts a bunch of words across multiple rows, |
| and counts them, with RandomPartitioner. The word_count_counters example sums |
| the value of counter columns for a key. |
| |
| The scripts in bin/ assume you are running with cwd of examples/word_count. |
| |
| |
| Running |
| ======= |
| |
| First build and start a Cassandra server with the default configuration*. Ensure that the Thrift |
| interface is enabled, either by setting start_rpc:true in cassandra.yaml or by running |
| `nodetool enablethrift` after startup. |
| Once Cassandra has started and the Thrift interface is available, run |
| |
| contrib/word_count$ ant |
| contrib/word_count$ bin/word_count_setup |
| contrib/word_count$ bin/word_count |
| contrib/word_count$ bin/word_count_counters |
| |
| In order to view the results in Cassandra, one can use bin/cqlsh and |
| perform the following operations: |
| $ bin/cqlsh localhost |
| > use cql3_wordcount; |
| > select * from output_words; |
| |
| The output of the word count can now be configured. In the bin/word_count |
| file, you can specify the OUTPUT_REDUCER. The two options are 'filesystem' |
| and 'cassandra'. The filesystem option outputs to the /tmp/word_count* |
| directories. The cassandra option outputs to the 'output_words' column family |
| in the 'cql3_wordcount' keyspace. 'cassandra' is the default. |
| |
| Read the code in src/ for more details. |
| |
| The word_count_counters example sums the counter columns for a row. The output |
| is written to a text file in /tmp/word_count_counters. |
| |
| *It is recommended to turn off vnodes when running Cassandra with hadoop. |
| This is done by setting "num_tokens: 1" in cassandra.yaml. If you want to |
| point wordcount at a real cluster, modify the seed and listenaddress |
| settings accordingly. |
| |
| |
| Troubleshooting |
| =============== |
| |
| word_count uses conf/logback.xml to log to wc.out. |
| |
