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Update pig example script to work again. 

Patch by Jeremy Hanna, reviewed by brandonwilliams for CASSANDRA-2487

git-svn-id: https://svn.apache.org/repos/asf/cassandra/branches/cassandra-0.7@1097922 13f79535-47bb-0310-9956-ffa450edef68
This commit is contained in:
Brandon Williams 2011-04-29 19:28:06 +00:00
parent 7105ae1dfd
commit fff2c085c4
2 changed files with 17 additions and 12 deletions
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23
contrib/pig/README.txt
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@ -18,17 +18,22 @@ also set PIG_CONF_DIR to the location of your Hadoop config.
Finally, set the following as environment variables (uppercase,
underscored), or as Hadoop configuration variables (lowercase, dotted):
* PIG_RPC_PORT or cassandra.thrift.port : the port thrift is listening on
* PIG_INITIAL_ADDRESS or cassandra.thrift.address : initial address to connect to
* PIG_RPC_PORT or cassandra.thrift.port : the port thrift is listening on
* PIG_PARTITIONER or cassandra.partitioner.class : cluster partitioner
Run:
For example, against a local node with the default settings, you'd use:
export PIG_INITIAL_ADDRESS=localhost
export PIG_RPC_PORT=9160
export PIG_PARTITIONER=org.apache.cassandra.dht.RandomPartitioner
Then you can build and run it like this:
contrib/pig$ ant
contrib/pig$ bin/pig_cassandra -x local example-script.pig
This will run the test script against your Cassandra instance
and will assume that there is a Keyspace1/Standard1 with some
and will assume that there is a MyKeyspace/MyColumnFamily with some
data in it. It will run in local mode (see pig docs for more info).
If you'd like to get to a 'grunt>' shell prompt, run:
@ -38,24 +43,24 @@ contrib/pig$ bin/pig_cassandra -x local
Once the 'grunt>' shell has loaded, try a simple program like the
following, which will determine the top 50 column names:
grunt> rows = LOAD 'cassandra://Keyspace1/Standard1' USING CassandraStorage();
grunt> cols = FOREACH rows GENERATE flatten($1);
grunt> rows = LOAD 'cassandra://MyKeyspace/MyColumnFamily' USING CassandraStorage() AS (key, columns: bag {T: tuple(name, value)});
grunt> cols = FOREACH rows GENERATE flatten(columns);
grunt> colnames = FOREACH cols GENERATE $0;
grunt> namegroups = GROUP colnames BY $0;
grunt> namegroups = GROUP colnames BY (chararray) $0;
grunt> namecounts = FOREACH namegroups GENERATE COUNT($1), group;
grunt> orderednames = ORDER namecounts BY $0;
grunt> topnames = LIMIT orderednames 50;
grunt> dump topnames;
Slices on columns can also be specified:
grunt> rows = LOAD 'cassandra://Keyspace1/Standard1&slice_start=C2&slice_end=C4&i&limit=1&reversed=true' USING CassandraStorage();
grunt> rows = LOAD 'cassandra://MyKeyspace/MyColumnFamily&slice_start=C2&slice_end=C4&i&limit=1&reversed=true' USING CassandraStorage() AS (key, columns: bag {T: tuple(name, value)});
Binary values for slice_start and slice_end can be escaped such as '\u0255'
Outputting to Cassandra requires the same format from input, so the simplest example is:
grunt> rows = LOAD 'cassandra://Keyspace1/Standard1' USING CassandraStorage();
grunt> STORE rows into 'cassandra://Keyspace1/Standard2' USING CassandraStorage();
grunt> rows = LOAD 'cassandra://MyKeyspace/MyColumnFamily' USING CassandraStorage();
grunt> STORE rows into 'cassandra://MyKeyspace/MyColumnFamily' USING CassandraStorage();
Which will copy the ColumnFamily. Note that the destination ColumnFamily must
already exist for this to work.

6
contrib/pig/example-script.pig
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@ -1,7 +1,7 @@
rows = LOAD 'cassandra://Keyspace1/Standard1' USING CassandraStorage();
cols = FOREACH rows GENERATE flatten($1);
rows = LOAD 'cassandra://MyKeyspace/MyColumnFamily' USING CassandraStorage() AS (key, columns: bag {T: tuple(name, value)});
cols = FOREACH rows GENERATE flatten(columns);
colnames = FOREACH cols GENERATE $0;
namegroups = GROUP colnames BY $0;
namegroups = GROUP colnames BY (chararray) $0;
namecounts = FOREACH namegroups GENERATE COUNT($1), group;
orderednames = ORDER namecounts BY $0;
topnames = LIMIT orderednames 50;