Home | About | Sematext search-lucene.com search-hadoop.com
 Search Hadoop and all its subprojects:

Switch to Threaded View
Pig >> mail # user >> Pig and XML parsing

Copy link to this message
Pig and XML parsing
Hi All,
I have a lot of small (~2 to 3 MB) XML files that I would like to process. I was thinking along the following lines, please let me know if you have any thoughts on this.

1. Create SeqeunceFiles such that each sequence file between 60 to 64 MB and no XML file is split onto 2 Sequence Files.
2. Write Pig Script to that loads the sequence file, then iterates over individual XML files and analyzes them.
I was planning to use Elephant-Bird to read sequencefiles. Here is what their documentation says:
Hadoop SequenceFiles and Pig

Reading and writing Hadoop SequenceFiles with Pig is supported via classes
SequenceFileStorage. These
classes make use of a
interface, allowing pluggable conversion of key and value instances to and from
Pig data types.
Here's a short example: Suppose you have SequenceFile<Text, LongWritable> data
sitting beneath path input. We can load that data with the following Pig
REGISTER '/path/to/elephant-bird.jar';

%declare SEQFILE_LOADER 'com.twitter.elephantbird.pig.load.SequenceFileLoader';
%declare TEXT_CONVERTER 'com.twitter.elephantbird.pig.util.TextConverter';
%declare LONG_CONVERTER 'com.twitter.elephantbird.pig.util.LongWritableConverter';

pairs = LOAD 'input' USING $SEQFILE_LOADER (
) AS (key: chararray, value: long);
I was looking at XMLLoader from piggybank. Has anyone used XPATH queries in their Pig scripts?