The documentation for IntWritable doesn't explicitly mention it being fixed-length or not [1]. But, given there's also a VIntWritable [2], I think IntWritable is always 4 bytes.
[1] http://hadoop.apache.org/docs/current/api/org/apache/hadoop/io/IntWritable.html [2] http://hadoop.apache.org/docs/current/api/org/apache/hadoop/io/VIntWritable.html On Thu, Jul 4, 2013 at 1:02 PM, Pradeep Gollakota <[email protected]>wrote: > Not sure about Avro<Integer> is 4 bytes or not. But IntWritable is > variable length. If the number can be represented in less than 4 bytes, it > will. > On Jul 4, 2013 2:22 AM, "Dan Filimon" <[email protected]> wrote: > >> Well, I got it working eventually. :) >> >> First of all, I'll mention that I'm using the new MapReduce API, so no >> AvroMapper/AvroReducer voodoo for me. I'm just using the AvroKey<> and >> AvroValue<> wrappers and once I set the right properties using AvroJob's >> static methods (AvroJob.setMapOutputValueSchema() for example) and set the >> input to be an AvroKeyInputFormat, everything worked out fine. >> >> About the writables, I'm interested to know whether it'd be better to use >> Avro equivalent classes: AvroKey<Integer> or IntWritable. I assume the >> speed/size of these two should be the same 4 bytes? >> >> >> On Thu, Jul 4, 2013 at 2:48 AM, Martin Kleppmann >> <[email protected]>wrote: >> >>> Hi Dan, >>> >>> You're stepping off the documented path here, but I think that although >>> it might be a bit of work, it should be possible. >>> >>> Things to watch out for: you might not be able to use >>> AvroMapper/AvroReducer so easily, and you may have to mess around with the >>> job conf a bit (Avro-configured jobs use their own shuffle config with >>> AvroKeyComparator, which may not be what you want if you're also trying to >>> use writables). I'd suggest simply reading the code in >>> org.apache.avro.mapred[uce] -- it's not too complicated. >>> >>> Whether Avro files or writables (i.e. Hadoop sequence files) are better >>> for you depends mostly on which format you'd rather have your data in. If >>> you want to read the data files with something other than Hadoop, Avro is >>> definitely a good option. Also, Avro data files are self-describing (due to >>> their embedded schema) which makes them pleasant to use with tools like Pig >>> and Hive. >>> >>> Martin >>> >>> >>> On 3 July 2013 10:12, Dan Filimon <[email protected]> wrote: >>> >>>> Hi! >>>> >>>> I'm working on integrating Avro into our data processing pipeline. >>>> We're using quite a few standard Hadoop and Mahout writables >>>> (IntWritable, VectorWritable). >>>> >>>> I'm first going to replace the custom Writables with Avro, but in terms >>>> of the other ones, how important would you say it is to use >>>> AvroKey<Integer> instead of IntWritable for example? >>>> >>>> The changes will happen gradually but are they even worth it? >>>> >>>> Thanks! >>>> >>> >>> >>
