Hi, If you intend to use those counters in further functions then I think Hadoop will take care this by itself, you can explore combiner for the same. In Sequence file mapfile and index files has its own functionality and as per my understanding index file expect offset to move over map file and logically you can't use it for counter.
Sent via Rocket from my HTC ----- Reply message ----- From: "Elazar Leibovich" <elaz...@gmail.com> To: <user@hadoop.apache.org> Subject: Saving counters in Mapfile Date: Wed, Jul 24, 2013 3:27 AM Hi, A common use case one want an ordered structure for, is for saving counters. Naturally, I wanted to save the counters in a Mapfile: for (long ix = 0; ix < MAXVALUE; ix++) { mapfile.append(new Text("counter key of val " + ix), new LongWritable(ix)); } This however looks a bit inefficient. We'll store two files, and an index file. The index file will contain an offset (long) to the sequence file, which would contain a single long. I'd rather have only the index file, that would store the counter value instead of offsets. Is there a way to do that with Mapfile? Perhaps there's a better way to save searchable counters in HDFS file? Thanks,