lower chunk size, and memory usage
lower chunk size, and memory usage

neozhangthe1/dedupe,tfmorris/dedupe,tfmorris/dedupe,01-/dedupe,datamade/dedupe,dedupeio/dedupe,nmiranda/dedupe,pombredanne/dedupe,dedupeio/dedupe-examples,davidkunio/dedupe,pombredanne/dedupe,dedupeio/dedupe,datamade/dedupe,nmiranda/dedupe,neozhangthe1/dedupe,davidkunio/dedupe,01-/dedupe