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From Dave Hardcastle <>
Subject Iterators that alter key-values
Date Fri, 15 May 2015 17:26:53 GMT

I've always assumed that the last iterator in the stack can make arbitrary
changes to keys and values, including not returning the keys in sorted
order. I know that SortedKeyValueIterator says that "anything implementing
this interface should return keys in sorted order" - but I don't see a good
reason that has to be true for the final iterator. This assumption seems to
be backed up by the manual which says that "the only safe way to generate
additional data in an iterator is to alter the current key-value pair" - it
doesn't say that making arbitrary modifications to the rowkey or key is

I have a situation where I am making a transformation of the rowkey that
may not preserve the ordering of the keys. When I scan for individual
ranges I get the correct results. When I scan for two ranges using a
BatchScanner, I get lots of data back which is not in the ranges I queried
for. I am not explicitly checking that I have not gone beyond the range,
but that should not be necessary as I am not doing any seeking, only
consuming the key-values I receive.

So, my main question is whether the last iterator is allowed to not return
keys in sorted order?



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