Github user renato2099 commented on the pull request:
https://github.com/apache/gora/pull/23#issuecomment-94309903
Thanks a lot for the explanation @gerhardgossen! And yes this is a problem
we have seen in other data stores as well. I mean managing complex data types
because not all data stores provide the same functionality. For example, in
gora-cassandra depending on your mapping file, you could create subcolumns
inside a super column or even separated columns. Then when updating maps, you
could end up updating a whole column even when a single value was modified
inside an array or map. This behaviour is of course wrong. I guess this is also
happening in accumulo per your test.
I think there is a trade-off here between generating a column for each
specific value of a map/array which leads to a more complex scan operation or
using a single column to store them all which leads to the current behaviour.
In Cassandra, arrays and maps can be now stored natively, so I guess we
will be using them soon instead of adding this extra "mapping" complexity. Do
you know if Accumulo stores complex data types or if it plans to?
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