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HBase >> mail # user >> Question on the number of column families


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RE: Question on the number of column families
Thank you Ted.

But RowFilter class has no method that can be uses to set which column family is essential. (Actually no built-in filter class provides such a method)

So, if I (ever) want to apply the 'dummy' column family technique(?), it seems that I must do as follows:

- Write my own filter that's a subclass of the RowFilter.
- In that filter class, override isFamilyEssential() method to return true only when the name of the 'dummy' column family is passed as an argument.

Now, HBase calls isFamilyEssential() method of my filter object for all the column families including the 'dummy' column family, and in result only loads the 'dummy' column family and happily filters rowkey using the KeyValue objects from the 'dummy' column family HFile(s).

Am I right?

BTW, it would be nice to have a method like 'setEssentialColumnFamilies(byte[][] names)' to set the essential families manually, since no built-in filter intelligently determines which column family is essential, except for SingleColumnValueFilter.

Thanks.