Question

I’m trying to use the HBase Java client to answer the following question as efficiently as possible:

For a given row and a given column family, which qualifiers have a certain prefix?

I’d likely use a QualifierFilter with a BinaryPrefixComparator. Would this work? My intuition is that it should be possible to do this without sending the corresponding cell contents of those columns, right? Would something like a KeyOnlyFilter work here?

Answer 1

Here’s what I got to work. KeyOnlyFilter works splendidly, as does ColumnPrefixFilter, which as far as I can tell is equivalent to QualifierFilter and BinaryPrefixComparator.

Scan scan = new Scan(MY_ROW, getSuccessor(MY_ROW))
                .addFamily(MY_COLFAM)
                .setMaxVersions(1)
                .setFilter(
                    new FilterList(
                        Operator.MUST_PASS_ALL, Arrays.<Filter>asList(
                            new KeyOnlyFilter(),
                            new ColumnPrefixFilter(MY_PREFIX)
                        )));

Where getSuccessor() is a function that merely adds a null byte to the end.