How filter Scan of HBase by part of row key?
Fuzzy row approach is efficient for this kind of requirement and when data is is huge : As explained by this article FuzzyRowFilter takes as parameters row key and a mask info.
In example above, in case we want to find last logged in users and row key format is userId_actionId_timestamp
(where userId
has fixed length of say 4 chars), the fuzzy row key we are looking for is ????_login_
. This translates into the following params for FuzzyRowKey:
FuzzyRowFilter rowFilter = new FuzzyRowFilter(
Arrays.asList(
new Pair<byte[], byte[]>(
Bytes.toBytesBinary("\x00\x00\x00\x00_login_"),
new byte[] {1, 1, 1, 1, 0, 0, 0, 0, 0, 0, 0})));
Would suggest to go through hbase-the-definitive guide -->Client API: Advanced Features