Hbase - Scan for the last 5 records with date as row key

Question

I have a hbase table with 1 column (Expense) and where date is the row key.

How do i get all the records for the past 5 days? Assuming today's date is 2014-04-13? Which filter to use?

I have the data as below

rowkey           Expense
2014-04-13       128
2014-04-12       57
2014-04-11       10
2014-04-10       100 
2014-04-09       797
2014-04-08       67
2014-04-07       56
2014-04-06       14

Answer 1

mashuai's answer will work just fine, but just to offer an alternative, you can also do a reverse scan:

Scan scan = new Scan();
scan.setReversed(true);
scan.setMaxResultSize(5);

Answer 2

You don't need filter. Assuming today is 2014-04-13, you can set start row as 2014-04-09 and the stop row as 2014-04-14. like that

Scan scan = new Scan();
scan.setStartRow(Bytes.toBytes("2014-04-09"));
scan.setStopRow(Bytes.toBytes("2014-04-14"));

Answer 3

According to the documentation setMaxResultSize is probably not what you want:

public Scan setMaxResultSize(long maxResultSize)

Set the maximum result size. The default is -1; this means that no specific maximum result size will be set for this scan, and the global configured value will be used instead. (Defaults to unlimited).

Parameters: maxResultSize - The maximum result size in bytes.

http://hbase.apache.org/apidocs/org/apache/hadoop/hbase/client/Scan.html#setMaxResultSize-long-

You can either use fixed start- and stop-keys, or you could work with a combination of PageFilter and setCaching.