[HBASE-11144] Filter to support scanning multiple row key ranges

• Type: Improvement
• Status: Closed
• Priority: Major
• Resolution: Fixed
• Fix Version/s: 1.1.0, 0.98.21, 2.0.0
• Component/s: Filters
• Hadoop Flags: Reviewed

Release Note

MultiRowRangeFilter is a filter to support scanning multiple row key ranges. If the number of the ranges is small, using multiple scans can also do the same thing and can work well. But when the number of ranges are quite big (e.g. millions), use the MultiRowRangeFilter will be nice. In this filter, the ranges will be sorted and merged, so users do not have to take care of ranges are not continuous. And if users are using something like rest, thrift or pig to access the data the filter might be the practical solution.

• Assignee: Jiajia Li
• Reporter: Jiajia Li
• Created: 09/May/14 05:27
• Updated: 22/Jul/16 17:15
• Resolved: 13/Jan/15 15:05

Description

HBase is quite efficient when scanning only one small row key range. If user needs to specify multiple row key ranges in one scan, the typical solutions are: 1. through FilterList which is a list of row key Filters, 2. using the SQL layer over HBase to join with two table, such as hive, phoenix etc. However, both solutions are inefficient. Both of them can’t utilize the range info to perform fast forwarding during scan which is quite time consuming. If the number of ranges are quite big (e.g. millions), join is a proper solution though it is slow. However, there are cases that user wants to specify a small number of ranges to scan (e.g. <1000 ranges). Both solutions can’t provide satisfactory performance in such case.
We provide this filter (MultiRowRangeFilter) to support such use case (scan multiple row key ranges), which can construct the row key ranges from user specified list and perform fast-forwarding during scan. Thus, the scan will be quite efficient.