[HIVE-7805] Support running multiple scans in hbase-handler

• Type: Improvement
• Status: Patch Available
• Priority: Major
• Resolution: Unresolved
• Affects Version/s: 0.14.0
• Component/s: HBase Handler
• Assignee: Andrew Mains
• Reporter: Andrew Mains
• Created: 20/Aug/14 19:54
• Updated: 26/Apr/15 02:01

Description

Currently, the HiveHBaseTableInputFormat only supports running a single scan. This can be less efficient than running multiple disjoint scans in certain cases, particularly when using a composite row key. For instance, given a row key schema of:

struct<bucket int, time timestamp>

if one wants to push down the predicate:

bucket IN (1, 10, 100) AND timestamp >= 1408333927 AND timestamp < 1408506670

it's much more efficient to run a scan for each bucket over the time range (particularly if there's a large amount of data per day). With a single scan, the MR job has to process the data for all time for buckets in between 1 and 100.

hive should allow HBaseKeyFactory's to decompose a predicate into one or more scans in order to take advantage of this fact.