[CASSANDRA-5679] Wide Row calls map method once per column in Hadoop MapReduce

• Type: Bug
• Status: Resolved
• Priority: Normal
• Resolution: Won't Fix
• Labels: cassandra hadoop

Environment

CentOS 6.3, Hadoop 1.1.2, Cassandra 1.2.4

• Severity: Normal
• Assignee: Unassigned
• Reporter: Tony Zhao
• Created: 20/Jun/13 20:38
• Updated: 16/Apr/19 09:32
• Resolved: 20/Jun/13 21:30

Description

When using Cassandra without wide row support in a Hadoop job, the map method gets a number of columns limited by the SlicePredicate every time the map method in the mapper is called; but when using wide row support, the map method is called once for every column. It seems like the limit in SlicePredicate is ignored when wide row set to true.

This prevents in-map reducing code to work (i.e. emit top ten from a mapper).

Issue Links

• is related to: CASSANDRA-4871 get_paged_slice does not obey SlicePredicate