[IMPALA-2493] Allow histogram() function to either return full string value or accept optional max length argument

• Type: Improvement
• Status: Resolved
• Priority: Minor
• Resolution: Workaround
• Affects Version/s: Impala 2.2.4
• Component/s: Backend
• Labels: hue ramp-up
• Target Version: Product Backlog
• Assignee: Unassigned
• Reporter: Jenny Kim
• Created: 07/Oct/15 01:10
• Updated: 04/Jan/17 23:58
• Resolved: 12/Apr/16 16:52

Description

Hue uses Impala's histogram() function to provide type-ahead assist for scalar columns and nested types with a sample of values.

Currently strings are truncated to a max_length of 10 chars: http://github.mtv.cloudera.com/CDH/Impala/blob/cdh5-trunk/be/src/exprs/aggregate-functions.cc#L805

Hue needs the full string values though, is it possible to pass in an option to disable truncation or set a new max length?