[IMPALA-4187] Switch RPC latency metrics to histograms

• Type: Improvement
• Status: Resolved
• Priority: Major
• Resolution: Fixed
• Affects Version/s: Impala 2.7.0
• Fix Version/s: Impala 2.8.0
• Component/s: Backend
• Labels: observability
• Target Version: Impala 2.8.0
• Assignee: Henry Robinson
• Reporter: Henry Robinson
• Created: 22/Sep/16 17:39
• Updated: 27/Sep/16 17:27
• Resolved: 27/Sep/16 17:27

Description

The metrics measuring RPC latencies capture average / min / max, which isn't so interesting for latency distributions. We have HistogramMetric and should use it.

Doing so requires implementing HistogramMetric::Reset() so that we keep the functionality that already exists in /rpcz.