[HBASE-3565] Add metrics to keep track of slow HLog appends

• Type: Improvement
• Status: Closed
• Priority: Major
• Resolution: Fixed
• Fix Version/s: 0.94.0
• Component/s: metrics, regionserver
• Labels: monitoring
• Hadoop Flags: Reviewed
• Assignee: Mubarak Seyed
• Reporter: Benoit Sigoure
• Created: 25/Feb/11 01:40
• Updated: 12/Oct/12 05:34
• Resolved: 11/Jan/12 19:55

Description

Whenever an edit takes too long to be written to an HLog, HBase logs a warning such as this one:

2011-02-23 20:03:14,703 WARN org.apache.hadoop.hbase.regionserver.wal.HLog: IPC Server handler 21 on 60020 took 15065ms appending an edit to hlog; editcount=126050

I would like to have a counter incremented each time this happens and this counter exposed via the metrics stuff in HBase so I can collect it in my monitoring system.