[HBASE-18532] Improve cache related stats rendered on RS UI

• Type: Improvement
• Status: Resolved
• Priority: Major
• Resolution: Fixed
• Affects Version/s: 1.1.2
• Fix Version/s: 1.4.0, 2.0.0-alpha-3, 2.0.0
• Component/s: regionserver, UI
• Hadoop Flags: Reviewed
• Assignee: Biju Nair
• Reporter: Biju Nair
• Created: 07/Aug/17 18:39
• Updated: 21/Mar/18 22:14
• Resolved: 23/Aug/17 20:27

Description

The stats currently rendered for L1 and L2 cache are incorrect. Refer to the attached screenshots of stats from a cluster showing the combined cache stats, L1 stats and L2 stats. For e.g. the combined stats shows 38 GB used for cache while if we sum size of L1 and L2 cache the value is way less. One way we can improve this is to use the same stats used to populate the combined stats to render the values of L1 & L2 cache. Also for usability we can remove the table with details with BucketCache buckets from the L2 cache stats since this is going to be long for any installation using L2 cache. This will help in understanding the cache usage better. Thoughts? If there are no concerns will submit a patch.