[HBASE-15640] L1 cache doesn't give fair warning that it is showing partial stats only when it hits limit

• Type: Sub-task
• Status: Resolved
• Priority: Major
• Resolution: Fixed
• Fix Version/s: 1.3.0, 0.98.19, 1.2.2, 2.0.0
• Component/s: BlockCache
• Hadoop Flags: Reviewed

Release Note

The blockcache UI tab would stop refreshing at 100k blocks (configurable, see "hbase.ui.blockcache.by.file.max"), which isn't very many blocks when doing a big cache, giving a misleading picture of the content of L1 and/or L2 cache. Up the default limit to 1M blocks (UI takes a while but just a few seconds counting over 1M blocks).

Also, when beyond the limit give the user a noticeable WARNING in the UI.

• Assignee: Michael Stack
• Reporter: Michael Stack
• Created: 12/Apr/16 23:28
• Updated: 09/Nov/17 00:43
• Resolved: 20/Apr/16 21:28

Description

I was baffled looking at L1 Cache because it was stuck at 100k blocks and only 'loading' 3G of data according to the UI. When I looked in log, all the numbers looked write in the Cache summary reported in log.

Turns out our buckecache UI template will cut off calculating stats at a limit --which is probably what we want – but the fact that it has done this should be more plain.