[HBASE-8370] Report data block cache hit rates apart from aggregate cache hit rates

• Type: Improvement
• Status: Closed
• Priority: Minor
• Resolution: Implemented
• Component/s: metrics
• Assignee: Varun Sharma
• Reporter: Varun Sharma
• Created: 17/Apr/13 22:30
• Updated: 16/Jun/22 06:01
• Resolved: 22/Jul/14 04:36

Description

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I am wondering whether the HBase cachingHitRatio metrics that the region server UI shows, can get me a break down by data blocks. I always see this number to be very high and that could be exagerated by the fact that each lookup hits the index blocks and bloom filter blocks in the block cache before retrieving the data block. This could be artificially bloating up the cache hit ratio.

Assuming the above is correct, do we already have a cache hit ratio for data blocks alone which is more obscure ? If not, my sense is that it would be pretty valuable to add one.

Sub-Tasks

• Change block cache percentage metrics to be doubles rather than ints: Closed
• Add L2 metrics: Closed
• Add dumping of DATA block usage to the BlockCache JSON report.: Closed