[HBASE-22422] Retain an ByteBuff with refCnt=0 when getBlock from LRUCache

• Type: Sub-task
• Status: Resolved
• Priority: Major
• Resolution: Fixed
• Fix Version/s: 3.0.0-alpha-1, 2.3.0
• Component/s: BlockCache
• Hadoop Flags: Reviewed
• Assignee: Zheng Hu
• Reporter: Zheng Hu
• Created: 15/May/19 04:02
• Updated: 23/Jan/20 17:29
• Resolved: 28/May/19 02:16

Description

After runing YCSB scan/get benchmark in our XiaoMi cluster, we found the get QPS dropped from 25000/s to hunderds per second in a cluster with five nodes.

After enable the debug log at YCSB client side, I found the following stacktrace , see https://issues.apache.org/jira/secure/attachment/12968745/image-2019-05-15-12-00-03-641.png.

After looking into the stractrace, I can ensure that the zero refCnt block is an intermedia index block, see [2] http://hbase.apache.org/images/hfilev2.png

Need a patch to fix this.

Issue Links

• links to: GitHub Pull Request #242