[HDFS-16982] Use the right Quantiles Array for Inverse Quantiles snapshot

• Type: Bug
• Status: Resolved
• Priority: Minor
• Resolution: Fixed
• Affects Version/s: 3.4.0
• Fix Version/s: 3.4.0
• Component/s: datanode, metrics
• Labels: pull-request-available
• Target Version/s: 3.4.0
• Hadoop Flags: Reviewed
• Assignee: Ravindra Dingankar Assign to me
• Reporter: Ravindra Dingankar
• Created: 14/Apr/23 05:42
• Updated: 28/Jan/24 07:07
• Resolved: 18/Apr/23 17:49

Description

HDFS-16949 introduced InverseQuantiles. However during snapshot for Inverse Quantiles we were still trying to access values from previous snapshot based on the Quantile Array declared in MutableQuantiles. ( Quantile(.50, .050), Quantile(.75, .025), Quantile(.90, .010), Quantile(.95, .005), Quantile(.99, .001) )

For InverseQuantiles we wont have these values ( except for Quantile(.50, .050) ) thus except for 50 Percentile snapshot wont return any value for the remaining quantiles.

Fix is to use the correct Quantiles Array to retrieve values during snapshot. The new UTs verify this behavior.

Issue Links

• links to: GitHub Pull Request #5556