[CASSANDRA-12580] Fix merkle tree size calculation

• Type: Bug
• Status: Resolved
• Priority: Normal
• Resolution: Fixed
• Fix Version/s: 2.2.9, 3.0.10, 3.10
• Component/s: Legacy/Streaming and Messaging
• Severity: Normal
• Since Version: 2.1.1
• Assignee: Paulo Motta
• Reporter: Paulo Motta

Authors

Paulo Motta

Reviewers

Yuki Morishita

• Created: 31/Aug/16 16:56
• Updated: 16/Apr/19 09:30
• Resolved: 29/Sep/16 20:07

Description

On CASSANDRA-5263 it was introduced dynamic merkle tree sizing based on estimated number of partitions as estimatedDepth = lg(numPartitions), but on CompactionManager.doValidationCompaction this is being calculated as:

int depth = numPartitions > 0 ? (int) Math.min(Math.floor(Math.log(numPartitions)), 20) : 0;

This is actually calculating ln(numPartitions) (base-e) instead of lg(numPartitions) (base-2), which causes merkle trees to lose resolution, what may result in overstreaming.

Issue Links

• relates to: CASSANDRA-12846 Repair is taking too much time