[CASSANDRA-3234] LeveledCompaction has several performance problems

• Type: Bug
• Status: Resolved
• Priority: Normal
• Resolution: Fixed
• Fix Version/s: 1.0.0
• Labels: lcs
• Severity: Normal
• Assignee: Jonathan Ellis
• Reporter: Jonathan Ellis

Authors

Jonathan Ellis

Reviewers

Brandon Williams

• Created: 20/Sep/11 23:47
• Updated: 16/Apr/19 09:32
• Resolved: 23/Sep/11 13:56

Description

Two main problems:

• BF size calculation doesn't take into account LCS breaking the output apart into "bite sized" sstables, so memory use is much higher than predicted
• ManyToMany merging is slow. At least part of this is from running the full reducer machinery against single input sources, which can be optimized away.