[CASSANDRA-4341] Small SSTable Segments Can Hurt Leveling Process

• Type: Improvement
• Status: Resolved
• Priority: Low
• Resolution: Fixed
• Fix Version/s: 1.1.2
• Labels: compaction lcs
• Assignee: Jonathan Ellis
• Reporter: Benjamin Coverston

Authors

Jonathan Ellis

Reviewers

Yuki Morishita

• Created: 14/Jun/12 16:39
• Updated: 16/Apr/19 09:32
• Resolved: 22/Jun/12 18:16

Description

This concerns:

static int MAX_COMPACTING_L0 = 32;

Repair can create very small SSTable segments. We should consider moving to a threshold that takes into account the size of the files brought into compaction rather than the number of files for this and similar situations. Bringing the small files from L0 to L1 magnifies the issue.

If there are too many very small files in L0 perhaps even an intermediate compaction would even reduce the magnifying effect of a L0 to L1 compaction.

Issue Links

• is related to: CASSANDRA-6698 Many too small SSTables when full repair