[CASSANDRA-13040] Estimated TS drop-time histogram updated with Cell.NO_DELETION_TIME

• Type: Bug
• Status: Resolved
• Priority: Normal
• Resolution: Fixed
• Fix Version/s: 3.0.11, 3.10, 4.0-alpha1, 4.0
• Severity: Normal
• Assignee: Stefan Podkowinski
• Reporter: Stefan Podkowinski

Authors

Stefan Podkowinski

Reviewers

Jason Brown

• Created: 13/Dec/16 10:51
• Updated: 15/May/20 08:02
• Resolved: 13/Dec/16 13:16

Description

Starting with 3.0, MetadataCollector.updateLocalDeletionTime(int newLocalDeletionTime) will be called with cell.localDeletionTime() in order to update the min/max deletion times as well as the estimatedTombstoneDropTime histogram. Currently this also happens for Cell.NO_DELETION_TIME (Integer.MAX_VALUE), which causes the histogram to be called for every regular cell.

This can be easily verified by using sstablemetadata on any sstable. You should be able to find a very high value for 2147483647 in the "Estimated tombstone drop times" section.

At this point, I don't think this is causing serious harm, but could be a performance issue (see linked ticket). Calculated droppable TS times should not be affected.

Issue Links

• is related to: CASSANDRA-13024 Droppable Tombstone Ratio Calculation
• is related to: CASSANDRA-13038 33% of compaction time spent in StreamingHistogram.update()