[CASSANDRA-8918] Optimise compaction performance for unique partition keys

• Type: Improvement
• Status: Resolved
• Priority: Normal
• Resolution: Later
• Assignee: Unassigned
• Reporter: Benedict Elliott Smith
• Created: 05/Mar/15 13:20
• Updated: 16/Apr/19 09:31
• Resolved: 05/Mar/15 18:44

Description

Related to the raft of improvements we're looking at for improving the CPU burden of merge, if we can demonstrate that an entire partition key is unique to a given file (which is quite easily done) we can avoid materialising any of the row, and simply copy the data wholesale, with potentially some small modifications to the index file data if it has clustering column index entries, and special treatment of tombstones (most simple would be to only check there are no tombstones to purge, and abort this approach if so).

Issue Links

• relates to: CASSANDRA-8731 Optimise merges involving multiple clustering columns
• relates to: CASSANDRA-8923 Improve MergeIterator performance for binary prefix comparable data