jpountz opened a new pull request, #14823: URL: https://github.com/apache/lucene/pull/14823
`TieredMergePolicy` currently allows 10 segments per tier. With Lucene being increasingly deployed with separate indexing and search tiers that get updated via segment-based replication, I believe that it would make sense for Lucene to have more aggressive merging defaults, a price that is only paid once on the indexing tier, but that benefits all search nodes that serve queries for this index. Note that this is still a somewhat conservative default, applications with low latency requirements and low update rates will likely want to go even further, with 4 segments per tier, or even 2. `BaseMergePolicyTestCase#testSimulateAppendOnly` reports a write amplification increase from 3.4 to 3.8, while `BaseMergePolicyTestCase#testSimulateUpdates` reports a write amplification increase from 4.5 to 4.9. In exchange, the number of segments between the floor and max segment sizes decreases by about 20%. This should especially help queries that have a high per-segment overhead: PK lookups, point queries, multi-term queries and vector searches. -- This is an automated message from the Apache Git Service. To respond to the message, please log on to GitHub and use the URL above to go to the specific comment. To unsubscribe, e-mail: issues-unsubscr...@lucene.apache.org For queries about this service, please contact Infrastructure at: us...@infra.apache.org --------------------------------------------------------------------- To unsubscribe, e-mail: issues-unsubscr...@lucene.apache.org For additional commands, e-mail: issues-h...@lucene.apache.org
