[jira] [Commented] (CASSANDRA-9829) Dynamically adjust LCS level sizes

["Michael Semb Wever (Jira)" <ji...@apache.org>]

    [ https://issues.apache.org/jira/browse/CASSANDRA-9829?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel&focusedCommentId=17715708#comment-17715708 ] 

Michael Semb Wever commented on CASSANDRA-9829:
-----------------------------------------------

[~jbellis], [~blambov], do we still wish to keep this ticket open with CEP-26 (UCS: CASSANDRA-18397) landing in 5.0 ? 

> Dynamically adjust LCS level sizes
> ----------------------------------
>
>                 Key: CASSANDRA-9829
>                 URL: https://issues.apache.org/jira/browse/CASSANDRA-9829
>             Project: Cassandra
>          Issue Type: New Feature
>          Components: Local/Compaction
>            Reporter: Jonathan Ellis
>            Priority: Normal
>              Labels: compaction, lcs, performance
>             Fix For: 5.x
>
>
> LCS works best when the top level is full.  Then 90% of reads can be served from a single sstable.  By contrast if the top level is only 10% full then 90% of reads will be served from two.  This results in worse performance as well as confused users.
> To address this, we can adjust the ideal top level size to how much data is actually in it (and set each corresponding lower level to 1/10 of the next one above).
> (This is an idea [from rocksdb|https://www.reddit.com/r/IAmA/comments/3de3cv/we_are_rocksdb_engineering_team_ask_us_anything/ct4asen].)



--
This message was sent by Atlassian Jira
(v8.20.10#820010)

---------------------------------------------------------------------
To unsubscribe, e-mail: commits-unsubscribe@cassandra.apache.org
For additional commands, e-mail: commits-help@cassandra.apache.org