[
https://issues.apache.org/jira/browse/CASSANDRA-8301?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel&focusedCommentId=14227900#comment-14227900
]
Marcus Eriksson commented on CASSANDRA-8301:
--------------------------------------------
bq. Or did I get it completely wrong?
nope, it sounds about right, of course you can have bad luck and pick old-L1
sstables in L4, that would make the leveling quite bad (but it wouldn't break
anything). This is why I suggested the overlap-count trick.
Also note that cassandra checks for sstable overlaps on startup, so you can't
really break anything with this
> Create a tool that given a bunch of sstables creates a "decent" sstable
> leveling
> --------------------------------------------------------------------------------
>
> Key: CASSANDRA-8301
> URL: https://issues.apache.org/jira/browse/CASSANDRA-8301
> Project: Cassandra
> Issue Type: Improvement
> Reporter: Marcus Eriksson
>
> In old versions of cassandra (i.e. not trunk/3.0), when bootstrapping a new
> node, you will end up with a ton of files in L0 and it might be extremely
> painful to get LCS to compact into a new leveling
> We could probably exploit the fact that we have many non-overlapping sstables
> in L0, and offline-bump those sstables into higher levels. It does not need
> to be perfect, just get the majority of the data into L1+ without creating
> overlaps.
> So, suggestion is to create an offline tool that looks at the range each
> sstable covers and tries to bump it as high as possible in the leveling.
--
This message was sent by Atlassian JIRA
(v6.3.4#6332)
