cassandra-commits mailing list archives

Site index · List index
Message view « Date » · « Thread »
Top « Date » · « Thread »
From "Ravi Prasad (JIRA)" <j...@apache.org>
Subject [jira] [Commented] (CASSANDRA-5371) Perform size-tiered compactions in L0 ("hybrid compaction")
Date Sat, 25 Jan 2014 03:20:41 GMT

    [ https://issues.apache.org/jira/browse/CASSANDRA-5371?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel&focusedCommentId=13881634#comment-13881634
] 

Ravi Prasad commented on CASSANDRA-5371:
----------------------------------------

+1 on [~br1985 ] comment. 
Even during dead node replace (using replace_address), streaming puts all sstables in L0.
2.0.x switches to STCS, in doing so, also creates larger sstables, which means more free disk
space to be left, in order for them to be compacted later into higher levels. LCS is known
to lower the amount of free disk space (headroom) needed for compaction. this is no more true
with LCS in above scenarios.
Is there a way to disable STCS fallback, please?


> Perform size-tiered compactions in L0 ("hybrid compaction")
> -----------------------------------------------------------
>
>                 Key: CASSANDRA-5371
>                 URL: https://issues.apache.org/jira/browse/CASSANDRA-5371
>             Project: Cassandra
>          Issue Type: Bug
>          Components: Core
>            Reporter: Jonathan Ellis
>            Assignee: Jonathan Ellis
>             Fix For: 2.0 beta 1
>
>         Attachments: HybridCompactionStrategy.java
>
>
> If LCS gets behind, read performance deteriorates as we have to check bloom filters on
man sstables in L0.  For wide rows, this can mean having to seek for each one since the BF
doesn't help us reject much.
> Performing size-tiered compaction in L0 will mitigate this until we can catch up on merging
it into higher levels.



--
This message was sent by Atlassian JIRA
(v6.1.5#6160)

Mime
View raw message