[ 
https://issues.apache.org/jira/browse/CASSANDRA-9560?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel&focusedCommentId=14578864#comment-14578864
 ] 

Fred commented on CASSANDRA-9560:
---------------------------------

Thx, that's great. 
FYI I used cassandra-cli and thrift to update the keyspace for durable writes. 
It's strange because when you describe the keyspace from cassandra-cli it looks 
like durable_writes are disabled but I've got confused when I saw alot of disk 
i/o on commitlog files despite setting durable_writes to false.
Would be great with a patch if that's possible.

> Changing durable_writes on a keyspace is only applied after restart of node
> ---------------------------------------------------------------------------
>
>                 Key: CASSANDRA-9560
>                 URL: https://issues.apache.org/jira/browse/CASSANDRA-9560
>             Project: Cassandra
>          Issue Type: Bug
>          Components: Core
>         Environment: Single node
>            Reporter: Fred
>             Fix For: 2.1.x
>
>
> When mutations for a column family is about to be applied, the cached 
> instance of the keyspace metadata is read. But the schema mutation for 
> durable_writes hasn't been applied to this cached instance.
> I'm not too familiar with the codebase but after some debugging (2.1.3), it's 
> somehow related to:
> {code:title=org.apache.cassandra.db.Mutation.java|borderStyle=solid}
> public void apply()
> {
>    Keyspace ks = Keyspace.open(keyspaceName);
>     ks.apply(this, ks.metadata.durableWrites);
> }
> {code}
> Where a cached instance of the keyspace is opened but it's metadata hasn't 
> been updated with the earlier applied durable_writes mutation, since it seems 
> that the cached keyspace instance is lazily build at startup but after that, 
> never updated. I'm also a little bit concerned if other values in the cached 
> keyspace instance suffers from the same issue, e.g. replication_factor... 
> I've seen the same issue in 2.1.5 and the only way to resolve this issue is 
> to restart the node to let the keyspace instance cache reload from disk.



--
This message was sent by Atlassian JIRA
(v6.3.4#6332)

Reply via email to