incubator-cassandra-user mailing list archives

Site index · List index
Message view « Date » · « Thread »
Top « Date » · « Thread »
From Jonathan Ellis <jbel...@gmail.com>
Subject Re: commit logs are not deleted
Date Fri, 25 Sep 2009 00:22:49 GMT
When all the data from a given commit log segment has been flushed as
sstables, that segment can be deleted.  So if you do a bunch of
inserts and then stop, it's normal to have some commitlogs around
indefinitely.  All CFs are flushed on server restart, and the log
segments can then be removed, or you can add a periodic flush to the
CF definition so it will flush even when there has not been any extra
activity.

(This last part doesn't quite work as designed right now, but we're
working on a fix: https://issues.apache.org/jira/browse/CASSANDRA-455)

-Jonathan

On Thu, Sep 24, 2009 at 2:28 PM, Igor Katkov <ikatkov@gmail.com> wrote:
> Hi,
>
> I'm using Cassandra 0.4.0 rc2
>
> I can't make Cassandra to wipe commit logs. They just keep
> accumulating, no mater what settings I play with in the config file.
>
> I insert 200ooo keys. 1 CF, one column, value is 170kb, single Cassandra node.
> MemtableSizeInMB =32
> MemtableObjectCountInMillions = 0.1
>
> What do I do wrong?
>
> Please correct me if I misunderstood how things work:
>
> as soon as I insert a key-column-value, it gets written to memory, as
> soon as [data size or # of object] (see the settings above) are
> reached mem gets flushed to a commit log file. The very fact that I
> have growing number of commit logs files tells me that this flushing
> does happen.
>
> Now, commit logs records has to be transferred to the data and index
> files, I'm sure it happens as well, since my data folder is also
> growing, I see a lot of *.db files there.
> According to
> http://perspectives.mvdirona.com/2009/02/07/FacebookCassandraArchitectureAndDesign.aspx
> commit logs has to be wiped as soon as  all its column families pushed to disk.
> This thing does NOT happen somehow, I have only one column family
> defined in the conf file.
>
> Conf file - http://www.katkovonline.com/storage-conf.xml
>

Mime
View raw message