Support Forums : DataStax

DataStax Support Forums » DataStax Community

Commit log is not sync'ng periodically and still holding the yesterday's data

(4 posts) (2 voices)

Started 6 months ago by gopia
Latest reply from Sven
This topic is resolved

Tags:

No tags yet.

gopia
Member

I am using the 1.1 datastax linux (centos) installer for the cassandra service.

The cassandra service is holding the past data and not flushing periodically even thought the commit log sync period is timed out. Please let me know any other setting are required to check.

Below are the setting i use in cassandra.yaml

commitlog_sync: periodic
commitlog_sync_period_in_ms: 10000

commitlog_segment_size_in_mb: 32

If i change the commitlog segment size to a lower value than the commit log folder size, then only the cassandra is clearing the commitlogs.

Please help me, i am not sure whether the commitlog segment size requires changes to the value.

Posted 6 months ago #
Sven
Administrator

You may be misinterpreting what commitlog_sync_period_in_ms means (please see http://wiki.apache.org/cassandra/Durability for a more detailed explanation). It only refers to the interval between fsyncs, which ensures that the data written to the commitlog is committed to disk.

A common concern is to keep the size of the commit log small, in which case you may want to consider changing the parameter commitlog_total_space_in_mb. Not sure whether that is you issue though.

Are you observing a particular issue that triggers your concern, or in other words, what problem are you trying to solve?

Posted 6 months ago #
gopia
Member

Thanks for the reply.. I am bit confused between commitlog_segment_size_in_mb and commitlog_total_space_in_mb. I changed the commitlog_total_space_in_mb value to a less value to make the updates reflect immediately on the front-end.

Posted 6 months ago #
Sven
Administrator

commitlog_segment_size_in_mb controls the size of the individual commitlog files. So I wouldn't expect that to affect what data is visible when.

When you say updates are not reflect immediately in the frontend, what exactly are you talking about? Do you have a more concrete example of what you are doing/observing?

Posted 6 months ago #

RSS feed for this topic

Reply

You must log in to post.