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https://issues.apache.org/jira/browse/CASSANDRA-3710?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel&focusedCommentId=13196056#comment-13196056
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Christian Spriegel commented on CASSANDRA-3710:
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I looked into it a bit deeper and I must admit its much more complicated than I
thought. The performance penalty is not just due to the hardlinks, but due to
the memtable flushes caused by the truncate.
What we do:
We run tests from multiple threads to improve speed. Every thread in a separate
keyspace. Between tests the current keyspace is being resetted.
What happens within cassandra:
A truncate triggered from one testthread now flushes the memtables from all
other testthreads too, which causes the testthreads to fsync each other.
How I tried to resolve this:
I removed the flush+hardlink from truncate, which made it run much faster.
Unfortunetaly the commitlog still has all the data in it and I do not see a way
to drop the commitlog data withoug flushing all CFs.
Well, I guess I will make a patch for our internal testsuite. Is anybody out
there who has the same problem, but maybe a better approach?
kind regards,
Christian
> Add a configuration option to disable snapshots
> -----------------------------------------------
>
> Key: CASSANDRA-3710
> URL: https://issues.apache.org/jira/browse/CASSANDRA-3710
> Project: Cassandra
> Issue Type: New Feature
> Reporter: Brandon Williams
> Fix For: 1.0.8
>
>
> Let me first say, I hate this idea. It gives cassandra the ability to
> permanently delete data at a large scale without any means of recovery.
> However, I've seen this requested multiple times, and it is in fact useful in
> some scenarios, such as when your application is using an embedded cassandra
> instance for testing and need to truncate, which without JNA will timeout
> more often than not.
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