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From "Russell Alexander Spitzer (JIRA)" <>
Subject [jira] [Commented] (CASSANDRA-7631) Allow Stress to write directly to SSTables
Date Thu, 31 Jul 2014 17:55:39 GMT


Russell Alexander Spitzer commented on CASSANDRA-7631:

Looks like that is as fast as I can go, CPU is pegged at max on my MBP. Let me clean up the
code and I'll get a preview up. I'm relying on CQLSSTableWriter to buffer and do the writes
which provides (3) for us but limits the program to 1 CQLSSTableWriter per process since it
is not thread-safe.

I think (4) and (5) could be very helpful though to giving that code an easier job.

(2) There is much bad argument parsing I still need to add. 

I'm trying to track down one bug at the moment then i'll post a preliminary branch. 

> Allow Stress to write directly to SSTables
> ------------------------------------------
>                 Key: CASSANDRA-7631
>                 URL:
>             Project: Cassandra
>          Issue Type: Improvement
>          Components: Tools
>            Reporter: Russell Alexander Spitzer
>            Assignee: Russell Alexander Spitzer
> One common difficulty with benchmarking machines is the amount of time it takes to initially
load data. For machines with a large amount of ram this becomes especially onerous because
a very large amount of data needs to be placed on the machine before page-cache can be circumvented.

> To remedy this I suggest we add a top level flag to Cassandra-Stress which would cause
the tool to write directly to sstables rather than actually performing CQL inserts. Internally
this would use CQLSStable writer to write directly to sstables while skipping any keys which
are not owned by the node stress is running on. The same stress command run on each node in
the cluster would then write unique sstables only containing data which that node is responsible
for. Following this no further network IO would be required to distribute data as it would
all already be correctly in place.

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