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From Paul Brown <paulrbr...@gmail.com>
Subject Re: cassandra instability
Date Fri, 16 Apr 2010 18:13:24 GMT

Two more things you can do:

1) If you're running the updaters in the JVM (sounded like you were doing PHP?), then be sure
that you're cleaning up the database sessions properly.  Hibernate, in particular, will keep
a lot of bookkeeping data around otherwise, and that can easily overflow your heap.

2) Use jmap to get some heap snapshots and see what the problem is ($PID is the process ID
of your Cassandra process):

jmap -histo $PID > histo-`date +%s`

With several of those and a little bash-fu, you ought to be able to see what the leak is.

-- Paul

On Apr 16, 2010, at 11:06 AM, Lee Parker wrote:

> Row caching is not turned on.
> Lee Parker
> 
> On Fri, Apr 16, 2010 at 12:58 PM, Paul Brown <paulrbrown@gmail.com> wrote:
> 
> On Apr 16, 2010, at 10:50 AM, Lee Parker wrote:
> > [...]
> > I am trying to migrate data from mysql into the cluster using the following methodology:
> > 1. get 500 rows (12 columns each) from mysql
> > 2. build a batch_mutate to insert these rows into one CF (1 row = 1 row )
> > 3. build a second batch_mutate to insert an index of those rows into a second CF
( 1 row = 1 column )
> > 4. loop around and do it again until all data has migrated.
> 
> If you have row caching turned on and are putting a lot of data in each row, you might
be causing the memory issues.  Maybe turn row caching off?
> 
> -- Paul
> 
> 


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