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From "Dr. Andrew Perella" <>
Subject RE: Newbie question on Cassandra mem usage
Date Fri, 26 Nov 2010 14:17:16 GMT
How can I set these per CF when I create them dynamically?

From: Aaron Morton []
Sent: 22 November 2010 21:40
Subject: Re: Newbie question on Cassandra mem usage

They are memtable_throughput_in_mb, memtable_flush_after_mins, memtable_operations_in_millions.

Under 0.7 these are per CF settings, in 0.6 these are cluster wide.

To start with try  mb one down to something like 64 or 128, ops to 0.5 and mins to 60 .

What version are you using ?


On 23 Nov, 2010,at 10:22 AM, Trung Tran <> wrote:

Is it the min_compaction_threshold and max_compaction_threshold? Do i
need to lower the memtable setting also?


On Mon, Nov 22, 2010 at 12:02 PM, Jonathan Ellis <> wrote:
> Set your columnfamily thresholds lower.
> On Mon, Nov 22, 2010 at 12:45 PM, Trung Tran <> wrote:
>> Hi,
>> I have a test cluster of 3 nodes, 14Gb of mem in each node,
>> replication factor = 3. With default -Xms and Xmx, my nodes are set to
>> have max-heap-size = 7Gb. After initial load with about 200M rows
>> (write with hector default consistencylevel = quorum,) my nodes memory
>> usage are up to 13.5Gb, show a bunches of GC notifications and
>> eventually crashes with java.lang.OutOfMemoryError: Java heap space.
>> Is there any setting that can help with this scenario?
>> Thanks,
>> Trung.
> --
> Jonathan Ellis
> Project Chair, Apache Cassandra
> co-founder of Riptano, the source for professional Cassandra support

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