On 02/01/13 16:18, Tyler Hobbs wrote:
On Wed, Jan 2, 2013 at 5:28 AM, James Masson mailto:james.mas...@opigram.com>> wrote:
>
1) Hector sends a request to some node in the cluster, which will act as
the coordinator.
2) The coordinator then sends the actual read requests out to ea
On 31/12/12 18:45, Tyler Hobbs wrote:
On Mon, Dec 31, 2012 at 11:24 AM, James Masson mailto:james.mas...@opigram.com>> wrote:
Well, it turns out the Read-Request Latency graph in Ops-Center is
highly misleading.
Using jconsole, the read-latency for the column family in qu
left on my list for investigation are memtable sizes /
eviction and JNA - and trying to capture some of the requests that are
causing the spikes for further investigation.
James M
On 31/12/12 10:05, James Masson wrote:
Hi Yiming,
I've had the chance to observe what happens to cassandr
Hi Yiming,
I've had the chance to observe what happens to cassandra read response
time over time.
It starts out with fast 1ms reads, until the first compaction starts,
then the CPUs are maxed out for a period, and read latency rises to 4ms.
After compaction finishes, the system returns to 1
On 21/12/12 17:56, Yiming Sun wrote:
James, you could experiment with Row cache, with off-heap JNA cache, and
see if it helps. My own experience with row cache was not good, and the
OS cache seemed to be most useful, but in my case, our data space was
big, over 10TB. Your sequential access pa
Hi Aaron,
On 23/12/12 20:18, aaron morton wrote:
First, the non helpful advice, I strongly suggest changing the data
model so you do not have 100MB+ rows. They will make life harder.
I don't think we have 100MB+ rows. Column families, yes - but not rows.
Write request latency is about 900
(http://lmax-exchange.github.com/disruptor/) fed to do the processing work.
But this all doesn't change the fact that under this zero-cache
workload, cassandra seems to be very CPU expensive for throughput.
thanks
James M
On Fri, Dec 21, 2012 at 10:36 AM, James Masson mailto:james.mas...@
nux disk cache. 2Gb VM, 512Mb cassandra
heap - GCs are nice and quick, no JVM memory problems, used heap
oscillates between 280-350Mb.
Basically, I'm just puzzled as cassandra doesn't behave as I would
expect. Huge CPU use in cassandra for very little throughput. I'm
struggling t
Hi list-users,
We have an application that has a relatively unusual access pattern in
cassandra 1.1.6
Essentially we read an entire multi hundred megabyte column family
sequentially (little chance of a cassandra cache hit), perform some
operations on the data, and write the data back to ano
