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From Peter Schuller <>
Subject Re: OOM error while startup cassandra0.7.0 rc1
Date Tue, 14 Dec 2010 17:20:08 GMT
> I have 4G memory and I tried to set the binary_memtable_throughput_in_mb to
> 128M and 64M, It's still not work.
> I do not have big rows, and no row cache,use default Consistency_level...
> Any ideas?

Assuming you truly don't have large rows; what's your memtable
thresholds set to? Make sure it is not too large.

You can confirm by logging at logged GC:s (if you run with e.g.
-Xloggc:path/to/gclog) or by attaching with jconsole, what your actual
heap usage is. if it is far below your maximum heap size and suddenly
get the OOM that indicates there is a huge allocation being attempted.
If not, that indicates you're actually using a lot of heap for real,
relative to maximum heap size, and you need to adjust memtable
thresholds/row cache/etc that are expected to and do consume memory.

Note that during log reply writes will tend to happen pretty fast, so
if you do have a condition whereby you can't sustain a memtable being
flushed while another one is significantly filling you may be
triggering this deterministically on start-up but not normally during
normal operation.

/ Peter Schuller

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