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From ruslan usifov <>
Subject Re: ParNew (promotion failed)
Date Wed, 23 Mar 2011 18:18:02 GMT
2011/3/23 Narendra Sharma <>

> I think it is due to fragmentation in old gen, due to which survivor area
> cannot be moved to old gen. 300MB data size of memtable looks high for 3G
> heap. I learned that in memory overhead of memtable can be as high as 10x of
> memtable data size in memory. So either increase the heap or reduce the
> memtable thresholds further so that old gen gets freed up faster. With
> 16CFs, I would do both i.e. increase the heap to say 4GB and reduce memtable
> thresholds further.
> I think that you don't undestend me, 300MB is a summary thresholds on all
16 CF, so one memtable_threshold is about 18MB. Or all the same it is
necessary to reduce memtable_threshold?

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