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From Schubert Zhang <zson...@gmail.com>
Subject Re: GC Storm
Date Sun, 18 Jul 2010 14:57:46 GMT
Agree to Peter Schuller.

On Sun, Jul 18, 2010 at 8:40 PM, Jonathan Ellis <jbellis@gmail.com> wrote:

> On Sun, Jul 18, 2010 at 2:45 AM, Schubert Zhang <zsongbo@gmail.com> wrote:
> > In a heavy inserting (many client threads), the memtable flush (generate
> new
> > sstable) is frequent (e.g. one in 30s).
>
> This is a sign you should increase your memtable thresholds, btw.  If
> you wrote out larger sstables, there would be less duplicate i/o
> reading them back in to compact them back out.
>
>
Yes, I usually set very bigger memtable size, such as 512MB or 1GB, but I
think is shoud just be a temp solution.


>  > Question:
> > (1) Can we modify the compaction policy, to compact the smaller sstables
> > with high priority? even when there is/are larger-compaction runing.
> > (2) Can we implement multi-thread compaction?
>
> Isn't (1) a subset of (2)?
>

Maybe yes, depends the implementation.


>
> There is a ticket open for (2) at
> http://issues.apache.org/jira/browse/CASSANDRA-1187
>
> --
> Jonathan Ellis
> Project Chair, Apache Cassandra
> co-founder of Riptano, the source for professional Cassandra support
> http://riptano.com
>

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