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From Jason Harvey <>
Subject Bizarre side-effect of increasing read concurrency
Date Sat, 02 Apr 2011 03:21:05 GMT
After increasing read concurrency from 8 to 64, GC mark-and-sweep was
suddenly able to reclaim much more memory than it previously did.

Previously, mark-and-sweep would run around 5.5GB, and would cut heap
usage to 4GB. Now, it still runs at 5.5GB, but it shrinks all the way
down to 2GB used. This behavior was consistent in every machine I
increased read-concurrent on.

Any thoughts on why this behavior changed? No other diagnostics
appeared to correlate to the concurrency change, besides thread count.

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