Subject Re: [IB-Architect] trouble with sweep
Author Pavel Cisar

From my POV, the GC thread is poorly designed - badly chosen trade off.
Transaction may win a spared page write _only_ when row is accessed for
read, but for significantly bigger chance that chain would span to other
pages so next transactions would be hit not just chain traversal, but
also by more page reads. At the end, all users that would access the row
are hit harder than one poor reader that would get nailed to GC.

Although it would be nice to implement the approach used in
Netfrastructure, I don't see it doable right now (after all, we still
haven't a resolution for CS vs. SS war :). If we can't find a solution
with separate GC thread, we may revive the old method without it. Do
anyone (ex-Borlanders) have some data about average performance hit for
GC performed by old approach, and a comparison with v6 GC thread ? What
Charlie expected from new method ? If not, we can try to measure from
tests against CS.

Best regards
Pavel Cisar
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