[infinispan-dev] Lock ordering under optimistic locking

[Mircea Markus]

Hi Radim,

Definitely something to keep in mind, mind creating a jura for it?

On 9 Nov 2012, at 09:24, Radim Vansa wrote:
> Hi,
> 
> in OptimisticLockingInterceptor, the keys are ordered according to their hash. However, the hashes can still collide, which may result in a deadlock if two keys with identical hash (only 32-bit) are sorted to different order. The locks would time-out, but shouldn't we at least try to check if the keys are Comparable or let user provide some comparator class in config, and use the compare of hash only as the last resort? (and in all cases emit warning into log if the compare operation had non-strict result).
> It's a minor problem (considering other current locking issues), but I wouldn't want to investigate why such deadlock happened :)
> Btw., in OLE.visitPrepareCommand the log.tracef("Using lock reordering, order is: %s", orderedKeys); does not work, only the first key is printed out.
> 
> Radim
> 
> -----------------------------------------------------------
> Radim Vansa
> Quality Assurance Engineer
> JBoss Datagrid
> tel. +420532294559 ext. 62559
> 
> Red Hat Czech, s.r.o.
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> 
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Cheers,
-- 
Mircea Markus
Infinispan lead (www.infinispan.org)