jbosscache-dev April 2007

On 31 Mar 2007, at 19:01, Owen Taylor wrote: > On Fri, 2007-03-16 at 01:23 +0000, Manik Surtani wrote: >> Guys, >> >> I've updated the JIRA [1] and the Javadocs on the Cache interface [2] >> to reflect the new functioning of putForExternalRead(), which I will >> implement by 2.0.0.BETA2. > > This looks like a reasonable specification to me. > >> Just like to clarify that there was also some thought around using >> READ locks for the call when pessimistic locking is used. There was >> also talk about potentially forcing READ_COMMITTED as an isolation >> level for this call if the isolation level used is anything >> stronger. Probably points I should have brought up on the call, but >> are there any thoughts around these? >> >> I'm happy with using a RL instead of a WL simply because we intend to >> only carry out this operation if the node does not exist (see first >> bullet point in the javadoc). Because of this though, I don't see >> how forcing READ_COMMITTED can benefit much, and would just add >> complexity unnecessarily. > > Because the current transaction is suspended, REPEATABLE_READ vs. > READ_COMMITTED seems pretty much irrelevant ... we aren't going > to hold any locks after the operation finishes. > > That, and the fact that the node doesn't already exists, > also means that the difference between write locks and read > locks is pretty small ... the only difference is what happens when > someone else reads between: > > - The update to the node finishes > - We release our locks > > Right? As long as data-structure integrity is preserved, using > a read lock should be OK, but I think the distinction isn't > going to matter much. > > (This is, of course, because JBossCache doesn't acquire locks > across the cluster on a write, but just lets the transaction roll > back on commit in case of conflict. > > If JBossCache did acquire cluster locks on a write, then a write > lock would be much more expensive and avoiding it a big win.) > > - Owen > This is pretty much what I thought. Not included these in the putForExternalRead() spec as a result. Cheers, -- Manik Surtani Lead, JBoss Cache JBoss, a division of Red Hat Email: manik(a)jboss.org Telephone: +44 7786 702 706 MSN: manik(a)surtani.org Yahoo/AIM/Skype: maniksurtani

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jboss-cache-testsuite-jdk16 Build Completed With Testsuite Errors

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18 years, 11 months

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jboss-cache-testsuite Build Completed With Testsuite Errors

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jboss-cache-testsuite-jdk14 Build Completed With Testsuite Errors

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jboss-cache-testsuite-140 Build Completed With Testsuite Errors

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jboss-cache-testsuite-jdk16 Build Completed With Testsuite Errors

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jbosscache-dev April 2007