<html><body style="word-wrap: break-word; -webkit-nbsp-mode: space; -webkit-line-break: after-white-space; "><br><div><div>On 3 Apr 2009, at 20:33, Mircea Markus wrote:</div><br class="Apple-interchange-newline"><blockquote type="cite"><div>Hi,<br><br>Here are two optimizations that can be implemented in our 2PC model:<br>1) if there are only two members int the cluster use an 1PC (or if you only replicate to one buddy, like in buddy replication). If the 1st phase fails remotely, then also rollback locally. This would reduce one network roundtrip.</div></blockquote><div><br></div><div>Interesting. I assume with BR you mean DIST where a key is mapped on to 1 other peer - Infinispan won't support BR as in JBC. ;-)</div><div><br></div><div>While this is an interesting thought, it does raise the potential for race conditions - since this decision will have to be taken in the TxInterceptor in the beforeCompletion phase of a transaction, and by the time the call gets to the interceptor for replication, the topology may have changed such that you need to replicate to 2 instead of 1 other peer. Which would mean a 2PC again. So it does need some thought.</div><br><blockquote type="cite"><div>2) when asked to prepare, a participant might return a value indicating that no changes were made (read-only participant), so this one won't need an commit message, so less roundtrip.</div></blockquote><div><br></div><div>No, prepares only contain modifications. Read commands don't get added to a prepare, and if a prepare doesn't contain any writes, it isn't broadcast economising on the network call.</div><br><blockquote type="cite"><div><br>Wdyt?<br><br>Cheers,<br>Mircea<br>_______________________________________________<br>infinispan-dev mailing list<br><a href="mailto:infinispan-dev@lists.jboss.org">infinispan-dev@lists.jboss.org</a><br>https://lists.jboss.org/mailman/listinfo/infinispan-dev<br></div></blockquote></div><br><div apple-content-edited="true"> <span class="Apple-style-span" style="border-collapse: separate; color: rgb(0, 0, 0); font-family: Helvetica; font-size: 12px; font-style: normal; font-variant: normal; font-weight: normal; letter-spacing: normal; line-height: normal; orphans: 2; text-align: auto; text-indent: 0px; text-transform: none; white-space: normal; widows: 2; word-spacing: 0px; -webkit-border-infinispantal-spacing: 0px; -webkit-border-vertical-spacing: 0px; -webkit-text-decorations-in-effect: none; -webkit-text-size-adjust: auto; -webkit-text-stroke-width: 0; "><div style="word-wrap: break-word; -webkit-nbsp-mode: space; -webkit-line-break: after-white-space; "><span class="Apple-style-span" style="border-collapse: separate; color: rgb(0, 0, 0); font-family: Helvetica; font-size: 12px; font-style: normal; font-variant: normal; font-weight: normal; letter-spacing: normal; line-height: normal; orphans: 2; text-indent: 0px; text-transform: none; white-space: normal; widows: 2; word-spacing: 0px; -webkit-border-infinispantal-spacing: 0px; -webkit-border-vertical-spacing: 0px; -webkit-text-decorations-in-effect: none; -webkit-text-size-adjust: auto; -webkit-text-stroke-width: 0px; "><div style="word-wrap: break-word; -webkit-nbsp-mode: space; -webkit-line-break: after-white-space; "><div>--</div><div>Manik Surtani</div><div>Lead, JBoss Cache</div><div><a href="http://www.jbosscache.org">http://www.jbosscache.org</a><br><a href="mailto:manik@jboss.org" target="_blank">manik@jboss.org</a></div><div><br></div></div></span><br class="Apple-interchange-newline"></div></span><br class="Apple-interchange-newline"> </div><br></body></html>