<html><head></head><body style="word-wrap: break-word; -webkit-nbsp-mode: space; -webkit-line-break: after-white-space; "><br><div><div>On 15 Sep 2011, at 14:44, Paolo Romano wrote:</div><br class="Apple-interchange-newline"><blockquote type="cite"><span class="Apple-style-span" style="border-collapse: separate; font-family: Helvetica; font-style: normal; font-variant: normal; font-weight: normal; letter-spacing: normal; line-height: normal; orphans: 2; text-align: -webkit-auto; text-indent: 0px; text-transform: none; white-space: normal; widows: 2; word-spacing: 0px; -webkit-border-horizontal-spacing: 0px; -webkit-border-vertical-spacing: 0px; -webkit-text-decorations-in-effect: none; -webkit-text-size-adjust: auto; -webkit-text-stroke-width: 0px; font-size: medium; ">Concerning costs. For option 2), the prepare message should piggyback<span class="Apple-converted-space"> </span><br>the version identifiers of *each* data item that needs to be write-skew<span class="Apple-converted-space"> </span><br>checked...which may lead to big messages, if you needed to test a lot of<span class="Apple-converted-space"> </span><br>data items. But the ws-check is done only on the data items that are<span class="Apple-converted-space"> </span><br>both read and written within the same xact. So I'd expect that normally<span class="Apple-converted-space"> </span><br>just a few keys would need to be write-skew checked (at least this would<span class="Apple-converted-space"> </span><br>be the case for the wide majority of DBMS/STM benchmarks I've been using<span class="Apple-converted-space"> </span><br>so far). Therefore I would not be too concerned with this issue.</span></blockquote><br></div><div>True, but if a vector clock is used as the underlying version scheme, then the updating node would need to send across its local clock for each data item, regardless of whether a ws-check is needed for that data item or not. Correct?</div><br><div>
<span class="Apple-style-span" style="border-collapse: separate; color: rgb(0, 0, 0); font-family: Helvetica; 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-horizontal-spacing: 0px; -webkit-border-vertical-spacing: 0px; -webkit-text-decorations-in-effect: none; -webkit-text-size-adjust: auto; -webkit-text-stroke-width: 0px; font-size: medium; "><div><div>--</div><div>Manik Surtani</div><div><a href="mailto:manik@jboss.org">manik@jboss.org</a></div><div><a href="http://twitter.com/maniksurtani">twitter.com/maniksurtani</a></div><div><br></div><div>Lead, Infinispan</div><div><a href="http://www.infinispan.org">http://www.infinispan.org</a></div><div><br></div></div></span><br class="Apple-interchange-newline">
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