<html><head><meta http-equiv="Content-Type" content="text/html charset=windows-1252"></head><body style="word-wrap: break-word; -webkit-nbsp-mode: space; -webkit-line-break: after-white-space;"><br><div><div>On 10 Oct 2014, at 18:06, Dan Berindei <<a href="mailto:dan.berindei@gmail.com">dan.berindei@gmail.com</a>> wrote:</div><br class="Apple-interchange-newline"><blockquote type="cite"><div style="font-family: Helvetica; font-size: 12px; font-style: normal; font-variant: normal; font-weight: normal; letter-spacing: normal; line-height: normal; orphans: auto; text-align: start; text-indent: 0px; text-transform: none; white-space: normal; widows: auto; word-spacing: 0px; -webkit-text-stroke-width: 0px;"><br class="Apple-interchange-newline">The biggest downside I see is that it would be horribly slow if the cache store doesn't support efficient iteration of a single segment. So we might want to implement a full retry strategy as well, if some cache stores can't support that.</div><br class="Apple-interchange-newline"></blockquote></div><br><div>My understanding from a discussion with Pedro (in a hard, cold and sinister place but that’s another story) is that *today* M/R is kinda horrible for global cache stores anyways that have to do the key per node filtering dance anyways. So it’s not significantly worse.</div><div>Plus I said we should do work per segment but in reality if you send 5 Map segment work to the same node, you can optimize and do a single loop only making it feel like they are separated work.</div></body></html>