Mark, We're not seeing exactly the numbers that Mike is seeing in his tests, running with jdk 1.5 on intel macs, so we're trying to eliminate factors of difference.
Point 2 does indeed make a difference, we've seen it, and it's only fair: the single pq comparator does this branch optimization but the current patch multi-pq does not, so let's level the playing field. John's on the road with limited net connectivity, but we'll have some numbers to compare more over the weekend for sure. -jake On Thu, Oct 22, 2009 at 7:29 PM, Mark Miller <markrmil...@gmail.com> wrote: > Why? What might he find? Whats with the cryptic request? > > Why would Java 1.5 perform better than 1.6? It erases 20 and 40% gains? > > I know point 2 certainly doesn't. Cards on the table? > > John Wang wrote: > > Hey Michael: > > > > Would you mind rerunning the test you have with jdk1.5? > > > > Also, if you would, change the comparator method to avoid > > brachning for int and string comparators, e.g. > > > > > > return index.order[i.doc] - index.order[j.doc]; > > > > > > Thanks > > > > > > -John > > > > > > On Thu, Oct 22, 2009 at 2:38 AM, Michael McCandless > > <luc...@mikemccandless.com <mailto:luc...@mikemccandless.com>> wrote: > > > > On Thu, Oct 22, 2009 at 2:17 AM, John Wang <john.w...@gmail.com > > <mailto:john.w...@gmail.com>> wrote: > > > > > I have been playing with the patch, and I think I have some > > information > > > that you might like. > > > Let me spend sometime and gather some more numbers and > > update in jira. > > > > Excellent! > > > > > say bottom has ords 23, 45, 76, each corresponding to a > > string. When > > > moving to the next segment, you need to make bottom to have ords > > that can be > > > comparable to other docs in this new segment, so you would need > > to find the > > > new ords for the values in 23,45 and 76, don't you? To find it, > > assuming the > > > values are s1,s2,s3, you would do a bin. search on the new val > > array, and > > > find index for s1,s2,s3. > > > > It's that inversion (from ord->Comparable in first seg, and > > Comparable->ord in second seg) that I'm trying to avoid (w/ this new > > proposal). > > > > > Which is 3 bin searches per convert, I am not sure > > > how you can short circuit it. Are you suggesting we call > > Comparable on > > > compareBottom until some doc beats it? > > > > I'm saying on seg transition you indeed get the Comparable for > current > > bottom, but, don't attempt to invert it. Instead, as seg 2 finds a > > hit, you get that hit's Comparables and compare to bottom. If it > > beats bottom, it goes into the queue. If it does not, you use the > ord > > (in seg 2's ord space) to "learn" a bottom in the ord space of seg 2. > > > > > That would hurt performance I lot though, no? > > > > Yeah I think likely it would, since we're talking about a binary > > search on transition VS having to do possibly many > > upgrade-to-Comparable and compare-Comparabls to slowly learn the > > equivalent ord in the new segment. I was proposing it for cases > where > > inversion is very difficult. But realistically, since you must keep > > around the ful ord -> Comparable for every segment anyway (in order > to > > merge in the end), inversion shouldn't ever actually be "difficult" > -- > > it'd just be a binary search on presumably in-RAM storage. > > > > Mike > > > > --------------------------------------------------------------------- > > To unsubscribe, e-mail: java-dev-unsubscr...@lucene.apache.org > > <mailto:java-dev-unsubscr...@lucene.apache.org> > > For additional commands, e-mail: java-dev-h...@lucene.apache.org > > <mailto:java-dev-h...@lucene.apache.org> > > > > > > > -- > - Mark > > http://www.lucidimagination.com > > > > > --------------------------------------------------------------------- > To unsubscribe, e-mail: java-dev-unsubscr...@lucene.apache.org > For additional commands, e-mail: java-dev-h...@lucene.apache.org > >
