How much memory is being consumed? Calling ensureIndex() didn't cause a problem on my laptop, which just has 2GB of memory. Is ensureIndex() now fast for you? I'd be surprised if the query itself consumed a lot of memory.<br>
<br>Thanks,<br>Michael<br><br><div class="gmail_quote">On Sat, Apr 9, 2011 at 8:18 PM, Yihui Xie <span dir="ltr"><<a href="mailto:xieyihui@gmail.com">xieyihui@gmail.com</a>></span> wrote:<br><blockquote class="gmail_quote" style="margin: 0pt 0pt 0pt 0.8ex; border-left: 1px solid rgb(204, 204, 204); padding-left: 1ex;">
Sounds great. Thanks! It seems it's still difficult to get around the<br>
memory issue: it is almost impossible to index 1 million points on my<br>
laptop (R will not respond for several minutes if I try to brush the<br>
points).<br>
<br>
Regards,<br>
Yihui<br>
--<br>
Yihui Xie <<a href="mailto:xieyihui@gmail.com">xieyihui@gmail.com</a>><br>
Phone: 515-294-2465 Web: <a href="http://yihui.name" target="_blank">http://yihui.name</a><br>
Department of Statistics, Iowa State University<br>
2215 Snedecor Hall, Ames, IA<br>
<div><div></div><div class="h5"><br>
<br>
<br>
On Fri, Apr 8, 2011 at 7:47 AM, Michael Lawrence<br>
<<a href="mailto:lawrence.michael@gene.com">lawrence.michael@gene.com</a>> wrote:<br>
> Just a follow-up to some some concerns from the cranvas group about the poor<br>
> performance of the BSP indexing of QGraphicsScene. It looks like the index<br>
> was pretty much rewritten between Qt 4.5 (what I showed at DSC 09) and Qt<br>
> 4.6. In fact, it was being rewritten during the DSC. This has resulted in<br>
> apparently much poorer performance. It now takes 4-5 seconds to index only<br>
> 100,000 points. Don't even think about indexing a million.<br>
><br>
> Whatever they changed, it's now really slow to add a point one at a time to<br>
> the index. I think they might be sorting something each time. They're using<br>
> quick sort, but a binary tree would be a better idea for efficient updating.<br>
> Thus, I changed qtpaint to disable the index while populating the scene and<br>
> then re-enable the index after all objects have been added. This is<br>
> considerably faster. Now 100,000 points take 0.2 seconds and a million takes<br>
> 2 seconds. Nice and linear. Not as fast as before though, because there is<br>
> still a sort.<br>
><br>
> Michael<br>
><br>
><br>
><br>
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