On Saturday 02 May 2009 00:59:57 Matthew Toseland wrote: > On Saturday 02 May 2009 00:53:27 Evan Daniel wrote: > > On Fri, May 1, 2009 at 7:01 PM, Matthew Toseland > > <toad at amphibian.dyndns.org> wrote: > > > On Friday 01 May 2009 22:43:50 Robert Hailey wrote: > > >> > > >> On May 1, 2009, at 3:46 PM, Evan Daniel wrote: > > >> > > >> > Yes, that's a question worth considering. ?There are both performance > > >> > and security issues involved, I think. ?Note that the partition could > > >> > be a set of contiguous regions (allowing performance optimization > > >> > around which piece of the keyspace you send info about), but it could > > >> > just as easily be determined by a hash function instead. > > >> > > > >> > You still check the same number of filters overall -- one per peer. > > >> > The difference is that for some peers you may have a partial filter > > >> > set, and therefore sometimes check their filters, instead of deciding > > >> > you don't have the memory for that peer's filter and never checking > > >> > it. > > >> > > >> Maybe if we partition it we can also get a free datastore histogram on > > >> the stats page. > > > > > > No, we cannot divide by actual keyspace, the keys must be hashed first, or > the > > > middle bloom filter will be far too big. > > > > Well, you could partition by actual keyspace as long as the partitions > > are (approximately) equal in population rather than fraction of the > > keyspace they cover. Doing that is only mildly nontrivial, and gives > > you a histogram with variable-width bars, but still an accurate > > histogram. Each bar would cover the same area; tall and skinny near > > the node's location, wide and short away from it. > > And if the distribution was ever to change ... it's not mildly nontrivial > IMHO. > > Anyway, the first version should simply use the existing filters, to make > things easy.
Another point about this: we can send one filter at a time, we have four of them. That is easy and can be done without maintaining any additional filters. -------------- next part -------------- A non-text attachment was scrubbed... Name: signature.asc Type: application/pgp-signature Size: 835 bytes Desc: This is a digitally signed message part. URL: <https://emu.freenetproject.org/pipermail/devl/attachments/20090502/bae356e9/attachment.pgp>
