On Tuesday 12 May 2009 21:26:53 Ximin Luo wrote: > Matthew Toseland wrote: > > Is it a good idea to use MD5? I guess you're using it the same way that > > XMLLibrarian does, but it may be more of a problem for your application? > > you mean collisions? with md5 the expected rate of collisions is around 1 in > 2^64, so that would give an average word length of 4 assuming 2^16 possible > letters, or word length of 8 with 2^8 possible letters... it seems ok, but > maybe sha1 is safer, then.
What about deliberate collisions? Could they cause you to use more memory or
anything like that? md5 is broken...
>
> in any case, the actual plain keyword would be stored with each index so
> collisions could be detected.
>
> > From your docs...
> > An IndexNode corresponds to an SSK subspace, it contains a filter (e.g.
bloom
> > filter) for quickly ruling out an index based on the sought keywords, and
a
> > bunch of entries, which can each either be redirects to other indexes, or
can
> > be pointers to files.
>
> what's a "subspace" - the entire first "directory" of an SSK,
Yes.
> or any
> subdirectory at any level? (i'm not familiar with the terminology here,
sorry)
> an IndexTree is the former; an IndexNode is the latter.
>
> yes, entries can be redirects to other indexes, or point to files that
contain
> the actual index data = {(keyword, freenetURI that matches it, other
relevant
> information)*}. is this what you meant by files? they *don't* point to
> non-index files of content.
Hmmm, ok.
>
> > What does it mean to inflate or deflate the index?
>
> inflate = REQ the relevant data from freenet, and use it to build internal
data
> structure
>
> deflate = INS the internal data structure into freenet. for the
SSKSerialiser,
> SSK/USKs can't be partially updated without updating the whole subspace, (or
so
> i thought), which is why token-deflate throws UnsupportedOperationException.
Ok.
>
> (one way of storing it which would allow token-deflate would be having each
> indexnode as a CHK, then you'd only have to INS an updated node and all its
> parents up to the root, but i chose not to do this as CHKs have a higher
limit
> for being turned into a splitfile. was this the right decision?)
Or you could store them as separate SSKs, but I wouldn't recommend it. SSKs
can have any name after the slash. But inserting it all at once adds
redundancy etc, it's generally a good idea.
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