
Ask HN: What Is the Etymology of “Fractal Tree Index”? - postila
[Sorry I tried many ways but cannot find out how to submit my question to &quot;Ask HN&quot; section. Help is appreciated]<p>Why Fractal Trees are called so? Is there any sense in this name?
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dalke
Start with Google Scholar,
[https://scholar.google.se/scholar?q=%22Fractal+Tree+index%22...](https://scholar.google.se/scholar?q=%22Fractal+Tree+index%22&btnG=&hl=sv&as_sdt=0%2C5)
.

The top hit is the 2012 Usenix paper
[https://www.usenix.org/system/files/conference/hotstorage12/...](https://www.usenix.org/system/files/conference/hotstorage12/hotstorage12-final52.pdf)
, which has a section named "Fractal Tree indexes", and the following text:

> TokuFS uses Fractal Tree® indexes, which are sometimes called streaming
> B-trees [1].

> The Fractal Tree index is based on ideas from the buffered repository tree
> [6] and extended by [1] to provide cache-oblivious results.

Where [1] is 'Cache-oblivious streaming B-trees. In SPAA (2007), pp. 81–92.',
with many authors shared with this paper. The paper is at
[http://supertech.csail.mit.edu/papers/sbtree.pdf](http://supertech.csail.mit.edu/papers/sbtree.pdf)
and does not use the term 'fractal'. It does use the term 'growth factor',
which sounds similar to fractal, and 'recursive subtrees' looks like a common
fractal construction.

The ® in the Usenix paper suggests doing a trademark search as USPTO, yielding
[http://tmsearch.uspto.gov/bin/showfield?f=doc&state=4807:4uh...](http://tmsearch.uspto.gov/bin/showfield?f=doc&state=4807:4uhno.2.1)
:

> FRACTAL TREE

> Goods and Services ... Computer hardware and software used in connection
> with databases and file systems, namely, database processing software, file
> system software, database operative software, disk performance logic
> capabilities software, and hardware and software that improves and increases
> efficiency using cache-oblivious algorithms and data structures, and data
> layout and organization on storage media. FIRST USE: 20090410. FIRST USE IN
> COMMERCE: 20090410

This was filed December 12, 2007, published for opposition December 9, 2008,
and registered April 27, 2010. The owners is Tokutek, Inc.

My guess is that it was chosen for marketing purposes as a cool name, and
because it alludes to the recursive nature of the data structure.

~~~
postila
Thank you for this research.

Reading about it and listening a talk from Percona's employees, I had similar
thoughts, that the reasons for such name are just marketing-related. Actually,
any traditional tree structure can be considered as recursive. So this name is
just a trick.

Thanks.

~~~
dalke
As a caveat, I've never heard of this term before so may be wrong. I'm more
pointing out the tools available, which I've used for similar sorts of
analysis for other works and giving you a quick independent analysis.

Regarding your phrase "just a trick". In general, if you see a trademark then
it's a "trick", as in a 'gimmick .. or device used to attain some end'.
[https://en.wiktionary.org/wiki/gimmick#Noun](https://en.wiktionary.org/wiki/gimmick#Noun)
.

But 'trick' also has the negative meaning 'Something designed to fool or
swindle', (
[https://en.wiktionary.org/wiki/trick#Noun](https://en.wiktionary.org/wiki/trick#Noun)
) which is not the case here.

Personally, I would be happier with the term "just marketing", since a point
of trademarks is to be distinguishable in the market, and because that phrase
is a closer fit to the negative connotation I think you want to portray.

