Re: Making a tree with "millions and millions" of dynamic nodes

"John Isaacks" <jisaacks(at)yahoo(dot)com> wrote in message
news:8a9a4c2a(dot)0312101423(dot)4d31c3d4(at)posting(dot)google(dot)com(dot)(dot)(dot)
> Christian Fowler <google(at)NOSPAM(dot)gravesweeper(dot)com> wrote in message
news:<6b-dnQJnDI6YvlCiXTWc-g(at)speakeasy(dot)net>...
> > I have a VERY LARGE pile of geographic data that I am importing into a
database (db of choice is postgres,
> > though may hop to oracle if necessary). The data is strictly
hierarchical - each node has one, and only one
> > parent. The depth should not exceed 6 or 7 levels. The initial import
will have about 6 million leaves, and
> > 3 million branches.
> > For selection, it is crucial for me to get:
> >
> > 1. path generation speed
> > 2. immediate sibling speed
> > 3. children count speed
> >
>
> I don't know how high your requirement for having an SQL interface is.
> At my company we wrote a real-time database for the local number
> portability, with over 40M entries, with support for variable length
> phone numbers ( up to 10 digits ). The customer wanted the longest
> phone number match possible. example there could 1, 12, 123 in the
> database and the number 1234 would match to 123.
>
> We did it with C++ and a memory mapped file for persistence.
> We had to use a 64bit cpu and 12G of RAM.

Wow! That's only 300 bytes of RAM for every 10 digit phone number!