A global index has to be prefixed and range-partitioned,
so you could imagine that the list of values that defines
the ranges for each partition is equivalent to 'root block'.
e.g. if value < 46 then use partition 1, else if value < 92
then use partition 2 and so on, in just the way the
root block is simply a list of values and pointers to the
next level branch blocks.
--
Regards
Jonathan Lewis
http://www.jlcomp.demon.co.uk
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who can answer the questions, but the
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The Co-operative Oracle Users' FAQ
http://www.jlcomp.demon.co.uk/faq/ind_faq.html
"Rob Cowell" <rjc4687_at_hotmail.com> wrote in message
news:3F5622A0.3DCB20F3_at_hotmail.com...
> Can anyone point me at a description of how a global index works?
The
> concepts manual says "a global partitioned index contains
(conceptually)
> a single B*-tree with entries for all rows in all partitions. Each
index
> partition may contain keys that refer to many different partitions
or
> subpartitions in the table".
>
> I guess this means you only need one index probe to get a rowid, but
I
> don't understand how that can work when (I guess) the leaf blocks
are in
> separate partitions without some kind of master area for the branch
> blocks, or at least the root block. Can anyone point me at a good
> description.
>
> Thanks.
Received on Wed Sep 03 2003 - 13:01:29 CDT
