Thread: user-defined tree methods in GIST

I need some help in building new index structure using GIST.<br /> I have to include a procedure for restructuring the
treeimmediately after i have created the index using gist. How do i do it?<br />Actually I am trying to implement the
slim-treeindex using gist. To increase the performance, a slim-down algorithm runs after creation of the slim-tree.
Wherecan i give a call to this slim-down procedure after the tree has been built using gist? <br /><br />Regards<br
/>Sharat.<br/> 

On Tue, Mar 06, 2007 at 01:50:34PM +0530, sharath kumar wrote:
> I need some help in building new index structure using GIST.
> I have to include a procedure for restructuring the tree immediately after
> i have created the index using gist. How do i do it?
> Actually I am trying to implement the slim-tree index using gist. To
> increase the performance, a slim-down algorithm runs after creation of the
> slim-tree. Where can i give a call to this slim-down procedure after the
> tree has been built using gist?

I don't quite understand what a slim-tree index is, but by my reading
it's an algorithm to make picksplit work better. I don't think you need
to touch the index machinery at all.

Also, I don't think it's a good plan to try and manipulate the index
wholesale after it's built. Once it's built, queries are going want to
use it and any changes are are going to need to be WAL logged and made
crash safe which seems quite a lot of work for something you can
probably do during picksplit.

Have a nice day,
--
Martijn van Oosterhout   <kleptog@svana.org>   http://svana.org/kleptog/
> From each according to his ability. To each according to his ability to litigate.

> I need some help in building new index structure using GIST.
>  I have to include a procedure for restructuring the tree immediately 
> after i have created the index using gist. How do i do it?

IMHO, you don't have a chance to do it without patching postgres or developing 
your own low-level function.

Try to play with SP-GiST (http://www.cs.purdue.edu/spgist/). SP-GiST is a 
modification of GiST for Space Partitioning Trees. But they patch will not work 
with 8.2 and up because of lack of concurrency. 8.2 doesn't support indexes 
without concurrency.

-- 
Teodor Sigaev                                   E-mail: teodor@sigaev.ru
  WWW: http://www.sigaev.ru/