Re: b-tree keys per node
Date: 2000/03/17
Message-ID: <8au4p8$2hb8$1_at_news.cybercity.dk>#1/1
Hi Amy,
>Can anyone point me toward a discussion, online or published, on
>selecting the number of keys per node in a b-tree for optimal
>performance?
Ingres goes for default packing of 80% in btree tables (70% for leaf nodes). No idea what would be best, but this seems to work fine.
Actually this never quite gets utilised. This 80% represents (in Ingres) a maximum (initial) packing per page, and analysis shows quite a spread of keys per page, but well over half fit the choosen percentage.
More keys mean more locking conflicts but faster deletes/updates, less keys mean wasted space, and slower queries!
Take your pick.
Try http://www.altavista.com and search on something like "+btree +theory +database +index" - I got 131 web pages listed.
Regards
Andrew Wilson
BlueOffice Solutions ApS
Denmark
Received on Fri Mar 17 2000 - 00:00:00 CET