Re: B-Tree Levels of IDS

Assuming you have a fill factor of 100%, and the number of rows in the table is N, and the number of rows you can fit on an index page is M, you can get a good approximation by doing a ln([N/M]) (the natural log of N/M) and rounding up. Given N = 32,767 total rows, and M = 4 rows per index page, you'd have: ln (32,767/4) = ln (8191.75) ~= 9.01 levels = 10 levels. Remember that each level is exponentially larger than the previous one, so the top level has one index page, the next two, the next four, etc. Of course, it's been a REALLY long time since I've used this kind of math, so I could be wrong here, but I believe this is very close. sanjeev sagar wrote in message <717mvk$557$1@news.xmission.com>... > > > > > >I think i did not explain my Q very well. Here it is >again > >I want to know the no of btree levels in an index >even before creating table. I know how many no of >rows would be in index but i need to know no of btree >levels in an Index, before create table. > >Does it make any sense? In other words any kind of >theoretical equation? > >Thanks >Sanjeev > >---"Art S. Kagel" <kagel@bloomberg.net> wrote: >> >> Lucie Janstova wrote: >> >> > Try: >> > select * from sysindexes >> > where idxname = "my_index";>> >> This works if the statistics are updated by UPDATE >STATISTICS LOW ... or >> UPDATE STATISTICS HIGH... on the table (MEDIUM does >not update index>> statistics only distributions). >> >> > Lucy (lucie.janstova@post.cz) >> >> > sanjeev sagar wrote in message ><712vps$33r$1@news.xmission.com>... >> >> > >I am using IDS 7.30 on Solaris 2.5.1 I am having >one Q >> > > >> > >How can i find out total no of btree index >levels, if >> > >I know the total no of rows in the index? >> >> Art S. Kagel >> > >_________________________________________________________ >DO YOU YAHOO!? >Get your free @yahoo.com address at http://mail.yahoo.com >