Re: Calculating Extents

Posted in 1992

David Cortesi — 23 Dec 92 20:52:18 GMT — source: Informix-list mailing list archive (1991-1998)

In article <1992Dec23.170729.20715@informix.com> davek@informix.com (David Kosenko) writes: >Naomi Walker asked: >> >>Can someone please tell me a reliable way to calculate extents >>on tables with TEXT BLOBS? I've tried using the formula in >>the book, but that doesnt work well... > >>How do you calculate extents on varchars? > >...[good suggestions omitted]... The rest of the calculation >is the same as in the book. Could you guys be more explicit about what "book" you mean? Because in The Informix Guide to SQL:Tutorial, Chapter 10, we tried hard to produce accurate estimation formulas. And that chapter definitely distinguishes between the case of varchar and non-varchar rows. Check the headings "Estimating Fixed-Length Rows," "Estimating Variable-Length Rows," "Estimating Index Pages," and others. I'm sure these formulas could be made more accurate. Please post corrections or comments here, and/or email them to "doc@informix.com" Thanks. Dave Cortesi