>Tore in your reply"that I always make sure that my index keys give a fixed length value"
>its mean cdx or idx size in kb. if true, how much size are recmended by you.

I am not talking about the size of an index file, but the length of the key. One example:

Index on alltrim(custname) && Can give different lengths for each cust_name, and is very DANGEROUS
Index on padr(alltrim(cust_name),16) && Safe, will always give keys of length 16