[firebird-support] Index Memory Usage

[Ekundayo eday...@yahoo.com [firebird-support]]

Hi All, can anyone tell me (or point me in the direction of manuals) how i can 
calculate the amount of memory used by the indexes of a particular table? 
I have a table in which I store sha1 hashes (currently about 2 million records) 
as char(40) and its indexed, I'm wondering if the table would consume less 
memory if the hashes are stored as BIGINT
Thank you