How to calculate logical file size
Hi,
I need to be able to estimate the size of a logical file (inc access path). I've tried creating this file and almost filled the machine up. This is logical has quite a lot of key fields.
Does anyone know a simple way of estimating the size (IBM has a formula in the manuals, but I can't make out what to do with it).
Thanks in advance,
Martin Gilbert.
Software/Hardware used:
Software/Hardware used:
ASKED:
February 8, 2008 10:36 AM
UPDATED:
March 14, 2010 1:08 AM
Answer Wiki:
You must be running very tight on disk space or this file is extremely large.
For an example on our system, here's what our order detail file looks like
Physical has no key fields,
164 fields and a record length of 798 characters.
Total number of records in the file 3,604,910
file size in bytes 2,952,830,976
one of our logicals over this file looks like this
we have 8 key fields over the entire file. ( No select or omits. )
The file size of this logical in bytes is 3,686,400 for a ratio of .12%
Very small compared to the physical.
Check your availablr disk space by using the command WRKSYSSTS.
in the upper right ours looks like
Auxiliary storage:
System ASP . . . . . . : 668.8 G
% system ASP used . . : 57.0926
Total . . . . . . . . : 668.8 G
Current unprotect used : 10056 M
Maximum unprotect . . : 17609 M
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Does anyone know a simple way of estimating the size (IBM has a formula in the manuals, but I can’t make out what to do with it).
Simplest way for me is to test it physically. Create the index and add 100, 5000, 10000 entries. The more increments you can use, the better your trendlines will be.
I might work the formulas if you supply key length and access path size.
Tom