Re: Varying Length fields, and LikeRec

[Barbara Morris <bmorris@xxxxxxxxxx>]

Jon Paris wrote:
> 
> > For this file:
> > A          R REC
> > A            FLD1          10A
> > A            FLD2          10A         VARLEN
> > A            FLD3          10A
> 
> Just an additional comment on this file.  I believe the original poster said
> that they wanted to save space.  In the case of a 10 character field you
> certainly won't save anything - but even if FLD2 were 1,000 bytes long, if
> the DDS is coded in this way you would _not_ save space.  In order to save
> space you must specify the optional length parameter. e.g.
> 

Jon, I think the default is one or maybe zero, giving poorest
performance but best space-saving.  I just did a little test with four
files each having two 1000A VARLEN fields.  I wrote 1000 records with
the same value for both fields, with data lengths of 0, 1, 10 and 1000.

This table shows the file sizes for each data-length/VARLEN combination
in my little test.

   varlen       |    0    |    1    |   10    |  1000   |
   -------------+---------+---------+---------+---------+
   VARLEN       |   45056 |   61440 |  110592 | 3190784 |
   VARLEN(1)    |   61440 |   61440 |   94208 | 3207168 |
   VARLEN(10)   |   77824 |   77824 |   77824 | 3223552 |
   VARLEN(1000) | 2183168 | 2183168 | 2183168 | 2183168 |