Re: Justa note of thanks

[vhamberg@xxxxxxxxx]

The overhead you mention when the field's contents
exceed the allocated (fixed) length is an I/O cost,
since the extra characters are stored in a different
segment on DASD.

This can have a great impact on SQL tables created in an
ad hoc basis - the default fixed length for columns
created in SQL, BTW, is 0, so ALL data has to be read
from the auxiliary space, and that's a record-by-record
thing. Not all records point to the same auxiliary
space. An index to the aux space address, as well as an
offset in the auxiliary space are part of each record
when there are varying length fields.

-snip-

> As to DASD - yes you can save space but there is some overhead whenever the
> actual content exceeds to "in record" size.  Don't forget as well that while
> you save DASD there is some CPU cost (although most of us have plenty of
> that to spare most times) since the database has to "stretch" the field out
> to its full size before handing it over to the program.

-snip-