Hi,
Just an other information about VARLEN.
When specifying VARLEN without a numeric values. The complete data is stored
in a separate space the so called overflow area. The VARLEN field contains
only the address of the overflow area. When accessint the data, they must be
first resolved, i.e. the overflow area must be searched. Also all CLOB
fields are stored in this overflow area. Searching the overflow area may
take a lot of time (compared to the execution time of the query).
When defining VARLEN(numValue). All varying textes that are shorter than the
specifed numeric value are stored directly in the table. Only longer textes
get stored in the overflow area. To get the best performance the numeric
value should be defined so that around 90% of all textes can be stored
directly in the table.
Mit freundlichen Grüßen / Best regards
Birgitta Hauser
"Shoot for the moon, even if you miss, you'll land among the stars." (Les
Brown)
"If you think education is expensive, try ignorance." (Derek Bok)
"What is worse than training your staff and losing them? Not training them
and keeping them!"
-----Ursprüngliche Nachricht-----
Von: rpg400-l-bounces@xxxxxxxxxxxx [mailto:rpg400-l-bounces@xxxxxxxxxxxx] Im
Auftrag von Jon Paris
Gesendet: Thursday, August 09, 2007 18:33
An: rpg400-l@xxxxxxxxxxxx
Betreff: Re: Database design question
NOTE 32000A COLHDG('Note') VARLEN
I would change this line to say (for example) VARLEN(1000) Nathan. That
assumes that 1,000 characters encompasses the majority of cases but
sometimes you need to go to 32K.
This gives you a better balance between performance and storage usage.
Jon Paris
Partner400
www.Partner400.com
midrange.com
