Re: DDS variable length field

Charles

I believe that reading just the varying length field always requires 2 IOs if allocated = 0 - there is a location value in the main space that tells data management where in the aux space the data is.

If the data is within the allocated, then there's only one IO, as you said.

Vern

On 7/20/2012 11:53 AM, Charles Wilt wrote:

Barb's right...

But note you're not defining a minimum, the parm to VARLEN defines an
allocated size.

With a default of zero, anything written to the field will be stored
in the table's overflow area. The effect of that is to require 2 disk
I/Os for every access whenever you are touching both the varibale
length field and one or more of the other fields.

In general, when dealing with variable length fields on the IBM i,
it's best to allocate enough space so that 80% or more of your records
fit in the standard record area so that the data will be available
with a single I/O.

HTH,
Charles

On Fri, Jul 20, 2012 at 12:48 PM, Barbara Morris <bmorris@xxxxxxxxxx> wrote:

On 2012/7/20 12:42 PM, Stone, Joel wrote:

I would like to describe a variable length field with a minimum of zero length.

Just remove the parameter from the VARLEN keyword. It defaults to zero.

TEXTDATA 1000 COLHDG('MEMO TEXT')
VARLEN
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