As is often the case - it depends.

When you define a field as Varchar you can specify both a "normal" length and a maximum length. Only the "normal" part is held with the main record and therefore if most of your records are within that length then the file size will reduce.

There is however an overhead for linking to the extended space - can't recall how long it is 20 bytes is ringing a faint bell. This topic has been discussed in the past on the Midrange list - I'd check it for you but have to run out.

Jon Paris

On Apr 4, 2018, at 10:05 AM, Jevgeni Astanovski <jevgeniast@xxxxxxxxx> wrote:

Does anyone here know if switching from CHAR to VARCHAR gives any positive
effect in terms of table size?
Explain the situation briefly.
I've got an application written on ILE/C that works with rather big table
(historical data since 1996). Currently the table size is 260M records and
PF size 170GB.
The record size is app. 650 bytes and it has some pretty large char fields,
that can be either empty or almost empty :-)

Technically I can make a new table with VARCHARs and rewrite my program to
use VARCHAR instead of CHAR, but shall it reduce the table size?

Somehow I suspect that it will only increase the table...

TIA and regards,
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