The main reason IBM "does it" for marketing purposes. IBM can use it as a
"feature" to attract new customers by telling them it will make DB2 easy to
use and administer.
I'm from DB2 for i5/OS world, where (from V5R2 and the introduction of
the new "SQE") statistics collection are rather simple to collect
(roughly speaking just change an OS system values to turn statistics
on/off) and other information about the use of the objects (table, view
and indexes are all objects, like everything you can manage in "AS/400)
are updated by OS itself, disregarding of sql; the job collecting
statistics runs at the lowest priority. At V5R4 there are a lot of
information about suggested indexes, sql statement executed and so on
available to "db administrator" (that usually is *system administrator*
itself ;-) that are automatically collected without the need (or
possibility) to turn them on or off.
Imo with SQE statistics collection its quite useful...
It *seems* to me that Ibm is trying to "export" some of this automatic
capabilities to other version of DB2: imvho the problem might arise when
they try to do this on "non Ibm" operating systems, as DB2 for i5/OS is
*built in* i5/OS but this is not true for other operating systems and
DB2 versions.
My two cents
Stefano P.
--
"Niuna impresa, per minima che sia,
può avere cominciamento e fine senza queste tre cose:
e cioè senza sapere, senza potere, senza con amor volere"
[Anonimo fiorentino, XIV sec.]
(togliere le "pinzillacchere" dall'indirizzo email ;-)
