Please, please, please, please, please
Specify whether or not you mean
DB2 Symmetric Multiprocess or DB2 SMP
Or whether you mean
DB2 Multisystem
They are two, totally unrelated items.
Most people always assume someone is talking about DB2 SMP when then mean DB2 Multisystem.
DB2 Multisystem is system, not processor. But it can be useful on a single system if you want tables with multiple partitions (aka members) in it. Some people want multi partitions NOT because multi members is just how they process certain stuff but because there is a limit on the number of rows in a single partition. The history tables associated with temporal tables is IBM's latest big push for DB2 Multisystem.
The reason they call it Multisystem is you can have it store each partition on a different system. For example, if you partition by the warehouse column you can put a system at each warehouse and that partition will automatically be stored there.
If you do a
Select * from WarehouseHistory where warehouse=:MyLocalWarehouse
Then all retrievals are done locally. If you do
Select * from WarehouseHistory
Then it will process all partitions. No overrides necessary. No aliases necessary. It's all done within the database.
I just cannot get IBM to unbundle local partitioning only from multisystem partitioning.
-----Original Message-----
From: MIDRANGE-L <midrange-l-bounces@xxxxxxxxxxxxxxxxxx> On Behalf Of Holger Scherer
Sent: Friday, January 18, 2019 11:55 AM
To: Midrange Systems Technical Discussion <midrange-l@xxxxxxxxxxxxxxxxxx>
Subject: Re: Hosting sites and DB2 Multisystem
DB2Multi is not for everyone. We have customers with old RPG programs running the whole night job processing.
Single threaded. They won't gain from DB2 Multi.
Do you remember the discussions when customers went from an old box with one big CPU to a new box with four cores and double CPW, expecting to have the night jobs run faster? Nope...
-h
Am 18.01.2019 um 16:30 schrieb DrFranken <midrange@xxxxxxxxxxxx>:
Also this is a serious YMMV situation. We turned it on at one customer for the 70 day trial and after less than a week took it off! WOW! Their CPUs went right to 100% as most queries wanted tons of it. It ADDED run time in their case.
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