Is there a rule of thumb that one should follow for determining the number sessions that should be set for a load or fexp jobs?
Suppose if my system is a 4 node system with 40amps/node , what would be the best practice?
The calculation that is often used in TASM (TDWM, workload management) is:
If number of AMPs <= 20, then use 1 per AMP.
If number of AMP > 20, then use 20 + (#AMPS/20)
But that number can change based on the size of the job (amount of data to be loaded):
The above calculations are for "medium" jobs.
For "Large" jobs, multiply the session number for "medium" by 1.50.
For "small" jobs, multiple the session number for "medium" by .50.
Better yet, let WLM manage the number of sessions and only change the ones that really need exceptions via WLM rules.
Thank you... Todd and Steve..
In our Tasm the no of session set for for default,large and small fexp jobs have been set to 4 ,4 & 2 respectively..
TASM will not auto calculate the no of sessions unless we put in the no of sessions . is my understanding correct?. Given Steve's formula it looks like i will definitly have to increase a TASM session limits to a higher number.. If a user uses a queryband utilitiy session to small for loading a large file then the no of sessions allocated would be only 2 in our case and performance would be low.
Steve's comment related to LOAD sessions. For EXPORT, the defaults (4, 4, 2) are generally fine. I would not change them.
Not sure what you mean by "not auto calculating". The WLM defaults are defined when the system is initialized. Load utilities default to use as many sessions as possible (and WLM controls the upper limit).
i thought the general calculation applies to the FEXP as well... Just wanted to understand if i have 2 seperate System across continents and if a Business( based in Aus ) is trying to pull medium volume of data from a TD system based out of UK, dont you think the no of sessions defined ( 4,4,2) will slow the data movement..
Just trying to see how i can accomodate such situations...