Connection to Oracle in a DSEE environment

sathyanveshi · Post by **sathyanveshi** » Thu Jun 09, 2005 6:04 am

Hi,

I need to extract data from a Oracle table using a Parallel Job. If I use a 4-node configuration, will the job implicitly create 4 different connections/sessions to Oracle? In that case, if I have 20 different Parallel jobs, will I end up creating 80 connections to Oracle?

Please throw some light on this...

Cheers,
Mohan

chulett · Post by **chulett** » Thu Jun 09, 2005 6:39 am

I would certainly think so.

sathyanveshi · Post by **sathyanveshi** » Thu Jun 09, 2005 9:49 pm

Fine. In that case, what if my Oracle supports only 50 sessions? How will the parallel jobs execute?

Cheers,
Mohan

ray.wurlod · Post by **ray.wurlod** » Fri Jun 10, 2005 12:24 am

Fewer than 20 at a time!

With 20 four-node jobs simultaneously you're generating over 200 processes:

20 conductor processes

80 section leader processes

80n player processes (one per stage)

Do you have more than 200 CPUs?

chulett · Post by **chulett** » Fri Jun 10, 2005 6:20 am

sathyanveshi wrote:Fine. In that case, what if my Oracle supports only 50 sessions? How will the parallel jobs execute?

Poorly.

As Ray notes, how many are you planning on running at the same time?

sathyanveshi · Post by **sathyanveshi** » Mon Jun 13, 2005 12:56 am

Hi,

I am planning to run 27 parallel jobs at a time,each containing 2 stages.

Cheers,
Mohan

ray.wurlod · Post by **ray.wurlod** » Mon Jun 13, 2005 3:52 am

That's 27 conductor processes, 108 section leader processes and 216 player processes (assuming no combination), a total of 351 processes. Do you have at least 175 CPUs on your system? It is recommended (as a rule of thumb) not to use more than two processes per CPU in PX jobs.

Can you find an approach that does not run all 27 jobs simultaneously?