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TeraData Enterprise Stage Problem

Posted: Tue Mar 04, 2008 1:26 am
by vrishabhsagar
Hi,

I am getting the following warning when using Teradata Stages in my job.

Teradata_Step2,7: Insufficient blocks for partition 7. Reading suppressed.

The result set however is not affected at all. Does anybody have an idea about this strange warning?

Thanks!!

Posted: Tue Mar 04, 2008 2:07 am
by ray.wurlod
Can you please post the entire error message, so we can discern whether these are Teradata blocks or DataStage transport blocks?

Posted: Tue Mar 04, 2008 2:40 am
by JoshGeorge
Try minimizing repartitioning by increasing the number of sessions.

Posted: Tue Mar 04, 2008 3:11 am
by gge
How many nodes do you have ?

How many lignes in your treatment ?

Cordially, Gabriel Georgin.

Posted: Tue Mar 04, 2008 6:12 am
by throbinson
You've got at 7 partitions and only 6 rows of data. This is not configurable by the Configuration file. It is RequestedSessions and SessionsPerPlayer defined to the Teradata Enterprise Stage. If you are not explicitly setting these variables in the Additional connections property then you are getting the default of 2 SessionsPerPlayer. This means you have 14 AMPS in the source Teradata Database. 14/2=7. The Teradata Enterprise Stage is starting 7 processes/sessions and there is only data for 6. One gets no rows and warns you about it. This would be one of the extremely few times I would suggest demoting the warning to informational via a MsgHandler.

Posted: Thu Jul 31, 2008 5:28 pm
by bcarlson
We are getting the same issue. The query we are running should only be returning 1 record. This works fine, as vrishabhsagar said the result set is accurate.

I tried to limit the number of sessions by setting the options to

requestedsessions=1

... and no other parms, but this caused it to fail with the following error:
td_srce_process_dt: A maximum of 1 sessions per player (the number requested overall) may be requested, but the number requested was 2. [terareadop.C:408]
I am not sure what this error is. What is the lowest setting you can use (between requested sessions and sessions per player)?

Thanks!

Brad

ps. I am not really try ing hijack someone elses posting, this just seemed like it was directly related to the original.

Posted: Fri Aug 01, 2008 5:47 am
by throbinson
Looks like you can't do that. RequestedSessions most probably works in concert with SessionsPerPlayer which must work in concert with the Configuration file. The SessionsPerPlayer default is two. I'll bet you can't request 1 session and try to use the default SessionsPerPlayer default of 2. That's a contradiction.
The Enterprise Stage will create OS processes, not based on the number of nodes in the Configuration file, rather on the two settings. Usually you'll want the Teradata Enterprise Stage Players to match the number of nodes the rest of the job will be using. Having determined the number of players you want, you can then tune the number of Sessions per those players that you want Teradata to fire up. This is based on the size and sheer majesty of your Teradata database.

Here in St. Louis, we limit the number of sessions to 8 regardless of the number of nodes that the job uses. The reasoning being that any more than 8 will most likely go idle as Teradata fetches rows via the 8 sessions. It's quick and powerful enough to never need more than 8. The other thing we standardize on is Configuration files. We have 1,2,4,8 node configuration files. Therefore, we make the SessionsPerPlayer 8,4,2,1 to match the Configuration files. RequestedSessions/SessionsPerPlayer= Players (nodes).
8/1=8, 8/2=4,8/4=2,8/8=1.