removal of warning "cannot preserve partitioning"

[rameshybr]

Hi,

I am getting warning "sequential operator cannot preserve the partitioning" while running the below job at sequential stage.

The job design:


sequential file ---->tranformer stage---->lookup-1)--->odbc--->reject link
2)--->copy stage

from transformer stage we have partition as "Auto" and we are trying to clear the partition in lookup stage and in odbc.
The error is not coming.

But whehter it is a best practice to do the that and please let us knoe the disadvantage.

In every where we are using "Auto" as partition method.


Please suggest there is any other way to remove the warning.

Rd,
ramesh.

[asorrell]

Look at the Advanced tab of the stage before the sequential file. You will see that it has Preserve partitioning set to "Default (preserve)". That stage is saying "don't mess with my partitioning". However the sequential file is by its very nature, not partitioned, so it can't preserve the partitioning. Hence the warning message.

To remove it, set the "Preserve paritioning" to "Clear", which tells the subsequent stage it is "ok" to change the partitioning.

This is one of the best practice methods to resolve the issue.

[rameshybr]

Hi Andy,
Thanks for the reply.

Here one more question is whether it will degrade any performace of the job?
pls suggest.

[jerome_rajan]

No. It will not affect the performance in any way. What you encountered was just a warning telling you that no matter what 'YOU' want, the stage will partition data the way 'IT' wants. Clearing the "preserve partitioning' flag will serve only as far as eliminating the warning.