Use of copy Stage In PX

Sreedhar · Post by **Sreedhar** » Thu Apr 05, 2007 2:34 am

HI

I am using the copy stage in one of my job (to achieve the functionality) 4 times... does this by any chance reduce the performance of the job.

If yes what are the other stages which can be used as an alternative to the copy stage to improve the performance.

If no, does this have any other implications on the job.

vmcburney · Post by **vmcburney** » Thu Apr 05, 2007 5:02 am

If you want to use reference data more than once, or use different columns from the same table/file in more than one lookup, the copy stage is excellent for performance. The source data is converted into native parallel data just once and used in different places in the job.

ray.wurlod · Post by **ray.wurlod** » Thu Apr 05, 2007 7:46 am

Copy is the most lightweight of the stages that can do what it does.

However a fundamental rule of computer processing - irrespective of what tool or program you are using - is that every unit of work you add consumes some CPU cycles (and probably other resources too).

So, while the Copy stage itself may not consume much in the way of resources, the extra work you are doing on the three new streams may.

This is not a DataStage problem. The problem here lies between the keyboard and the chair.