Removing ports from an existing mapping - Do's and Dont's

Recently, a colleague called in for an issue that he was facing with an Informatica mapping. Let me recreate that situation here -

There is a mapping that get n ports from a source and loads m ports to a target. Standard stuff, nothing special or fishy around there. There comes a change request that says, such and such x number of columns are not required in the target, and since there would be a sure performance penalty for carrying through extra data (however small), the mapping should be changed to remove those ports from the pipeline.

What this gentleman did was to remove the connections for those ports from the source qualifier onwards. That saved him from changing and re-importing the source definition.

However, the mapping execution failed, complaining about a certain error situation. Thats when I got the call :)

whether I could discuss and fix it is something else, but what was the reason of the error - ?  

The very fact that if you are bringing in certain ports in the source qualifier, you HAVE to take them forward.  Thats a rule from informatica's side. Which means, if you are pulling up n ports from the source, you HAVE to expose all those n ports going away from the source qualifier. Or, putting it differently, in whichever way you create a set of ports in your source qualifier, all of them have to be consumed by some transformation object. Not a single one can be left unconnected, on the input side or the output side. Simple.

That was the reason, and the solution was fairly simple, to reduce his effort, either remove the ports from source qualifier as well, or just carry them forward to one transformation. and then drop them onwards.

Having said that, the very reason for which this whole change was initiated, the performance gain that would come through by not having the extra ports being carried forward, would come only when you remove the un-wanted ports from the source itself.

Moving an ecommerce site to Amazon Web Services

This is an interesting one.. There is an e-commerce startup, run by a dear friend.  One fine day we were chatting around and he mentioned challenges with his business. Challenges included performance, scaling and cost issues about his hosting services provider.

My instant reaction was, why dont you move to aws.. and it clicked just like that.. We decided that we'd start with the free tier, with his mysql server on amazon RDS and rest of app server functionality on the micro instance. All of which is within purview of the free tier.  Using Cloudfront we'd localize the static content, to add to the performance of content delivery. Not now, but eventually, we'd start using ELB - the load balancer for distributing load across the instances we would have.

With something like aws, planning all that is really really that straightforward.  You just have to be a bit more technically oriented to think in terms of these things and you are set for good.

We are already thinking about configuring autoscaling for the services, so that running on the micro instance doesnt become a bottleneck for the customers. With that we'd hope to achieve dynamic automatic scaling up and down the infrastructure.

We have already taken the first steps, and I am helping his venture migrate to AWS, one of my dream jobs, to be able to consult around migration / integration of Traditional systems to cloud based systems.