And it is time again for another “stupid me”! For those unfamiliar with the concept:
Every time I do something “stupid”, which happens from time to time, I’ll do a little blog post on what happened and how I solved it. The reason for this is twofold: I’ll have a solution online I can consult if it happens again and other people can benefit from my mistakes as well. Because remember the ancient Chinese proverb: “It’s only stupid if you don’t turn it into a learning experience”. Okay, I might have made that last one up…
Some time ago, I had developed an SSIS package which made a part of a much larger project. The package loaded some reference data needed in the data warehouse to a table. Nothing fancy, just a straight load. I had deployed the package to the development server, tested it there and after everything seemed OK, I deployed the package to the user acceptance environment (UAT).
I needed to run this package so an initial load of the table could be done. I didn’t need to run the entire ETL, just the package, so I logged into the SSIS service and I execute the package. I checked the table and … it was empty. Strange. I checked the log files and I saw the package indeed transferred the correct number of rows. Double strange. As I implement best practices in my SSIS packages, I have indirect package configuration set up. Basically this means I have an environment variable on each machine telling my SSIS packages where the package can find the server and database with the configuration tables. The package uses these configuration tables to configure variables, connection strings et cetera inside the package. So I checked the environment variable and the configurations on the UAT server. Everything was fine. Triple strange. Then I checked the table on the development server. Suddenly, the number of rows had doubled! This means I was updating the development server instead of the UAT server. (Quadruple strange?) So what happened?
The answer was right under my nose: I had log into the SSIS server of the UAT environment and I executed the package manually by right clicking it and selecting “Run Package”. What I forgot however is that this doesn’t mean the package is executed on the UAT server, but it is indeed executed on my local machine! Indeed, an SSIS package is not executed where it is saved, but on the machine that calls DTEXEC. In other words, if I have server A storing SSIS packages, but I have a SQL Server Agent job executing them on Server B, the SSIS packages are executed on Server B, not Server A. Take this into account when you want a dedicated SSIS server: you’ll need to install the SQL Server engine as well just to have SQL Server Agent.
The embarrassing part is I tell people about this a lot in the forums, but when it happened to me I completely forgot about it. I blame this on the lack of caffeine and sleep
edit: I forgot to mention it in the article, but it was my colleague Valentino who had a moment of clarity and pointed out my foolishness