Nocontenate every load

[markp201]

Normally, noconcatenate is used override qlik default behaviour when table structures match.

Are there any issues (performance or otherwise)  with adding noconcatenate to every load even when the structures don't match?

[dplr-rn · Accepted solution]

Why do you want to do that?
I wouldnt assume there will be much of overhead as far as running the script is concerned. unless there is multicolumn synthetic keys

[markp201]

Our developer in this case is just a novice.  Its just confusing to support this because when I see noconcatenate, the first thing I look for is which table has the same structure.

[evan_kurowski]

As much as the 'auto-concatenate' feature tries to be helpful, many a development session has been blasted away as puzzled developers try to figure out "what happened to my table?!"


Such as a tricky situation like placeholders. If there's no performance hit for using NOCONCATENATE I wouldn't be too hard on them (in a defensive programming world, are they doing any harm?).

[PLACEHOLDER_FOR_TABLE_1]:
LOAD 1 AS ID AUTOGENERATE (0);
 //.....some scripting later //

[PLACEHOLDER_FOR_TABLE_2]:
LOAD 1 AS ID AUTOGENERATE (0);
 //** What happened to my second target table?!

I've had "clever" experiences where when auto-concatenate is in effect, a seeming innocuous later date change subtlely aligns two formerly disparate table structures into a unified one and results in unintended auto-concatenation never meant to be such, and becomes a big headache.

Be cautious when presented with the innocent request (many months later) for "would itttt be hard to rename this one field from [BlaBla] to [BlablaBla]?" You might be getting set-up.