When loading (importing) data into the platform it is highly recommended to use the ImportSet API, if the import has to be triggered by a 3rd party system.
By doing so you, you need to configure "REST Insert Multiple" and there you have the option (besides other settings) to choose for the attribute "Transformation" between "synchronous or asynchronous":
So what is the difference? Importing and loading into the target table is a two step approach:
1. Import of raw data into your import set (staging table)
2. Transform and load (update or insert) into the target
If you choose synchronous, this will be done right after one another, so step 1 and step 2 without a break. That means, if your 3rd party system sends a POST request to ServiceNow, the request will only return after the import AND transform is completed! Now imagine you wanna load 5000 records at once (not even considering that the 3rd party systems sends you 100 such requests one after another) and consider how long the transformation might take? If the import and transformation takes too long, the request will time out and your external system gets an error.
The timeout for incoming REST requests is a system setting that can be changed, but I would not recommend that.
Better option is to go "asynch". Here the raw data is simply loaded and the request returns immediately after the import completes. And short time later the transformation will take place once the system has resources available (only two transform jobs can run simultaneously on a server node).
Please consider this when designing your data loads.
If this was helpful, please mark as such and/or leave a comment, I am happy to discuss further.
