Performance issue while calling Appian WEB APIs from POSTMAN

Question

In DEV environment, in our application we are using an external My SQL database as data source (which is added via Admin portal -> Datasources) and in Appian we don't have any database, but we have created CDTs according to the tables in the external database. 
 Now, when we are calling those Appian WEB APIs from POSTMAN (We are using POSTMAN so that we can test from our side whenever required and we also don't have access to the Third Party system where from actually these Appian APIs will be called in Production environement later) to fetch the data from any table or to update/insert new data into any table in that external database, we can see in the POSTMAN that the request is taking longer time than expected. GET requests are taking almost 2 seconds and for PUT/POST requests to update/insert new data it's taking 3 seconds. It is quite high regarding to the performance. 
 Is this the issue related to Indexing of the tables in the external database or we can do any indexing at Appian side in this case (although Appian internal database is not used here, we have created CDTs only)? 
 Please also let us know what are the important points we should remember for a better performance of an Appian application at the time of development. How performance tuning can be done at Appian side?

Carlos Santander · Answer

There are multiple pieces that you need to look at in your scenario, and you need to measure them separately to figure out where the bottleneck is. For instance: 
 
 If you call a Web API that returns immediately (i.e., without performing any queries or other logic), is that slow? If so, look at your connection between Postman and Appian. 
 If you run the query directly from the database, is that slow? If so, optimize the query in the database. 
 If the query isn't slow, what happens if you perform the query from Appian (i.e., test the Web API directly from Appian)? If that's slow, then look at your connection between Appian and the database. 
 
 There are other things you may look into, but this should help you get started.