Get data from the Database - process model

Question

Hello community, 
 Could you please advise me. I am trying to figure out how handle some timeout or problem during get data from database. For the displaying partly of my interface I need to get data from the Database. This data is not mandatory only optional. Have you got any idea how handle situation when that database will be unavailable or reach timeout -to continue display data in my interface? Because now I will receive error message and all interface(application) is affected - because data is get for construct the interface. My idea was create an asynchronous sub-process for retrieving data from the database - but I was not able to find this solution in the best practices and on the other hand I was not able to create it - because to starting the process the system wait to any trigger/input. 
 Have you got experience with it? Thanks in advance, Pavol

baratc · Answer

Hi Pavol, 
 Based on my experience , im sharing the following options. Recently I tried below 3 options and option 3 helped me . 
 1) Execute the SQL in backend and verify the performance. Please create the expression rule and query the data from appian and verify the response. if the response is timing out . 
 a) Check if your querying table or view. Make sure to pass the filters (if possible pls include primary key). 
 b)If your querying view, please see whether you can fine tune the sql or if table try adding indexes/partitions (DBA can help) 
 c)if above options didn't work , create stored procedure to query the data and call the procedure from the process model using smart service or from expression rue using function. 
 Please let me know if you find any challenges. 
 thanks,barat