Resources exceeded error using Datamart

[DataSkills]

Hello, 

We are working on a project to redo all the reports for an area. The current reports all use import queries and run with zero issues. However, the way we set up the original reports is that each one connects to the database and has it's own dataset, which is a pain to manage (any change requires changes to multiple datasets).

For the new project, we have elected to use a Datamart and the intention is to connect the reports directly to the datamart (which in effect means we are connected to the datamart's dataset). So far, this MOSTLY works 100%. But once or twice per day, we get messages about resources being exceeded. When we try again later, the report renders without an issue. 

The datamart is small, the number of measures is not significant and so I cannot work out what might cause this to happen. 

Turning on the performance analyser for the report in the desktop app shows some visuals are taking what seem to me to be a long time. 

We are enjoying the benefits of using the datamart, but these performance issues are making us wonder if we should rather go with a shared dataset and use import mode to overcome these challenges. However, since our model is actually very small, I feel like we are missing something in terms of our setup. 

Any suggestions gladly welcomed. 

Thanks