From our experience, lag (time delay) with calculations was caused mostly with so called "expensive" calculations, which were configured with unnecessary either repeated functions or calculated too frequently something that should be calculated, for example, on daily basis.
To find out if your analysis in AF are as such or what else can cause delay in calculations, you would need to use analysis tool (PI Analysis Service 2.9 at least) and you can refer to this post for more answers Troubleshooting PI Analysis Service Performance Issues: High Latency .
Best of luck
As Marija Markovic mentioned please go through Nitin Agarwal blog. I would also recommend @Sebastien Raposo post in AF analysis Trigger not working - PI Points . Analysis 2.9 or above has better evaluation features which reduces the time lag.
To identify root cause you can set up performance monitoring points
1) AF Values Written
3) Events Processed
4) Analysis in Error
5) Evaluation Error Count
6) Memory Utilization
7) CPU utilization ( Analysis Processor Time and Total Processor Time)
After setting all performance counters, Export all analysis from AF and identify all trigger based calculations and Period calculations. Trigger based calculations sometimes receives data more frequently than processing time which delays calculations. e.g. receiving data every 1 sec and calculating TagAvg or TagMin (*-1d or *-7d etc) which have an impact on calculation time. If you are running on old AF analysis version i would recommend AF 2017 R2 and above for better threading features at the same time would recommend to analysis your calculations involving multiple days with summary. If you can move expensive summary calculations from trigger based to period it will improve processing time. You can test the same in test region before and after the change using above performance counters.
Lal Babu Shaik
Since you know which specific analyses are lagging, can you share the configuration of one of these analyses here? We would need the full configuration as well as the scheduling.