In environments with high node counts subnet generation can be expensive to process. To make sure the application remains fast we introduced a cache for this data and by default it has a 5min expiry.
The subnet generation Generation of this cache takes part in the web request while viewing a subnet map and the cache mtime is greater than the nmisx_subnet_cache_time. In instances with large node counts this can slow down a the users web request each time the cache needs to be regenerated, if needed you can adjust increase the cache time to and lessen the impact on users.
'nmisx_subnet_cache_time' => 300
Background Subnet Caching
Recommended for larger node counts.
To perform subnet caching in the background you can use a cron job to call the opCharts CLI and perform subnet caching manually, the period in which this is run is balance between stale data and processing time taken to calculate subnets. We would recommend to run the cron job every hour. If you have implemented this method you should change nmisx_subnet_cache_time to 86400 which will stop the web thread from calculating subnets . An example cron job provided