PHP’s configuration can limit the amount of system memory TestRail can use on your web server. It might be needed to increase this memory limit in PHP’s configuration file in order for TestRail to process larger data sets. You can easily increase this limit by changing a setting in the PHP.ini configuration file:
memory_limit = 512M
This would increase the memory limit to 512MB. After changing the configuration settings and saving the PHP.ini file, you should also restart the web server service (either Apache or IIS) to apply the new settings.