Thanks @Sat, my thinking was that a stalled subnet and a halted subnet are probably indistinguishable via the dashboard. But of course I can see the timestamps for the relevant data points.
Assuming this timestamp is local time for me (BST), then the flatling of transactions occurred just before 19:00 UTC, which pre-dates the execution of the proposal that halted the subnet (2024-09-15, 18:53:11 UTC).
However, I would have expected the timestamps displayed on the dashboard to be in UTC, particularly given that UTC is used in numerous other places on the dashboard (such as the execution timestamps for proposals).
If the metrics are presented in UTC (which is what I would suspect), then what this shows me is that the transaction rate fell to zero as a result of the subnet having been halted (indicating that transactions were being processed before hand).
I can see that the finalization rate fell to practically zero much earlier in the afternoon though.
It looks like the subnet was processing transactions, but notorisation and/or finalisation was struggling. Looks like the notorisation delay for this subnet is still set to 600ms (many other subnets have had this reduced to 300ms due to performance improvements). I’m curious to find out more when the details can be released.
I’ve adopted the proposal to halt the subnet (which has already executed).