Disable the default trace and system_health on new instances#1005
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SimonCropp merged 1 commit intoJul 20, 2026
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Both write diagnostics for the life of the instance into the directory LocalDB owns, which is never cleaned while the instance exists. Measured across ~280 instances they account for 18% of the on-disk size, and neither is of much use for a throwaway test instance. This is not a speed up. Both are written in the background rather than on the startup path: over five stop/start cycles a tuned instance averaged 891ms against 896ms for a baseline one, which is noise. The commands go in GetOptimizeModelDbCommand, which only runs when the instance is created, and the settings live in master so they hold for the life of the instance. hkenginexesession, the other event session writing to that directory, is owned by the XTP engine, is absent from sys.server_event_sessions and cannot be altered.
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Both write diagnostics for the life of the instance into the directory LocalDB owns, which is never cleaned while the instance exists. Measured across ~280 instances they account for 18% of the on-disk size, and neither is of much use for a throwaway test instance.
This is not a speed up. Both are written in the background rather than on the startup path: over five stop/start cycles a tuned instance averaged 891ms against 896ms for a baseline one, which is noise.
The commands go in GetOptimizeModelDbCommand, which only runs when the instance is created, and the settings live in master so they hold for the life of the instance.
hkenginexesession, the other event session writing to that directory, is owned by the XTP engine, is absent from sys.server_event_sessions and cannot be altered.