Early watchdog warning: a tick has run for over 10 seconds (Creating thread dump)
- Platforms
- Paper · Purpur · single server
- Verified
- Verified
- Confidence
- Confidence 90%
What it looks like in the log
Any one of these lines is enough. The agent matches them locally, on your server.
logs/latest.log
[ERROR] has not responded for
Symptoms
- The server “freezes” for several seconds for all players
- In the log: “The server has not responded for N seconds! Creating thread dump” and a Server thread dump
Cause
The current tick has run longer than early-warning-delay (10 s by default). Paper prints a dump of the main thread — the server is still running, but if the tick does not finish before timeout-time, the watchdog will stop it.
Possible causes
- A plugin is performing a blocking operation on the main thread (SQL/HTTP, file I/O)
- A long world/chunk save or a large WorldEdit operation
- CPU starvation or a long GC pause
How to fixLow risk
- In the
Server threaddump under the evidence, find the first plugin frames — that is the likely source of the hang. - If it keeps recurring with the same plugin, update it or schedule its heavy functions (saving, queries) for times with no players online; report it to the author with the dump.
- If the dump shows world saving, check disk speed and free space.
- For monitoring, use
/spark profiler --only-ticks-over 100to catch long ticks.
Translated from the Russian original; log lines are quoted verbatim.