I am using the cluster version 1.2 of Apache IoTDB, and the query task was stuck just now. I tried to execute show query processlist to check for reason, but this task also directly get timed out. I only can restart the IoTDB cluster, and all the query turns to be fine. Since this problem has already disappear, I cannot troubleshoot the reason now, but anyone have any troubleshooting ideas if this problem happens again?
If this error appears again next time, you can use jstack it to see where the query task in Apache IoTDB got stuck. Or you can try updating to the latest version, since this may also be a old version bug.