Influxdb freeze after a few hours running

Influxdb freeze after a few hours running.It still can product influxd.log file but can’t execute a sql or a write order. And it also can’t write any monitor information to _internal database. Someone has some clues on it? BTY, my influxdb version is 1.5.2

Did slow query can lead to this situation? I found some slow queries executed every 10 minutes by chronograf SHOW QUERIES.

We would need more info to diagnose this. How does CPU/Memory/Swap look? Is the syslog or influx logs producing anything? Is SHOW QUERIES the only entry in the slow queries log?

Also is there a reason you are running 1.5.2? 1.7.0 came out recently and InfluxData releases a ton of performance tweaks and bug fixes with every release