Company or project name
No response
Use case
After a keeper cluster rolling restart, currently it is very likely that server-to-keeper connections can get imbalanced. Although we have a solution using fallback session but they take longer time to balance the keeper connections given their defaults are high (3 & 6 hours). We can't reduce them to low values since it may have unexpected impact. Hence if the operator of cluster is aware of this imbalance and want to take action, one way to forcefully disconnect and reconnect to keeper on each of the server nodes. This should help in rebalancing the keeper connections.
Describe the solution you'd like
We would like to have a SYSTEM command for triggering the disconnect and reconnecting to keeper.
Looking at the current nomenclature of system commands (SYSTEM <action> <object>) we can name it as SYSTEM RECONNECT ZOOKEEPER or SYSTEM RECONNECT KEEPER.
I would prefer to use ZOOKEEPER since we still use zookeeper in our clickhouse codebase and docs.
Not sure if the action should be named as RECONNECT or DISCONNECT I think the SYSTEM command will only disconnect and clickhouse server will automatically reconnect once it notices that, so probably DISCONNECT is better option. At the same time, DISCONNECT may sound dangerous operation to clickhouse users so probably RECONNECT is better option :)
Describe alternatives you've considered
No response
Additional context
No response
Company or project name
No response
Use case
After a keeper cluster rolling restart, currently it is very likely that server-to-keeper connections can get imbalanced. Although we have a solution using fallback session but they take longer time to balance the keeper connections given their defaults are high (3 & 6 hours). We can't reduce them to low values since it may have unexpected impact. Hence if the operator of cluster is aware of this imbalance and want to take action, one way to forcefully disconnect and reconnect to keeper on each of the server nodes. This should help in rebalancing the keeper connections.
Describe the solution you'd like
We would like to have a
SYSTEMcommand for triggering the disconnect and reconnecting to keeper.Looking at the current nomenclature of system commands (
SYSTEM <action> <object>) we can name it asSYSTEM RECONNECT ZOOKEEPERorSYSTEM RECONNECT KEEPER.I would prefer to use
ZOOKEEPERsince we still use zookeeper in our clickhouse codebase and docs.Not sure if the action should be named as
RECONNECTorDISCONNECTI think theSYSTEMcommand will only disconnect and clickhouse server will automatically reconnect once it notices that, so probablyDISCONNECTis better option. At the same time,DISCONNECTmay sound dangerous operation to clickhouse users so probablyRECONNECTis better option :)Describe alternatives you've considered
No response
Additional context
No response