Replica leadership in Clickhouse
I would like to have more details on the leadership of a replica (ie. system.replicas.is_leader) in a ClickHouse DB.
The documentation states the following :
is_leader: Whether the replica is the leader.
Only one replica can be the leader at a time. The leader is responsible for selecting background merges to perform.
Note that writes can be performed to any replica that is available and has a session in ZK, regardless of whether it is a leader.
This appears vague to me.
Does someone have more details about a leader replica?
Is there something to care about with a leader replica?
Can I read/write to/from a leader replica, like a standard one?
How does the leader election work?
When do the leadership change?
clickhouse
edited Nov 25 '18 at 16:31
user6910411
34.8k1084106
asked Nov 23 '18 at 14:28
ntochiurntochiur
12
add a comment |
I would like to have more details on the leadership of a replica (ie. system.replicas.is_leader) in a ClickHouse DB.
The documentation states the following :
is_leader: Whether the replica is the leader.
Only one replica can be the leader at a time. The leader is responsible for selecting background merges to perform.
Note that writes can be performed to any replica that is available and has a session in ZK, regardless of whether it is a leader.
This appears vague to me.
Does someone have more details about a leader replica?
Is there something to care about with a leader replica?
Can I read/write to/from a leader replica, like a standard one?
How does the leader election work?
When do the leadership change?
clickhouse
edited Nov 25 '18 at 16:31
user6910411
34.8k1084106
asked Nov 23 '18 at 14:28
ntochiurntochiur
12
add a comment |
I would like to have more details on the leadership of a replica (ie. system.replicas.is_leader) in a ClickHouse DB.
The documentation states the following :
is_leader: Whether the replica is the leader.
Only one replica can be the leader at a time. The leader is responsible for selecting background merges to perform.
Note that writes can be performed to any replica that is available and has a session in ZK, regardless of whether it is a leader.
This appears vague to me.
Does someone have more details about a leader replica?
Is there something to care about with a leader replica?
Can I read/write to/from a leader replica, like a standard one?
How does the leader election work?
When do the leadership change?
clickhouse
edited Nov 25 '18 at 16:31
user6910411
34.8k1084106
asked Nov 23 '18 at 14:28
ntochiurntochiur
12
I would like to have more details on the leadership of a replica (ie. system.replicas.is_leader) in a ClickHouse DB.
The documentation states the following :
is_leader: Whether the replica is the leader.
Only one replica can be the leader at a time. The leader is responsible for selecting background merges to perform.
Note that writes can be performed to any replica that is available and has a session in ZK, regardless of whether it is a leader.
This appears vague to me.
Does someone have more details about a leader replica?
Is there something to care about with a leader replica?
Can I read/write to/from a leader replica, like a standard one?
How does the leader election work?
When do the leadership change?
clickhouse
clickhouse
edited Nov 25 '18 at 16:31
user6910411
34.8k1084106
asked Nov 23 '18 at 14:28
ntochiurntochiur
12
edited Nov 25 '18 at 16:31
user6910411
34.8k1084106
asked Nov 23 '18 at 14:28
ntochiurntochiur
12
edited Nov 25 '18 at 16:31
user6910411
34.8k1084106
edited Nov 25 '18 at 16:31
user6910411
34.8k1084106
edited Nov 25 '18 at 16:31
user6910411
34.8k1084106
34.8k1084106
asked Nov 23 '18 at 14:28
ntochiurntochiur
12
asked Nov 23 '18 at 14:28
ntochiurntochiur
12
asked Nov 23 '18 at 14:28
ntochiurntochiur
12
12
add a comment |
add a comment |
1 Answer
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oldest
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Leader replica just coordinates some background processes, leveraging ZooKeeper cluster. So unlike master/slave setup in other DBMS, in ClickHouse you shouldn't care about replica leadership status for reads and writes.
More details are over here: https://clickhouse.yandex/docs/en/operations/table_engines/replication/
answered Dec 8 '18 at 17:01
Ivan BlinkovIvan Blinkov
1,6731016
add a comment |
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1 Answer
1
active
oldest
votes
1 Answer
1
active
oldest
votes
active
oldest
votes
active
oldest
votes
Leader replica just coordinates some background processes, leveraging ZooKeeper cluster. So unlike master/slave setup in other DBMS, in ClickHouse you shouldn't care about replica leadership status for reads and writes.
More details are over here: https://clickhouse.yandex/docs/en/operations/table_engines/replication/
answered Dec 8 '18 at 17:01
Ivan BlinkovIvan Blinkov
1,6731016
add a comment |
Leader replica just coordinates some background processes, leveraging ZooKeeper cluster. So unlike master/slave setup in other DBMS, in ClickHouse you shouldn't care about replica leadership status for reads and writes.
More details are over here: https://clickhouse.yandex/docs/en/operations/table_engines/replication/
answered Dec 8 '18 at 17:01
Ivan BlinkovIvan Blinkov
1,6731016
add a comment |
Leader replica just coordinates some background processes, leveraging ZooKeeper cluster. So unlike master/slave setup in other DBMS, in ClickHouse you shouldn't care about replica leadership status for reads and writes.
More details are over here: https://clickhouse.yandex/docs/en/operations/table_engines/replication/
answered Dec 8 '18 at 17:01
Ivan BlinkovIvan Blinkov
1,6731016
Leader replica just coordinates some background processes, leveraging ZooKeeper cluster. So unlike master/slave setup in other DBMS, in ClickHouse you shouldn't care about replica leadership status for reads and writes.
More details are over here: https://clickhouse.yandex/docs/en/operations/table_engines/replication/
answered Dec 8 '18 at 17:01
Ivan BlinkovIvan Blinkov
1,6731016
answered Dec 8 '18 at 17:01
Ivan BlinkovIvan Blinkov
1,6731016
answered Dec 8 '18 at 17:01
Ivan BlinkovIvan Blinkov
1,6731016
answered Dec 8 '18 at 17:01
Ivan BlinkovIvan Blinkov
1,6731016
1,6731016
add a comment |
add a comment |
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