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system.database_replicas

Contains information of each Replicated database replicas.

Columns:

  • database (String) — The name of the Replicated database is in.

  • is_readonly (UInt8) - Whether the database replica is in read-only mode. This mode is turned on if the config does not have sections with Zookeeper/ClickHouse Keeper.

  • is_session_expired (UInt8) - the session with ClickHouse Keeper has expired. Basically the same as is_readonly.

  • max_log_ptr (UInt32) - Maximum entry number in the log of general activity.

  • zookeeper_path (String) - Path to database data in ClickHouse Keeper.

  • shard_name (String) — The name of the shard in the cluster.

  • replica_name (String) - Replica name in ClickHouse Keeper.

  • replica_path (String) - Path to replica data in ClickHouse Keeper.

  • zookeeper_exception (String) - The last exception message, got if the error happened when fetching the info from ClickHouse Keeper.

  • total_replicas (UInt32) - The total number of known replicas of this database.

  • log_ptr (UInt32) - Maximum entry number in the log of general activity that the replica copied to its execution queue, plus one.

Example

SELECT * FROM system.database_replicas FORMAT Vertical;

Row 1:
──────
database:            db_2
is_readonly:         0
max_log_ptr:         2
replica_name:        replica1
replica_path:        /test/db_2/replicas/shard1|replica1
zookeeper_path:      /test/db_2
shard_name:          shard1
log_ptr:             2
total_replicas:      1
zookeeper_exception: 
is_session_expired:  0