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SHOW DATABASE STATUS
Shows MemSQL database status.
Syntax
[USING db_name] SHOW DATABASE STATUS
Remarks
In case of cluster replication, the viewpoints of the primary and secondary clusters may differ. In this case, the primary cluster is unaware of the secondary cluster, whereas the secondary cluster is aware of the primary cluster. Hence, the command may return different results when run.
The following table provides information on the metrics displayed in the output:
| Key | Description |
|---|---|
| database | Name of the database in the MemSQL instance |
| role | Database replication role |
| state | Current state of the database (See Database States for more information) |
| commit_count | Number of committed transactions. (This field is deprecated) |
| provision_file | Position (of the snapshot) from which the database has been provisioned |
| oldest_living_snapshot | Position of the oldest available snapshot (for the database) on the disk |
| newest_snapshot | Position of the most recent snapshot (for the database) on the disk |
| log_type | Durability type of the log, sequential or paged |
| commit_lsn | Position before which all pages are committed |
| hardened_lsn | Position before which all pages have been written |
| replay_lsn | Position before which all pages have been replayed. Applies only to secondary databases |
| tail_lsn | Highest position of all the pages |
| replicated_committed_lsn (primary) | Position before which all commits are replicated to the secondary databases |
| term | The term of the database, used to uniquely identify which node was the master of a specific database |
| replay_fileid | Used in combination with replay_offset to find the current replay position (This field is deprecated) |
| sync_offset | This field is deprecated |
| state_machine_stage | Provides the current stage of the replication state machine |
| state_machine_error | Provides the error associated with the replication state machine |
| state_machine_throttling | Provides the current state of the replication state machine |
| replay_stuck_on_low_memory | Specifies if the replay is stalling because of low memory |
| replay_offset (secondary) | Used in combination with replay_fileid to find the current replay position. (This field is deprecated) |
| network_fileid (secondary) | Used in combination with network_offset to find the position in log file that has been replicated. (This field is deprecated) |
| network_offset (secondary) | Used in combination with network_fileid to find the position before which the log file has been replicated. (This field is deprecated) |
| is_connected_to_master (secondary) | Specifies if the secondary partition is connected to the primary partition |
| replication_type (secondary) | Specifies the replication type (async or sync). This metric is local to the secondary database, and can be different from the distributed database’s replication state |
| master_host (secondary) | The host component (of the primary database) in the host:port/database_name URI format |
| master_port (secondary) | The port component (of the primary database) in the host:port/database_name URI format |
| master_user (secondary) | Name of the user |
| master_database (secondary) | The name of the primary database |
| auto_reprovision (secondary) | This field is deprecated |
| partitions | The number of partitions. This value is non-zero for reference databases and zero for partitions and other databases |
Note: LSN stands for Log Sequence Number, and represents the position in the log file.
Examples
The following example shows the output when the command is run on the primary cluster.
USE memsql_demo;
SHOW DATABASE STATUS;
****
+--------------------------+--------+
| Key | Value |
+--------------------------+--------+
| database | x_db |
| role | master |
| state | online |
| commit_count | 0 |
| provision_file | 0 |
| oldest_living_snapshot | 0 |
| newest_snapshot | 0 |
| log_type | paged |
| commit_lsn | 0:2 |
| hardened_lsn | 0:2 |
| replay_lsn | 0:0 |
| tail_lsn | 0:2 |
| replicated_committed_lsn | 0:1 |
| term | 2 |
| workload_throttled | no |
| partitions | 6 |
+--------------------------+--------+
The following example displays the output from the secondary cluster’s viewpoint.
USE memsql_demo;
SHOW DATABASE STATUS;
****
+----------------------------+-------------+
| Key | Value |
+----------------------------+-------------+
| database | x_db |
| role | slave |
| state | replicating |
| commit_count | 0 |
| provision_file | 0 |
| oldest_living_snapshot | 0 |
| newest_snapshot | 0 |
| log_type | paged |
| commit_lsn | 0:1 |
| hardened_lsn | 0:2 |
| replay_lsn | 0:1 |
| tail_lsn | 0:2 |
| replicated_committed_lsn | 0:0 |
| term | 2 |
| is_connected_to_master | yes |
| replication_type | async |
| master_host | 127.0.0.1 |
| master_port | 10000 |
| master_user | distributed |
| master_database | x_db |
| state_machine_stage | packet wait |
| state_machine_state | x_streaming |
| state_machine_error | no |
| state_machine_throttling | no |
| replay_stuck_on_low_memory | no |
| partitions | 6 |
+----------------------------+-------------+
