ALTER SYSTEM

Description

This statement is used to operate nodes in a system. (Administrator only!)

Syntax

1. Add nodes (Please add in this way if multi-tenant functionality is not used).

   ALTER SYSTEM ADD BACKEND "host:heartbeat_port"[,"host:heartbeat_port"...];
   ALTER SYSTEM ADD COMPUTE NODE "host:heartbeat_service_port"[,"host:heartbeat_service_port"...];

   After BE nodes are successfully added to your CelerData cluster, you can execute the SHOW BACKENDS statement to see the newly added nodes. After CN nodes are successfully added to your CelerData cluster, you can execute the SHOW COMPUTE NODES statement to see the newly added nodes.

2. Add idle nodes (Namely, add BACKEND that does not belong to any cluster).

   ALTER SYSTEM ADD FREE BACKEND "host:heartbeat_port"[,"host:heartbeat_port"...];

3. Add nodes to a cluster.

   ALTER SYSTEM ADD BACKEND TO cluster_name "host:heartbeat_port"[,"host:heartbeat_port"...];

4. Delete nodes.

   ALTER SYSTEM DROP BACKEND "host:heartbeat_port"[,"host:heartbeat_port"...];
   ALTER SYSTEM DROP COMPUTE NODES "host:heartbeat_service_port"[,"host:heartbeat_service_port"...];

5. Take nodes offline.

   ALTER SYSTEM DECOMMISSION BACKEND "host:heartbeat_port"[,"host:heartbeat_port"...];

6. Add Broker.

   ALTER SYSTEM ADD BROKER broker_name "host:port"[,"host:port"...];

7. Reduce Broker.

   ALTER SYSTEM DROP BROKER broker_name "host:port"[,"host:port"...];

8. Delete all Brokers.

   ALTER SYSTEM DROP ALL BROKER broker_name

9. Set up a Load error hub for collecting and displaying import errors.

   ALTER SYSTEM SET LOAD ERRORS HUB PROPERTIES ("key" = "value"[, ...]);

Note:

1. host could be a host name and an ip address.

2. heartbeat_port is the heartbeat port of the node.

3. Adding and deleting nodes are synchronous operations. Without considering the existing data on nodes, these two operations delete nodes from the metadata directly. Please operate with caution.

4. Nodes decommission means safely removing the nodes. This operation is asynchronous. If successful, the nodes will be deleted from metadata. If not, they will not be taken offline.

5. Nodes decommission process can be cancelled manually. For more details, please refer to CANCEL DECOMMISSION.

6. Load error hub:

   Currently, only two types of Hub are supported: Mysql and Broker. Please specify "type" = "mysql" or "type" = "broker" in PROPERTIES. To delete the current load error hub, please set the type as null.

   • When using the Mysql type, import errors will be inserted into specified Mysql database table and can be viewed directly through show load warnings statement.

     Hub of Mysql type needs to specify the following parameters:

   host：mysql host
   port：mysql port
   user：mysql user
   password：mysql password
   database：mysql database
   table：mysql table

   • When using the Broker type, import errors will be generated into a file and be written into a designated remote storage system through Broker. Please make sure that corresponding broker is already deployed in the remote system.

     Hub of Broker type needs to specify the following parameters:

   broker: Name of broker
   path: Remote storage path 
   other properties: Other information required for accessing remote storage, e.g. Authentication information, etc. 

Examples

1. Add a node.

   ALTER SYSTEM ADD BACKEND "host:port";

2. Add an idle node.

   ALTER SYSTEM ADD FREE BACKEND "host:port";

3. Delete two nodes.

   ALTER SYSTEM DROP BACKEND "host1:port", "host2:port";

4. Take two nodes offline.

   ALTER SYSTEM DECOMMISSION BACKEND "host1:port", "host2:port";

5. Add two Hdfs Broker.

   ALTER SYSTEM ADD BROKER hdfs "host1:port", "host2:port";

6. Add a load error hub with Mysql type.

   ALTER SYSTEM SET LOAD ERRORS HUB PROPERTIES
   ("type"= "mysql",
   "host" = "192.168.1.17"
   "port" = "3306",
   "user" = "my_name",
   "password" = "my_passwd",
   "database" = "starrocks_load",
   "table" = "load_errors"
   );

7. Add a load error hub with Broker type.

   ALTER SYSTEM SET LOAD ERRORS HUB PROPERTIES
   ("type"= "broker",
   "name" = "bos",
   "path" = "bos://backup-cmy/logs",
   "bos_endpoint" = "http://gz.bcebos.com",
   "bos_accesskey" = "069fc278xxxxxx24ddb522",
   "bos_secret_accesskey"="700adb0c6xxxxxx74d59eaa980a"
   );

8. Delete the current load error hub.

   ALTER SYSTEM SET LOAD ERRORS HUB PROPERTIES
   ("type"= "null");