Alter Cluster command is to update attributes on an existing cluster. In this chapter you can learn how to add or modify the attributes of a cluster.
The following statement is the basic syntax of Alter Cluster command.
ALTER CLUSTER <cluster> <attribute-name> <attribute-value>
Following are the details about the options in the above syntax.
<cluster> − Defines the cluster name.
<attribute-name> − Defines the attribute you want to change.
<attribute-value> − Defines the value you want to set for this attribute.
The following tabular format provides the list of supported attributes you can use along with Alter cluster command.
| Name | Type | Description |
|---|---|---|
| NAME | String | Changes the cluster name. |
| STATUS | String | Changes the cluster status. Allowed values are ONLINE and OFFLINE. By default, clusters are online. |
| COMPRESSION | String | Defines the compression type to use. Allowed values are NOTHING, SNAPPY, GZIP, and any other compression types registered in the OCompressionFactory class. |
| USE_WAL | Boolean | Defines whether it uses the Journal when OrientDB operates against the cluster |
| RECORD_GROW_FACTO R | Integer | Defines the grow factor to save more space on record creation. You may find this useful when you update the record with additional information. |
| RECORD_OVERFLOW_GR OW_FACTOR | Integer | Defines grow factor on updates. When it reaches the size limit, is uses this setting to get more space, (factor > 1). |
| CONFLICTSTRATEGY | String | Defines the strategy it uses to handle conflicts in the event that OrientDB MVCC finds an update or a delete operation it executes against an old record. |
The following table provides the list of Conflict strategies.
| Sr.No. | Strategy & Description |
|---|---|
| 1 | VersionThrows an exception when versions are different. This is the default setting. |
| 2 | ContentIn the event that the versions are different, it checks for changes in the content, otherwise it uses the highest version to avoid throwing an exception. |
| 3 | AutomergeMerges the changes. |
Example
Try the following example queries to learn Alter cluster command.
Execute the following command to change the name of a cluster from Employee to Employee2.
orientdb {db = demo}> ALTER CLUSTER Employee NAME Employee2
If the above command is executed successfully, you will get the following output.
Cluster updated successfully
Execute the following command to change the name of a cluster from Employee2 to Employee using cluster ID.
orientdb {db = demo}> ALTER CLUSTER 12 NAME Employee
If the above command is executed successfully, you will get the following output.
Cluster updated successfully
Execute the following command to change the cluster conflict strategy to automerge.
orientdb {db = demo}> ALTER CLUSTER V CONFICTSTRATEGY automerge
If the above command is executed successfully, you will get the following output.
Cluster updated successfully