OrientDB Manual

SQL - ALTER CLUSTER

The Alter Cluster command updates a cluster.

Syntax

ALTER CLUSTER <cluster-name>|<cluster-id> <attribute-name> <attribute-value>

Where:

  • cluster-name name of the cluster to modify
  • cluster-id id of the cluster to modify
  • attribute-name between those supported:
    • NAME cluster's name
    • STATUS change the cluster's status. Allowed values: ONLINE, OFFLINE. By default clusters are ONLINE. To put cluster offline, change it status to OFFLINE. Once offline, the physical files of the cluster will be not open by OrientDB. This feature is useful when you want to archive old data elsewhere and restore when needed
    • COMPRESSION compression used between: nothing, snappy, gzip and any other compression registered in OCompressionFactory class. OrientDB calls the compress() method every time it saves a record to the storage, and uncompress() every time it loads a record from the storage. You can also use the OCompression interface to manage encryption
    • USE_WAL use the Journal (Write Ahead Log) when OrientDB operates against the cluster
    • RECORD_GROW_FACTOR grow factor to save more space on record creation. This is useful when you plan to update the record with additional information. Bigger record avoids defragmentation because OrientDB has not to find a new space in case of update with more data
    • RECORD_OVERFLOW_GROW_FACTOR like RECORD_GROW_FACTOR, but on update. When the size limit is reached this setting is considered to get more space (factor > 1)
    • CONFLICTSTRATEGY, (since 2.0) is the name of the strategy used to handle conflicts when OrientDB's MVCC finds an update or delete operation executed against an old record. If not defined a strategy at cluster level, the database configuration is taken (use ALTER DATABASE command for this). While it's possible to inject custom logic by writing a Java class, the out of the box modes are:
    • version, the default, throws an exception when versions are different
    • content, in case the version is different, it checks if the content is changed, otherwise use the highest version and avoid throwing exception
    • automerge, merges the changes
  • attribute-value attribute's value to set

See also

Examples

ALTER CLUSTER profile NAME profile2

ALTER CLUSTER 9 NAME profile2

ALTER CLUSTER V CONFLICTSTRATEGY automerge

Put a cluster offline

ALTER CLUSTER V_2012 STATUS OFFLINE

To know more about other SQL commands, take a look at SQL commands.