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  6. ALTER NODE GROUP

ALTER NODE GROUP

Function

ALTER NODE GROUP modifies the information about a Node Group.

Precautions

Only a system administrator is allowed to modify Node Group information. Node Group modification operations (excluding SET DEFAULT) are internal and needs to be performed in maintenance mode (by invoking set xc_maintenance_mode=on;). ALTER NODE GROUP can be used only within a database. To avoid data inconsistency in DBMS, do not manually run this SQL statement.

Syntax

ALTER NODE GROUP groupname
    | SET DEFAULT
    | RENAME TO new_group_name
    | SET VCGROUP RENAME TO new_group_name
    | SET NOT VCGROUP
    | SET TABLE GROUP new_group_name

Parameter Description

  • groupname

    Specifies the Node Group to be renamed.

    Value range: a string compliant with the naming convention rules

  • SET DEFAULT

    Sets in_redistribution to 'y' for all Node Groups excluding the one specified by groupname. To be compatible with earlier versions, this syntax is retained and does not need to be executed in maintenance mode.

  • RENAME TO new_group_name

    Rename the Node Group specified by groupname to new_group_name.

  • SET VCGROUP RENAME TO new_group_name

    Converts the entire physical cluster into a logical cluster. After the conversion, groupname is the logical cluster name, and the original physical cluster is changed to new_group_name.

  • SET NOT VCGROUP

    Converts all logical clusters to common Node Groups and changes group_kind from 'v' to 'n' for all of them.

  • SET TABLE GROUP new_group_name

    Changes all the group_names in the pgroup columns of the pgxc_class tables on all CNs to new_group_name.