ALTER LOGICAL SERVER Statement

Modifies configuration for the existing user-defined logical server in the database.

Syntax

ALTER LOGICAL SERVER  logical-server-name   
	{ alter_clause }

Parameters

  • alter_clause: – 
    {ADD MEMBERSHIP  '(' { ls-member, ... } ')' 
| DROP MEMBERSHIP '(' { ls-member, ... } ')'
}
  • ls-member: – 
    FOR LOGICAL COORDINATOR 
| mpx-server-name

Examples

  • Example 1 – This example alters a user-defined logical server by adding multiplex nodes n1 and n2 to logical server ls1:
    ALTER LOGICAL SERVER ls1 ADD MEMBERSHIP (n1, n2)
  • Example 2 – This example adds logical membership of COORDINATOR and drops a named membership of the current coordinator node n1 from logical server ls1:
    ALTER LOGICAL SERVER ls1 ADD MEMBERSHIP (FOR LOGICAL COORDINATOR)
ALTER LOGICAL SERVER ls1 DROP MEMBERSHIP (n1)

Usage

Applies to multiplex only.

logical-server-name refers to an existing user-defined logical server name, in other words, it cannot be a built-in or reserved logical server name. The SYS.ISYSIQLSMEMBER system table stores definitions for the logical server memberships.

A member node that is added to or dropped from a logical server starts or stops accepting logical server connections only after the TLV log corresponding to ALTER LOGICAL SERVER is played on that node. Existing connections of a logical server continue to run on a node when that node is dropped from the logical server, however, distributed processing is stopped for these connections.

An error is returned if:
  • Any ls-member specified with the ADD MEMBERSHIP clause is already a member of the logical server.
  • Any ls-member specified with the DROP MEMBERSHIP clause is not an existing member of the logical server.
  • Logical server membership change causes membership overlap check to fail.

Permissions

Must have DBA or MPX ADMIN authority.

Parent topic: SQL Statements