SQL/MP Reference Manual

HP NonStop SQL/MP Reference Manual—523352-013
M-25
Considerations—MODIFY LABEL with REPLACE
NODENUMBER
begin with SQL, specifying $VOL1.SQL*.* is more efficient than specifying
$VOL1.*.*. The MODIFY LABEL with REPLACE NODENUMBER command would
not have to search for SQL objects on other subvolumes.

Multiple MODIFY commands (including LABEL, CATALOG, and REGISTER
commands) can be run concurrently on the same node as long as each command
is processing a different set of files or catalogs. For example, if the node number is
changed on a node that has an SQL database spread out over five volumes, five
MODIFY LABEL with REPLACE NODENUMBER commands can be started
concurrently, each specifying a different volume to be modified. Note that in such a
case, because the node name did not change, it would not be necessary to run
any MODIFY CATALOG commands.

MODIFY LABEL with REPLACE NODENUMBER locks one file label at a time. The
file itself is not locked. There is nothing to prevent the user from accessing a
partially modified data dictionary. The user should refrain from using the database,
including partitions and dependent objects on remote nodes, until the node
numbers have been modified.

The MODIFY DICTIONARY utility does not handle:

Remote nodes. If you specify a remote file name, the MODIFY LABEL with
REPLACE NODENUMBER command reports a nonfatal error. Each node with
dependent objects or partitioned objects must have a version of NonStop
SQL/MP that supports MODIFY LABEL with REPLACE NODENUMBER
commands.

User-defined SQL object files. For example, MODIFY LABEL with REPLACE
NODENUMBER does not modify a node number stored in a column of a user-
defined table.

Node numbers stored in SQL object program files.

Node numbers in Enscribe file labels. In Enscribe file labels, local file names
are stored as local names and thus do not contain a node number. However, a
reference to an alternate key file or a partition file does include a node number
if the alternate key file or partition file is stored on a different node.
If a disk containing an alternate key file or a partition file is moved to a different
node, the FUP ALTER command can be used to change the Enscribe file label
that references the file that moved. Note that changes must be made to the
Enscribe file labels that point to the disk that moved, not to the alternate key
file label or partition file label that resides on the disk that moved.

Dependent objects. Node numbers in the file labels of dependent objects are
not modified unless the dependent object is specified in the MODIFY LABEL
with REPLACE NODENUMBER command.
For example, suppose that a table T1 resides on the \SYS1.$DB1.OBJECTS
subvolume and is registered in the \SYS1.$DB1.CAT catalog, and its
dependent index I1 resides on the \SYS2.$DBS.OBJECTS subvolume and is
registered in the \SYS2.$DBS.CAT catalog. Suppose that the $DBS disk is