SQL/MX 3.2.1 Reference Manual (H06.26+, J06.15+)

SQL/MX Statements

HP NonStop SQL/MX Release 3.2.1 Reference Manual—691117-005

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Considerations for MODIFY

must ensure that consistency is maintained between the primary and backup

environments when Guardian rename operation is performed.

MODIFY and Redefinition Timestamp

The Guardian rename operation changes the redefinition timestamp of the object but it

is the same physical object with a different Guardian name. Therefore, after Guardian

rename operation is performed, the similarity check will pass. The following example

illustrates this occurrence:

>>prepare q from select * from t1;

--- SQL command prepared.

>>modify table t1

+>rename location <existing location> to <new file name

part>;

--- SQL operation complete.

>>execute q;

*** WARNING[8578] Similarity check passed.

In the example, although execute q uses the original name to access the renamed

table t1, the similarity check passes because table t1 remains the same physical table.

The Guardian rename of a base table changes the redefinition timestamp of the table

but not indexes. However, the Guardian rename of an index changes the redefinition

timestamp of the index, but not the base table and other indexes on that table.

MODIFY and Table Reloading

Some of MODIFY’s options start a FUP RELOAD process that runs in the background.

Until this process completes, you cannot do DDL or utility operations on the file. You

can monitor the reload process’s progress with this command:

FUP STATUS physical-file-name

If FUP STATUS returns a RELOAD COMPLETED message and the physical file is not

being opened by another process, you can start the next MODIFY operation. Note that

the ORSERV process started by the reload operation might still open the physical file a

bit longer (about five minutes) even though FUP STATUS already returns the RELOAD

COMPLETED message.

Note. You must stop the RDF updaters to perform Guardian rename on the backup system.

After the rename operation is complete, restart the RDF updaters.