SQL/MX 2.x Installation and Management Guide (G06.24+, H06.03+)

Performing Recovery Operations
HP NonStop SQL/MX Installation and Management Guide—523723-004
12-3
Recovering Files With the TIME Option
online dump following a create operation. If you do not do so, you cannot recover
the file because TMF looks for a starting point on the latest online dump.
•
A REDONEEDED or UNDONEEDED flag in the FILEINFO display for a file, after a
volume has been enabled for TMF processing, indicates that you must use file
recovery to recover the file.
•
To recover SQL/MX tables, use TMF file sets consisting of the Guardian names of
the underlying files making up the tables and related indexes, in the RECOVER
FILES command. To convert the ANSI names of the tables to their underlying
Guardian file names, run the MXGNAMES utility as described in Appendix B,
Using Guardian Names With TMF, RDF, and Measure and the SQL/MX Reference
Manual.
Recovering Files With the TIME Option
By using the file recovery feature with the TIME option, you can resolve several types
of problems:
•
If a database object is dropped by accident, you can use the TIME option to
recover the object's file as it existed just prior to the drop. This action effectively
recovers the entire file but not the catalog definition of the object.
•
If an application error updates the database in an inconsistent way, you can
recover the database to the state it was in at a specified time before the error
occurred.
•
If a licensed MXCI or mxtool GOAWAY operation incorrectly alters or damages
the database or catalogs, you can recover the database or catalogs to their
previous state.
•
If you have a saved test database or starting database, you can recover that
database to the same point many times. Suppose that in your testing procedures
you need to always start with the same database. This database can be loaded to
the node or recovered by using TMF file recovery with the TIME option.
Using file recovery with the TIME option can be difficult, however, because this method
requires you to coordinate the recovery of interrelated objects, such as tables and their
indexes.
For more information about using file recovery with the TIME option, see the TMF
Operations and Recovery Guide.
Caution. TMF carries no information about the relationships between file labels and catalogs.
If a table is dropped, for example, file recovery cannot restore the catalog entries for the table.
If the file recovery operation starts at a time just before a table was dropped, you might lose
subsequent DDL changes.