HP NonStop RDF, Руководство по управлению

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FRNL (Step 4, Method 2)
This method can be used for tables with or without SYSKEY or clustering keys.
There are no special considerations for key-sequenced tables with indexes, but see below for
issues regarding the synchronization of indexes.
NonStop SQL/MP and NonStop SQL/MX Tables With Partitions
The utilities associated with and related to the NonStop SQL products have limitations that make
synchronization of individual partitions complicated and difficult. The following represent
methods that enable you to circumvent these limitations.
• SQLCI DUP and MXCI DUP does not have a PARTONLY option. Therefore, you cannot
duplicate only an individual partition.
• While BACKUP and RESTORE have the PARTONLY option, if you have backed up tables
from the primary system, you must use the MAP NAMES option (LOCATION option with
BACKUP and RESTORE 2) when restoring them on the backup system in order to specify
the correct system name. You cannot, however, include both the MAP NAMES (LOCATION
option with BACKUP and RESTORE 2) and PARTONLY options in the RESTORE operation.
Therefore, because you must use MAP NAMES or LOCATION, you cannot restore only a
single partition.
Described below is a set of steps that can be used to synchronize individual partitions of NonStop
SQL/MP tables (either primary or secondary partitions).
NOTE: While the discussion below is concerned with NonStop SQL/MP, the same issues and
resolutions apply for NonStop SQL/MX.
Requirements for Synchronization of Individual Partitions
To synchronize an individual partition of a partitioned table, you must have a copy of the entire
table on the backup system. If you are missing a volume because of a complete media failure
and you do not have a backup copy of the table on tape or in an online dump, then you will have
to resynchronize the entire table. Therefore, to prevent this, you should have a copy of your
backup database on tape or in an online dump. The preferred method is to have on online dump
because it can be used both for fast synchronization after a media failure on the backup system
as well as being able to takeover on the backup system as quickly as possible after your lose your
primary system due to an unplanned outage. If you choose not to take online dumps, then you
should have a copy of all tables on your backup system on tape. The data in the copy on tape
need not be current, but you need to have the physical structure of all tables on tape to facilitate
the ability to resynchronize individual partitions at a later date. To this end, you can employ the
following special trick, but it will not work if you need to resynchronize an individual partition
of a partitioned index. With an online dump, however, you can recover an individual partition
of an index.
Quick Trick for Having a Copy on Tape
1. Rename the table to a temporary name using the SQLCI ALTER TABLE command.
2. Create a duplicate table with the original name of the table you renamed in step 1. This table
must have all the same partitions as the original table.
3. Use BACKUP to put the duplicate table on tape. It will have all the partitions, but they are
empty. Thus, it will not take long to back the partitions up, nor will it take long to restore
any of the partitions.
4. Rename the table to a temporary name and then drop it. By renaming it before dropping it,
you preserve any indexes that are associated with the original table name.
5. Rename the temporary table (step 1) back to the original table name.
Synchronizing Selected Database Portions Online 179