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Teradata RDBMS Database Administration - NCR

NCR Teradata RDBMS Database Administration - NCR , 2004. - 616 p.
Download (direct link): teradatadatabaseadmin2004.pdf
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You cannot create a cluster dump of journal tables.

You cannot set up cluster archives when you are archiving DBC.

You can partially dump non-fallback tables if an AMP is offline.

Fallback tables are always completely dumped, regardless of the configuration.

Single-processor dumps are only used to complete the archive of no-fallback tables after a processor is restored to service.

A cluster archive does not contain any dictionary information.

You must perform a DICTIONARY TABLE archive before you run a cluster archive for the first time, because the DBC database is automatically excluded from this kind of archive operation.

You must run the dictionary table archive again any time there is a change in the structure of the tables in the cluster archive.

Archiving with a Down AMP

When an AMP is off-line during an all-AMP archive, non-fallback tables may only be partially dumped.You need to:

Perform a single-AMP backup

Choose NO FALLBACK TABLES, to obtain a complete backup. (Fallback tables are always completely archived even if a vproc is down, because there is either a primary or fallback copy of the data on another AMP.)

The first DUMP statement performs a backup of ALL of the NO FALLBACK TABLES that reside in DBC User on vproc 0.

This AMP was down during the all-AMP dump. You issue the DUMP statement after the AMP comes back on-line.

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Teradata RDBMS Database Administration Chapter 8: Archiving, Restoring and Recovering Data

Archive Routines (Recommended)

Archive Options

The archive statement includes a number of options, including:

Archive Option Description
RELEASE LOCK Automatically releases Utility Locks if the operation completes successfully.
INDEXES For all-AMP dumps only, this option specifies to include secondary indexes with the archive. You will need more time and media to dump objects with their secondary indexes.
ABORT Causes all AMP or cluster dumps to fail with error messages if an AMP is off-line and the objects to be dumped includes: No fallback tables Single image journals
NONEMPTY DATABASES Instructs the ARC utility to exclude users/databases without tables, views, or macros from the archive.
USE GROUP READ LOCK Permits you to archive as transactions update locked rows. You must define after image journaling for the table during the time the archive is taking place.

Indexes Option

This option applies only to ARCHIVE DATA TABLES ALL AMP.

Archive operations automatically dump primary indexes, but do not automatically dump secondary indexes. The INDEXES option enables you to dump secondary indexes as part of the archive process.

The INDEXES option archives both unique and non-unique secondary indexes on all data tables. However, if an AMP is off-line, the utility only archives unique secondary indexes on fallback tables. It ignores the non-unique indexes. In addition, it does not archive any secondary indexes for non-fallback tables. For this option to be the most effective, it is best to use it when all vprocs are online.

The reverse process is true for restoring data that was archived with the INDEXES option. All indexes are restored if all AMPs are on-line. If an AMP is down, only unique secondary indexes are restored and only for fallback tables. No non-unique secondary indexes are restored. No indexes are restored for non-fallback tables.

Teradata RDBMS Database Administration

8 - 19 Chapter 8: Archiving, Restoring and Recovering Data

Archive Routines (Recommended)

INDEXES option has these ... Explanation
restrictions INDEXES is for use only with all-AMP data table dump operations. The INDEXES option does not apply to dictionary, no fallback, and journal table archive operations. This option is ignored in cluster or single processor dump operations as well as an archive statement that includes the GROUP READ LOCK option.
recommendations The time and media required to perform and archive increases. It will also take you longer to restore an archive you have created with the INDEXES option than to restore an archive created without it. However, it will usually be quicker to restore secondary indexes than rebuild them. In most cases, archive and restore without INDEXES. The following do not dump index subtables: Dictionary, no fallback, or journal table dumps Cluster or single processor dumps Dumps made using a group read lock
results with a DUMP operation If all AMPs are online, then all indexes are dumped. When an AMP is down, for tables with fallback, unique secondary indexes are dumped. For non-fallback tables, no indexes are dumped.
results with a RESTORE operation If all AMPs were online when the archive was written, then all indexes are restored. Otherwise, only unique secondary indexes are restored for tables with fallback protection.

Group Read Lock Option

The group read lock option allows an archive operation to proceed while you and other users make changes to the table.
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