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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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In this case, for maximum throughput, cluster level operation is recommended with one session per AMP for involved AMPs.

For example, if the system has 50 clusters with 4 AMPs each, you can partition it into two jobs with 25 clusters each and 100 sessions per job provided that your site has two (or more) tape drives available and enough host resources to run two jobs in parallel.

8 - 14 Teradata RDBMS Database Administration

Chapter 8: Archiving, Restoring and Recovering Data

Archive Commands

Archive Commands

The ARC utility offers several commands to perform archive, restore, and recovery tasks. Some commands available for archive-related tasks include:

Command Function
LOGON Begins a session.
LOGOFF Ends a session.
ARCHIVE Archives a copy of a database or table to a host-resident data set/file.
REVALIDATE Housekeeping, cleanup function.
REFERENCES CHECKPOINT Marks a journal for later archive or recovery activities.
RELEASE LOCK Releases host utility locks on databases or tables.

ARCHIVE Command

The ARCHIVE command backs up database objects to host media (usually magnetic tape).

You can specify the archive by:

Type

Object

Level

Option

Archive Types

The archive statement can only back up one type of table at a time: dictionary; data; no fallback; or journal. Users must submit separate statements in order to archive each. Below is a description of each archive type.

Archive Type Description
DATA TABLES Archives fallback and no- fallback tables, views and macros when you archive from ALL AMPs or clusters of AMPs.
NO FALLBACK TABLES Run this archive type only to back up no fallback tables on an AMP that was down during a DATA TABLE archive. It completes the previous ALL AMP or cluster archive.
JOURNAL TABLES Archives the dictionary rows and selected contents of the journal tables.

8 - 14

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

Archive Commands

Archive Type Description
DICTIONARY TABLES Backs up DD rows that describe the databases or tables dumped during a cluster- level archive. If you archive a database, the archive includes table, view, and macro definitions. If you dump a table, back up only includes table definition rows. DD information for permanent journals is not included.

Archive Objects

When you identify that database in an ALL AMP operation, all objects and all DD information for those objects, are archived for the specified database and all its descendents.

An ALL AMPs table dump archives table, column and index information, as well as table headers and data rows.

The EXCLUDE option allows you to exclude a single database, a database and all its descendents, or a range of alphabetically sorted databases.

The objects backed up in an archive operation varies depending upon the type of object you select:

Single database or table

Multiple databases or tables

All databases

Archive Object Type Description
Single or Multiple Table For each table specified in the archive statement, the ARC utility backs up table, column, and index information along with table headers and the actual data rows.
Single Database An ALL AMP database archive backs up a wide range of DD information. It archives all objects that belong to the database including views, macros and the data tables themselves. The information archived for the data tables includes table, column, and index information as well as table headers and data rows. A table header is a row of information about the table that is kept in the first block of the table.
Database ALL A Database ALL archive dumps the parent and all children. The backed up objects are identical to those archived in a single database dump. The EXCLUDE option directly affects which databases are backed up. The exclude option changes the range of objects archived. You can leave out a single database, a database and all of its children, or a range of alphabetically sorted databases.

8 - 14 Teradata RDBMS Database Administration

Chapter 8: Archiving, Restoring and Recovering Data

Archive Commands

Archive Levels

The default archive level for any archive operation is ALL AMPS. Normally, you do not specify an archive level in your DUMP statement, since ALL is the default.

The system performs an ALL AMP-level archive unless you specify a processor or cluster archive. A cluster archive dumps data tables by groups of AMP clusters so that the complete set of archive files contains all data from all AMPs.

Cluster Archives

You can run a cluster archive in parallel, or schedule it to run over several days. It may be faster to restore a single AMP, since the system has fewer tapes to scan to recover lost data.

In general, cluster archiving improves the archive and recovery performance of very large tables. In addition, it simplifies the restore process of non-fallback tables for a specific AMP.

Cluster dumps have the following rules:
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