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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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Enter a name for the output Archive file.

Enter any optional parameters (which may include the archive options).

Optional Archive Parameters

Entries for all parameters are applied to the ARCHIVE statement when you select 'OK.' The optional parameters you can specify on the Archive can be entered on the Archive Screen.

These parameters allow you to specify:

Databases or tables to exclude from the archive.

A list of AMPs to be archived. If none are entered, all AMPs or all within the specific Cluster or Clusters are archived.

A list of Clusters to include in the archive. When you don't specify a value here, all Clusters are archived unless you specified particular AMPs.

Whether or not the locks should be released when the archive is complete.

That a Group Read lock should be applied. Remember, Group Read Locks require After Image Journaling on all objects archived.

That the archive should abort if an AMP fails.

Whether or not indexes should be archived.

Exclusion of empty databases.

That you want the row count output.

A secondary file name for mirroring the output.

Using the No Restart (NR) option, your archive job will not be checkpointed, so ARCMAIN cannot automatically restart the job from the point of failure. You will have to start your job from the beginning if you encounter an error during the archive. However, your archive job will run much faster.

To use the NR option, simply rename your arc script with the NR. prefix. For example, if your script name was dumpdbc, to use the NR option rename it to NR.dumpdbc.

Chapter 8: Archiving,

Scripts

Archiving a

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

Scripts

Syntax Checker

You can request that the script you have created be checked for syntax errors by selecting the Syntax Checker option on the bottom of the Create Script screen. The syntax will then be checked without running the script.

After you have checked the syntax, you may want to save the script by selecting Save on this screen also.

You may not have any syntax errors if your script was created as a result of using the functions on the screen. However, if you type in the script or edit an existing script by changing the entries, you may have syntax errors.

Teradata RDBMS Database Administration

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Archive Commands

Session Control

To use the ARC utility, you must log on with a LOGON statement to start a session before you can execute other ARC statements. The user ID with which you log on has to have privileges for the ARC statements that you want to use.

LOGON/LOGOFF statements

LOGON statement processing:

Two sessions logged on, one for SQL statements and one for control requests.

At DUMP or RESTORE command, ARC starts additional sessions.

Identifies account to charge for resources.

Identifies user to Teradata and verifies ownership and privileges.

CHECKPOINT permits you to execute both the SQL and ARC utility checkpoint statements.

DUMP permits you to execute the Archive statement.

RESTORE permits you to execute the following ARC statements: Restore, Delete Journal, Rollforward, Release Lock, Rollback, Build.

LOGOFF statement example:

Ends all Teradata sessions logged on by the task.

Terminates the utility.

To release a lock held by another user, you must specify Override and hold DROP privileges on the underlying objects.

Multiple Sessions

You can specify the number of archive and/or recover sessions with which to work, or use the default. To set the number, use the SESSIONS runtime parameter.

The optimum number of sessions is:

One per AMP for archive.

Two per AMP for recovery.

The number of sessions to use can vary based on a number of factors. Several are described below. Two or three sessions per AMP is a good starting point.

The vprocs use the sessions as follows:

Teradata assigns each session to a vproc. All sessions stay with that vproc until all required data is archived. Then it will be moved to another vproc if necessary.

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

Archive Commands

Archive attempts to build blocks from each vproc in turn. The blocks are composed of complete database blocks.

Data blocks from different vprocs are never mixed within the same archive block.

If fewer than one session per vproc is specified for the archive:

For vproc groups, archive/ recovery will archive blocks from each group with each vproc completed before the next starts.

In this case, a large number of sessions allocated to recovery will not help recovery performance.

For larger configurations, say over 100 AMPs, specifying one session per AMP will not increase performance because of other limiting component(s).
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