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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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Dumps From Unexpected Errors (UNIX) at any time. If an unexpected error occurs while the system is trying to save a PDE crashdump, the system copies the PDE crashdump into the /pdedump file system. The Coroner utility used by TSC cannot access PDE dumps that are copied in this manner; however, TSC may be able to assist you.

Forcing a PDE Crashdump

You can restart the Teradata RDBMS without causing a reboot using one of the following methods (also see "Forced Restarts" on page 9-5):

In the DB Window, open the Supervisor window icon and enter the following command:

restart tpa dump=yes comment

where comment is text explaining of the restart.

The system performs a PDE crashdump and a cold or coldwait restart. (For details, see "Restarts of the Teradata RDBMS" on page 9-3 and "RESTART" under "Vproc Manager Utility" in Teradata RDBMS Utilities.)

On Windows 2000, you can access the Teradata Command Prompt window and enter the tpareset command:

Start -> Programs -> Teradata RDBMS -> Teradata Command Prompt tpareset -d comment

The tpareset command has basically the same effect as the restart command in the DBW.

The -d option forces a PDE Crashdump.

The system performs a cold restart and a PDE Crashdump.

Whichever command you choose to execute, the system prompts you for a confirmation.

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Teradata RDBMS Database Administration Chapter 10: Handling Teradata Crashdumps

Administering PDE Crashdumps

Crashloop Control

Crashloops on UNIX

If the Teradata RDBMS restarts repeatedly due to some error, it is likely that another PDE crashdump will be captured before the last one was completely saved.

When the Teradata RDBMS comes back up, it will start saving the new PDE crashdump and will not get to the original one until the new one is saved. However, once the original problem is corrected, all PDE crashdumps in the dump area will be saved eventually.

The First In, First Out (FIFO) operation in the dump area assures that the most recent data is captured in the dump area.

No Crashloops on Windows 2000

PDE crashdumps are saved in separate directories, so no such coordination is required.

Teradata RDBMS Database Administration

10 - 19 Chapter 10: Handling Teradata Crashdumps

Unloading PDE Crashdumps on Windows 2000

Handling PDE Crashdumps on UNIX MP-RAS

Use the xctl utility to verify that PDE crashdumps are set up to be saved automatically. The Debug fields should read as follows:

xctl Field Name Value Purpose
Dump Type UNIX Save the UNIX System dump if UNIX panics.
System
Save Dump On Enable the automatic transfer of PDE dumps
from the dump device to Crashdumps.

Save Considerations

A PDE Crashdump cannot be saved if:

On UNIX, you turned off the Save Dump option via the xctl utility (the default is off on Windows 2000 because dumps are saved as flat files; see "Handling PDE Crashdumps on Windows 2000" on page 10-22)

DBC.Crashdumps is full

An AMP is down and FALLBACK is not defined for DBC.Crashdumps

Teradata RDBMS is not up

The last PDE crashdump taken is the first one saved. As soon as the system successfully saves a PDE crashdump, the system releases the space the PDE crashdump occupied in the dump area for reuse by the next PDE crashdump the system captures.

Time Considerations

The time required for a PDE crashdump to be saved depends on the size of the PDE crashdump and how much other database activity is occurring. It is not uncommon for a PDE crashdump save to take an hour or more per PDE crashdump.

Dumps After Restarts

After a restart, automatic saves of PDE crashdumps into the DBC.Crashdumps database normally begin as soon as Teradata RDBMS startup is complete. If Teradata RDBMS restarts repeatedly due to some error, it is likely that another PDE crashdump will be captured before the last one was completely saved.

When the Teradata RDBMS comes back up, it will start saving the new PDE crashdump, and will not get to the original one until the new one is saved.

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Teradata RDBMS Database Administration Chapter 10: Handling Teradata Crashdumps

Unloading PDE Crashdumps on Windows 2000

However, once the original problem is corrected, all PDE crashdumps will eventually be saved.

Error Logging

Error messages related to saving PDE crashdumps are logged in the log /var/adm/usererr and in the consolidated AWS console.

PDE Crashdumps

To save crashdumps manually, disable the system from saving PDE crashdumps (for example, if you determine that the act of trying to save a PDE crashdump is causing Teradata RDBMS errors) by turning off the Save Dump option in the xctl Debug Settings window.

You can then save the crashdumps from the raw / dev/pdedump to the DBC.Crashdumps database using CSP. However, be sure to contact TSC for assistance if this action is required.

Saving Crashloop PDE Crashdumps

In a Teradata RDBMS restart loop, new PDE crashdumps occur before the system can save old PDE crashdumps to the dump save area. If the PDE crashdumps accumulate in the dump area, they are not automatically saved until the Teradata RDBMS is up.
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