16.10 - RECOVERY LOG CHECKPOINT - Teradata Unity

Teradata Unity User Guide

Product
Teradata Unity
Release Number
16.10
Published
January 2018
Language
English (United States)
Last Update
2018-03-29
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Purpose

Before starting a large ETL job, ETL operators can manually request a Recovery Log Checkpoint, instead of relying on the Sequencer automatic checkpoint process. The Recovery Log Checkpoint can also be set up at a time with low database activity so that in-flight transactions do not interfere with the checkpoint process. Similar to the automatic checkpoint process, the Sequencer must wait for all in-flight transactions to close. The default timeout is 90 seconds. If the transactions do not close, the Sequencer fails the checkpoint process and creates an error. The HaltTimeout parameter controls the default time-out value.

When the timeout setting is used, all new transactions started by clients are held until the timeout expires or the checkpoint occurs. This may cause delays in processing client requests.

Syntax

RECOVERY LOG CHECKPOINT [NOW | <timeout>];

Parameters

NOW

The attempt does not wait. If there are any in-flight transactions, the checkpoint fails immediately.

<timeout>

The attempt waits the specified timeout for in-flight transactions to complete. This overrides the timeout specified in the HaltTimeout parameter.

Examples

The following example attempts to obtain a recovery log checkpoint. The attempt fails immediately if there are any in-flight transactions.
unityadmin -u admin -P admin -e 'recovery log checkpoint now'
The following example attempts to obtain a recovery log checkpoint. It uses a timeout of 60 seconds instead of the HaltTimeout parameter.
unityadmin -u admin -P admin -e 'recovery log checkpoint 60'
The following example attempts to obtain a recovery log checkpoint. It uses the timeout specified by the HaltTimeout parameter (90 seconds by default).
unityadmin -u admin -P admin -e 'recovery log checkpoint'