Saturday, June 4, 2011

what are different types of journals in teradata?

There are  3 different types of journals available in Teradata. They are

1. Transient Journal  - This maintains current transaction history. Once the query is successful it deletes entries from its table .  If the current query transaction fails, It rolls back data from its table.

2. Permanent Journal  - This is defined when a table is created.  It can store BEFORE or AFTER image of tables. DUAL copies can also be stored. Permanent Journal maintains Complete history of table.

3.Down AMP recovery Journal (DARJ)  - This journal activates when the AMP which was supposed to process goes down.  This journal will store all entries for AMP which went down.  Once that AMP is up, DARJ copies all entries to that AMP and makes that AMP is sync with current environment.

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