Re: Option NOLOGGING for indexes

Howard J. Rogers wrote:

> You're missing the fact that NOLOGGING *never* applies to ordinary
> inserts, deletes and updates. Therefore, in the context of Indexes, it
> applies only for the very creation of the index, not its subsequent
> maintenance by virtue of modifications being done to the table.

Yep. Basically NOLOGGING means that the CREATE statement is not recorded for redo and archive loggging. Results in some increase in performance as it is unrecoverable operation.

It will help if some people with questions like this, actually bother to read the Oracle SQL Reference manual:
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In NOLOGGING mode, data is modified with minimal logging (to mark new extents INVALID and to record dictionary changes). When applied during media recovery, the extent invalidation records mark a range of blocks as logically corrupt, because the redo data is not fully logged. Therefore, if you cannot afford to lose this table, you should take a backup after the NOLOGGING operation.

The size of a redo log generated for an operation in NOLOGGING mode is significantly smaller than the log generated with the LOGGING attribute set.

If the database is run in ARCHIVELOG mode, media recovery from a backup taken before the LOGGING operation restores the table. However, media recovery from a backup taken before the NOLOGGING operation does not restore the table.

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Billy