On-line Maintenance

Published 10 February 2004

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Authors: Whei-Jen Chen


DB2 UDB V8 has several new on-line database maintenance features. These features can improve both the database availability and performance.


Online Maintenance

DB2 UDB V8 introduces several new on-line maintenance features to enhance the database availability:

  • In-place Reorg: Read and Write to the table is allowed while the table is being reorganized.
  • On-line Index : With the REORG INDEX command, reading and writing to the table is allowed, while the index is being created;
read and write access is permitted to the table and the index, while the index is being reorganized.
  • On-line Load: Has two modes: one occurs when the tablespace is on-line but the table being loaded is off-line;
the other occurs when the tablespace is on-line and the table being loaded is available for read.

The FixPak 4 adds another on-line maintenance feature - On-line Import. The on-line mode provides better availability of the target table and potentially increases the performance of the import utility. The import utility now supports two locking modes: off-line mode, (ALLOW NO ACCESS), and on-line mode, (ALLOW WRITE ACCESS). Off-line mode is the default.

On-line import is especially valuable when range-clustered tables (RCT) are used. Load into RCTs is not supported, and therefore performing 4 multiple concurrent imports into a single target table is the most efficient 4 way to populate the database using supported DB2 utilities.

This new feature is also supported in the API db2Import.

Special Notices

This material has not been submitted to any formal IBM test and is published AS IS. It has not been the subject of rigorous review. IBM assumes no responsibility for its accuracy or completeness. The use of this information or the implementation of any of these techniques is a client responsibility and depends upon the client's ability to evaluate and integrate them into the client's operational environment.

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