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The Evolution of Compression: Db2 12

December 19, 2017

This is the final post in my series on the evolution of compression with Db2 for z/OS. Read the previous posts covering Db2 8, Db2 9, Db2 10 and Db2 11.

With each release of Db2, enhancements have been made to improve compression performance, availability and scalability. An important change in Db2 12 is the introduction of the online deferred option, ALTER INDEX COMPRESS YES. This allows you to able compression for an index without causing an outage.

Large object (LOB) compression is also enhanced in Db2 12. This feature compresses the out-of-line portion of the LOB, which is the portion of the LOB stored in an auxiliary table space. It does this in 1-MB chunks. LOB requires the zEDC hardware feature.

Also new in this release is the capability to store COMPRESSRATIO in the catalog during a LOAD REPLACE. Because this provides the average compression ratio used by the Db2 utilities to calculate the required utility sort-work data set sizes, it can help you avoid an outage due to under sizing a sort-work data set.

Read more about Db2 12 for z/OS:

My goal with this series is to show you that compression has been a priority in Db2 development. By taking advantage of these capabilities, your enterprise can enjoy significant cost savings.

Posted December 19, 2017| Permalink

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