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Query workloads in Figure 8-23 show 0 - 10% range of CPU time reduction with Db2 12 compared to Db2 11. These workloads fall into two categories: Simple queries and queries where most of the processing is because of data scanning. The data scanning queries are good candidates for IBM Db2 Analytics Accelerator for z/OS and were generally not targeted for Db2 12 performance improvements. Fewer queries in this set of workloads see access path changes with Db2 12. 

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## 8.7.2 Access path change and performance improvement 

In the IBM query workloads that were described in this section, the queries with new access paths tended to see larger improvements compared to the queries without access path changes. 

Typical CPU and elapsed time reduction from the queries with new access paths is 10 - 99%, while the queries without access path changes resulted in the improvements of 0 - 20%. 

Many Db2 users tend to use APREUSE for their static SQL statements to keep their known stable access paths during the migration of Db2. This approach is still recommended to reduce the risk from the migration. 

However, after the successful migration of Db2 12, we strongly recommend rebinding without APREUSE in a controlled manner to use the full potential of Db2 12. 

