The DB2 9.5 optimizer USES both type of indexes to optimize the queries and help selecting the best plan for query execution.

DB 2 9.5优化器使用两种类型的索引来优化查询，并帮助选择最佳的查询执行计划。

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When the query is prepared, the database will analyze, compile and optimize it's plan for executing the query.

当查询准备好后，数据库将分析、编译和优化执行该查询的计划。

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By using active and passive management for ORACLE and optimize tools like SQL TRACE EXPLAIN PLAN and ORACLE OPTIMIZER, the query response time is shortened and the efficiency is improved.

通过对Oracle性能的主动和被动管理，以及优化工具SQL Trace、EXPLAIN PLAN和优化器的使用，缩短了数据仓库用户查询响应的时间，提高了查询效率。

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