So we added indexes on those joining columns and from the following query execution plan, we can see the query cost is greatly reduced.

因此，我们在这些连接列上添加了索引，从下列查询执行计划中我们可以看到，查询成本减少了很多。

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Though we did not sort this list, we immediately can see the query with the highest execution time is 41.844554.

虽然我们没有排序该列表，但可以立即看到具有最高执行时间的查询是41.844554。

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In Figure 2, you see three different execution plans for this query (simplified output from db2exfmt).

在图2中可以看到该查询的不同执行计划(简化了db 2 exfmt的输出)。

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