Prior to your index creation effort, you may run PERFORMER to get a performance baseline for later comparison.
在进行创建索引的工作之前,您可以运行PERFORMER来获得性能基线,以便稍后进行比较。
2
If the index is being bypassed, then the RHS of the comparison should be type-cast.
如果会绕过索引,应该对比较表达式的RHS执行类型转换。
3
For comparison, Figure 3 illustrates the access plan where I forced the DB2 optimizer to ignore the index by adding the clause SELECTIVITY 1 to the predicate in the where clause.