关于PCTFREE、PCTUSED的设置

d.c.b.a

[quota]
The sum of PCTFREE & PCTUSED should be less than 100. I think it should be in the range of 80 - 90, but that is a "gut feel" with little evidence. PCTUSED really controls how quickly a block goes back on the free list. This is a pretty complex topic, but can have great impact on the performance of inserts to the table.
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应当对insert有影响,而不是对delete有影响,一个块中尽量多放一些记录,应当对delete有利.

xdfzmh

最初由 d.c.b.a 发布
[B][quota]
The sum of PCTFREE & PCTUSED should be less than 100. I think it should be in the range of 80 - 90, but that is a "gut feel" with little evidence. PCTUSED really controls how quickly a block goes back on the free list. This is a pretty complex topic, but can have great impact on the performance of inserts to the table.
[/quota]

应当对insert有影响,而不是对delete有影响,一个块中尽量多放一些记录,应当对delete有利. [/B]

对pctused 设置过大，会增加insert process cost，但官方的文档中说，设置pctused=60 是delete process cost 是最小的。