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本帖最后由 wolfop 于 2012-8-26 11:18 编辑
liqy103 发表于 2012-8-24 15:18 ![]()
It becomes worse situation when paralleled by application itself, e.g. we have 30 streams to run sam ...
That is a wrong usage to deal mass data in 11GR2. I have seen many this wrong way in production. Why not use parallel query in one query not partition by the application just like most MPP database.
Another simple way may help is to set paralle_degree_policy to AUTO, but you need to do some test and IO calibrate.
Another point is this is not a 11G2R new feature, in 10GR2 there are also direct path reads. You shoud try to find why the optimizer choose direct path read.
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