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rw30
Starting Member
3 Posts |
 Posted - 2009-09-24 : 16:53:27
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I thought that the operation with highest NodeID is the first one, then every next step got the NodeID decremented by 1.Now, after I used the option (force order) hint it looks I was wrongmy query is:select *into tmp_tabfrom assoc_fac1_fac2 inner join fac1 on assoc_fac1_fac2.fac1_key = fac1.fac1_keyinner join dim1 on fac1.dim1_key = dim1.dim1_keyoption (force order);query plan :[URL=http://img38.imageshack.us/i/planforceorder.jpg/] [/URL]where:table scan of assoc_fac1_fac2 has nodeID=4table scan of fac1 has nodeID=5table scan of dim1 has nodeID=7so is there any correlation between nodeID value and order of the operations taken during executing the query or not ?if no, how can be the order of operations read from XML plan ? or should I just use text plan for determining order ?regards,rw30 |
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robvolk
Most Valuable Yak
15732 Posts |
Posted - 2009-09-24 : 17:13:12
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quote:
so is there any correlation between nodeID value and order of the operations taken during executing the query or not
I don't know if there is, but if I can ask, why is that important? The optimizer processes the query on a cost basis, and will try to minimize it (choose the plan with minimum cost). I can understand if you're comparing the plans generated by using various hints, but whether each node on the plan is actually executed in that order doesn't seem as relevant. |
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what's order of operations in query exec. plan ?