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Message Posted: Wed, 29 Jan 2014 @ 10:12:05 GMT
| Subj: | | Re: Inefficient LEFT JOIN execution plan |
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| From: | | Frydryszak, Marek |
Optimizer is not enough smart to notice, that executing 3 joins instead of 2 may by faster.
Two logical joins are always performed as 2 join steps - optimizer decides only on sequence and algorithms.
Generally you are right - such kind of optimizations would be great. But rather difficult to implement. Let's imagine how many possible plans
should be considered for SQL with 40 joins ...
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