Eulogy
发表于 2025-3-28 14:41:07
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ADOPT
发表于 2025-3-28 18:49:54
Joinsed subqueries, or expressions involving the . or . operators. If there is more than one row source then the rows produced by these row sources need to be ., there being one less join operation than there are row sources. In Chapter 1 I covered the various different syntactic constructs for joins. Th
N斯巴达人
发表于 2025-3-29 02:29:21
Final State Optimization transformation and final state optimization. In this chapter I will cover final state optimization, and transformations will be the focus of Chapter 13. Put another way, this chapter looks at how the CBO evaluates different candidate execution plans after any query transformations have been perform
南极
发表于 2025-3-29 06:04:27
Optimizer Transformationsuery‘s meaning. For all but the most trivial of queries the CBO will consider a number of such transformations, sometimes estimating costing, to determine the best SQL statement on which to perform the final state optimization that we just covered in Chapter 12. This chapter is dedicated to the topi
DOSE
发表于 2025-3-29 08:17:03
Why Do Things Go Wrong?d then something works out how to do it. In the case of an Oracle database, that “something” is the CBO, and it should devise an appropriate execution plan for you. In theory you shouldn’t have to worry about getting incorrect results and you shouldn’t have to worry about performance. Since you are
荒唐
发表于 2025-3-29 14:54:56
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Ejaculate
发表于 2025-3-29 18:57:29
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Chronic
发表于 2025-3-29 21:31:08
Management von Familien-Unternehmen,ways in which B-tree and bitmap indexes can be used to generate ROWIDs. The last three sections in this chapter discuss the much maligned full table scan, the little understood . and . operators, and for completeness cluster access, which most people will never need to use.
高歌
发表于 2025-3-30 00:17:07
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抱负
发表于 2025-3-30 06:24:55
https://doi.org/10.1007/978-3-662-25664-0c of optimizer transformations; you will see that there are a bewildering number of such transformations. Although not all optimizer transformations are included in this chapter, the vast majority that you will encounter in your day-to-day life are, as well as some that you will rarely encounter.