Optimizer

Optimizer

Oracle LIKE predicate and cardinality estimations

Submitted by fpachot on Sun, 11/11/2018 - 21:01

There are not many ways to access efficiently to table rows. Either you want lot of them, because your predicate is not very selective, and you read the whole table in the fastest you can do. This is Table Full Scan. Or you use a structure that gives you access to the subset of rows you need. There are mostly two structures for that: sort and hash.

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