Oracle Database 11g introduced a new sampling algorithm that is hash based and provides deterministic statistics. This new approach has the accuracy close to a 100% sample but with the cost of, at most, a 10% sample. The new algorithm is used when ESTIMATE_PERCENT is set to AUTO_SAMPLE_SIZE (the default)
It is highly recommended that from Oracle Database 11g onward you let ESTIMATE_PRECENT default.
The METHOD_OPT parameter controls the creation of histograms during statistics collection. Histograms are a special type of column statistic created when the data in a table column has a non-uniform distribution.
A unique column will not have a histogram created on it if it is only seen in equality predicates.
Domain Indexes -- 4 : CTXRULE Index - I have earlier provided simple demonstrations of CONTEXT and CTXCAT Indexes. A CTXRULE Index can be used to build a Document Classification application. T...
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