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Barry Fritchman <barry.fritchman@hp.com>
committed
on 15 Dec 14
Automated collection of necessary statistics
When the optimizer requests a histogram for a given column, and that
histogram does not exist, … Show more
Automated collection of necessary statistics

When the optimizer requests a histogram for a given column, and that

histogram does not exist, it may (depending on the cqds in effect) register

a request for the histogram to be created at a later time, or utilize a

small sample to generate a rudimentary histogram on the fly. In either

case, when a subsequent Update Statistics statements specifies the ON

NECESSARY COLUMNS clause, any column of the target table that has been

the subject of one of these actions will have a bona fide histogram

created.

blueprint ustat-automation

Change-Id: Ieceac3e1d84bf8091a5bf340dc1739a447ad2436

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