Best Practices for Gathering Optimizer Statistics ... - Oracle

Best Practices for Gathering Optimizer Statistics with Oracle Database 12c Release 2 O R A C L E W H I T E P A P E R | J U N E 2 0 1 7 BEST Practices FOR Gathering Optimizer Statistics WITH Oracle DATABASE 12C RELEASE 2 Table of Contents Introduction 1 How to Gather Statistics 1 When to Gather Statistics 7 Assuring the Quality of Optimizer Statistics 11 Gathering Statistics More Quickly 13 When Not to Gather Statistics 16 Gathering Other Types of Statistics 18 Conclusion 20 References 21 1 Introduction The Oracle Optimizer examines all of the possible plans for a SQL statement and picks the one with the lowest cost, where cost represents the estimated resource usage for a given plan.

the behavior of auto statistics gathering where necessary. You can specify a particular non-default parameter value for an individual DBMS_STATS.GATHER_*_STATS command, but the recommended approach is to override the defaults DBMS_STATS.SET_*_PREFSwhere necessary using “targeted” procedures.

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  Oracle, Practices, Statistics, Procedures, Auto, Optimizers, Gathering, Practices for gathering optimizer statistics

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