1.229 OPTIMIZER_DYNAMIC_SAMPLING

OPTIMIZER_DYNAMIC_SAMPLING controls both when the database gathers dynamic statistics, and the size of the sample that the optimizer uses to gather the statistics.

Property Description

Parameter type

Integer

Default value

If OPTIMIZER_FEATURES_ENABLE is set to 10.0.0 or higher, then 2

If OPTIMIZER_FEATURES_ENABLE is set to 9.2.0, then 1

If OPTIMIZER_FEATURES_ENABLE is set to 9.0.1 or lower, then 0

Modifiable

ALTER SESSION, ALTER SYSTEM

Modifiable in a PDB

Yes

Range of values

0 to 11

Basic

No

Note:

Dynamic statistics were called dynamic sampling in releases earlier than Oracle Database 12c Release 1 (12.1).

If the value of OPTIMIZER_DYNAMIC_SAMPLING is set to 11, the OPTIMIZER_FEATURES_ENABLE setting has no effect on the OPTIMIZER_DYNAMIC_SAMPLING setting.

See Also:

Oracle Database SQL Tuning Guide for detailed information about the values (0 – 11) that can be set for the OPTIMIZER_DYNAMIC_SAMPLING parameter.