Database parameter OPTIMIZER_DYNAMIC_STATISTICS
Date: Tue, 8 Oct 2019 14:48:02 +0000
Message-ID: <BL0PR11MB31699211FE22679E78B748E7F49A0_at_BL0PR11MB3169.namprd11.prod.outlook.com>
Hi all,
The Oracle Database SQL Tuning Guide for 19c states the following. It is also mentioned in one of the recently published 19c WP. However, I have not been able to find parameter OPTIMIZER_DYNAMIC_STATISTICS. It is not even listed in the Database Reference Guide for 19c. Was it a document error?
Thanks,
Amir
12.3.1 About Dynamic Statistics Levels
The dynamic statistics level controls both when the database gathers dynamic
statistics, and the size of the sample that the optimizer uses to gather the statistics.
Set the dynamic statistics level using either the OPTIMIZER_DYNAMIC_SAMPLING
initialization parameter or a statement hint.
Note:
Dynamic statistics were called dynamic sampling in releases earlier than
Oracle Database 12c Release 1 (12.1).
The following table describes the levels for dynamic statistics. Note the following:
* If OPTIMIZER_DYNAMIC_STATISTICS is TRUE, and if dynamic statistics are not
disabled, then the database may choose to use dynamic statistics when a SQL
statement uses parallel execution.
* If OPTIMIZER_ADAPTIVE_STATISTICS is TRUE
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