Pl sql if inserting updating
This means dynamic sampling will be applied to all unanalyzed tables.It also means that twice the number of blocks will be use to calculate statistics than were used in Oracle database 9i.
At the beginning of the peak workload window execute the following command: Oracle recommends gathering system statistics during a representative workload, ideally at peak workload time. System statistics are not automatically collected as part of the new statistics gather job (see the automatic statistics gathering job section below for more details).In Oracle database 10g the Optimizer operates under ALL_ROWS mode (CBO) and will use dynamic sampling to get statistics for any tables that do not have statistics and will use CBO.The other possible values are The parameter optimizer_dynamic_sampling has a new default value of 2 in Oracle Database 10g.When you gather system statistics in Oracle Database 10g they will override these initial values.To gather system statistics you should use DBMS_STATS. This Postgre SQL tutorial helps you understand Postgre SQL quickly.
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Oracle recommends that you analyze the data dictionary.
You can collect these statistics by using either the dbms_stats.gather_schema_stats or dbms_stats.gather_database_stats Oracle-supplied procedures, as shown here: procedures are NOT new in Oracle 10 g, but using them to collect data dictionary statistics is new, as there are some new parameters that are available with these procedures.
Also, 10g includes new features that enhance the generation of object level statistics within the database. Also new parameters has been added: and modified in Oracle database 10g.
This means the Optimizer will no longer operate under RULE mode (RBO) when a table has no statistics.
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