It is possible to transfer statistics between servers allowing consistent execution plans between servers with varying amounts of data.
The stats are removed using the Locking stats can be very useful to prevent automated jobs from changing them.
This is especially useful with tables used for ETL processes.
parameter was often used when gathering stats from large segments to reduce the sample size and therefore the overhead of the operation.
In Oracle 9i upwards, we also had the option of letting Oracle determine the sample size using the constant is the preferred (and default) sample size as the mechanism for determining the actual sample size has been improved.
Fixed object stats are not gathered automatically, so you need to gather them manually at a time when the database is in a representative level of activity.
Major changes to initialization parameters or system activity should signal you to gather fresh stats, but under normal running this does not need to be done on a regular basis.It is worth spending some time checking the documentation relevant to your version.Table statistics can be gathered for the database, schema, table or partition.If the stats are gathered when the tables are empty, they will not reflect the real quantity of data during the load process.Instead, either gather stats each time the data is loaded, or gather them once on a full table and lock them.When a valid SQL statement is sent to the server for the first time, Oracle produces an execution plan that describes how to retrieve the necessary data.