Updating statistics in oracle
2) By default, the UPDATE STATISTICS statement uses only a sample of records of the table.
Using UPDATE STATISTICS WITH FULLSCAN will scan the entire table.
You probably have jobs/maintenance plans setup to update statistics.
But if you ever ran into an issue with slow query performance and wanted to do a quick check on the statistics for ALL indexes in the database, you would use either dbcc show_statistics or sp_autostats. Here is a way to do this for the entire database using TSQL query, — For SQL 2005/SQL 2008 select as 'Object ID', isnull(a.name,'Heap') as 'Index Name', as 'Table Name', stats_date (id,indid) as stats_last_updated_time from sys.sysindexes as a inner join sys.objects as b on = b.object_id where = 'U': Rowmodctr values displayed above are not entirely reliable starting with SQL 2005 onwards.
Assess your circumstances and develop a plan for keeping your statistics up to date, so that the query optimizer can do its job.
One of the questions I was asked recently while speaking at the Los Angeles SQL Server Professionals Group and the Orange County SQL Server User Group (*) was regarding the order in which jobs like rebuilding indexes or updating statistics should be executed as part of the database maintenance activities.
NOTE In high-volume environments, you can update statistics on a restored database, and then import them into the production server using the optdiag utility, but that’s a lot more work.
Options for updating statistics ASE provides a number of options for updating statistics, depending on the specific needs you have.
If you’ve ever had a straightforward application with small tables, but terrible performance, or a complex application with erratic performance, or a seemingly well-performing application that suddenly became very slow, there’s a good chance the problem was out-of-date statistics.
To update information about the distribution of key values in specified indexes, for all columns in an index, table, or partition, the syntax is: update statistics table_name
You can pipe this to a temp table and choose to update statistics on only these tables.
Rebuilding indexes does not update any column statistics.