WebThe statistics are mainly based on groups of index elements of the same value. In a primary key, every index is unique, so every group size is one. In a non-unique index, you may have multiple keys with the same value. A worst-case example would be having large groups with the same value, for example an index on a boolean field. WebNov 23, 2013 · 1 Answer. Sorted by: 3. The difference is, gathering statistics refreshes the metadata about the current index whereas dropping and re-creating the index is, er, dropping and re-creating the index. Perhaps it is easy to understand the difference with …
Gather Statistics in Oracle - DBA Genesis Support
WebOracle Optimizer determines the cost of each execution plan based on database, schema, table and other statistics. The changes inside database result in stale statistics. As a … WebSep 17, 2010 · Using this option is equivalent to running gather_table_stats plus running gather_index_stats for each index on the table. If you always want indexes analyzed when running gather_table_stats you can use the set_database_prefs, set_global_prefs, or set_table_prefs, to always include indexes when gather_table_stats is executed. cheshire west and chester hs2
Gather Statistics in Oracle - DBA Genesis Support
WebNov 1, 2010 · However if we use gather_index_stats statistics shows number of leaf blocks equals number of leaf blocks that actually has the data. Here is the illustration for the same. Create a table. SQL> create table t1 pctfree 99 pctused 1 2 as 3 select rownum id, 4 trunc(100 * dbms_random.normal) val, 5 rpad('X',100) padding 6 from all_objects where ... WebTable 63-33 GATHER_INDEX_STATS Procedure Parameters. Parameter Description ; ownname : Schema of index to analyze. indname : Name of index. partname : Name of … WebAccording to the documentation, "Use the constant DBMS_STATS.AUTO_CASCADE to have Oracle determine whether index statistics are to be collected or not." But it seems like AUTO_CASCADE will always gather index statistics, even when it obviously does not need to. SQL> --Create table SQL> create table statistics_test (a number, b number, c … good mc clients