|
variables. |
| DRIVING_SITE |
The DRIVING_SITE hint forces query execution to be done for the table at a different site than that selected by Oracle |
| DYNAMIC_SAMPLING |
The DYNAMIC_SAMPLING hint lets you control dynamic sampling to improve server performance by determining more accurate predicate selectivity and statistics for tables and indexes. You can set the value of DYNAMIC_SAMPLING to a value from 0 to 10. The higher the level, the more effort the compiler puts into dynamic sampling and the more broadly it is applied. Sampling defaults to cursor level unless you specify a table. |
| SPREAD_MIN_ANALYSIS |
This hint omits some of the compile time optimizations of the rules, mainly detailed dependency graph analysis, on spreadsheets. Some optimizations such as creating filters to selectively populate spreadsheet access structures and limited rule pruning are still used. (from Oracle 10g) |
| Hints with unknown status |
| MERGE_AJ |
The MERGE_AJ hint transforms a NOT IN subquery into a merge anti-join to access the specified table. The syntax of the MERGE_AJ hint is MERGE_AJ(table) where table specifies the name or alias of the table to be accessed.(depricated in Oracle 10g) |
| AND_EQUAL |
The AND_EQUAL hint explicitly chooses an execution plan that uses an access path that merges the scans on several single-column indexes. The syntax of the AND_EQUAL hint is AND_EQUAL(table index index) where table specifies the name or alias of the table associated with the indexes to be merged. and index specifies an index on which an index scan is to be performed. You must specify at least two indexes. You cannot specify more than five. (depricated in Oracle 10g) |
| STAR |
The STAR hint forces the large table to be joined last using a nested loops join on the index. The optimizer will consider different permutations of the small tables. (depricated in Oracle 10g) |
| BITMAP |
Usage: BITMAP(table_name index_name) Uses a bitmap index to access the table. (depricated ?) |
| HASH_SJ |
Use a Hash Anti-Join to eva luate a NOT IN sub-query. Use this hint in the sub-query, not in the main query. Use this when your high volume NOT IN sub-query is using a FILTER or NESTED LOOPS join. Try MERGE_AJ if HASH_AJ refuses to work.(depricated in Oracle 10g) |
| NL_SJ |
Use a Nested Loop in a sub-query. (depricated in Oracle 10g) |
| NL_AJ |
Use an anti-join in a sub-query. (depricated in Oracle 10g) |
| ORDERED_PREDICATES |
(depricated in Oracle 10g) |
| EXPAND_GSET_TO_UNION |
(depricated in Oracle 10g)
? |