| The following hints can be used
in Oracle SELECT statements: |
| /*+ RULE */ |
-> Use rule-based optimization
(not available after Oracle7). |
| /*+ ALL_ROWS */ |
-> Use cost-based approach for
best throughput. |
| /*+ FIRST_ROWS */ |
-> Use cost-based approach for
best response time. |
| /*+ INDEX (table
[index])*/ |
-> Use an index scan of specified
table(and index if specified) |
| /*+ INDEX_ASC */ |
-> Use an ascending index search
of specified table |
| /*+ INDEX _DESC*/ |
-> Use a descending index search
of specified table |
| /*+ INDEX _COMBINE
(table [index]) */ |
-> Combines bitmapped indexes
of specified table |
| /*+ ROWID (table)
*/ |
-> Forces ROWID scan of specified
table |
| /*+ AND_EQUAL (table
[index])(table [index]...)*/ |
-> Forces (2 to 5) single column
index merge |
| /*+ USE_MERGE (table)
(table) ...*/ |
-> Use sort-merge-join of specified
tables |
| /*+ STAR */ |
-> Largest table joined last
using nested loops join |
| /*+ PARALLEL (table,
instances) */ |
-> Use PARALLEL query |
| /*+ NOPARALLEL (table)*/ |
-> Do not Use PARALLEL query
|
| /*+ PARALLEL_INDEX*/ |
-> Fast full index scan Parallelization |
| /*+ CACHE */ |
-> Fast full index scan Parallelization |
| /*+ PUSH_SUBQ */ |
-> When full table scanned,
retreived table blocks placed at most recently used LRU list
end. |
| /*+ USE_CONCAT */ |
-> When full table scanned,
retreived table blocks placed at most recently used LRU list
end. |
| /*+ HASH (table)
*/ |
-> When full table scanned,
retreived table blocks placed at least recently used LRU list
end. |
| /*+ FULL (table)
*/ |
-> Evaluate nonmerged subqueries
at earliest possible execution plan point |
| /*+ USE_CONCAT */ |
-> Force combined where clause
OR conditions transformation into UNION ALL compound query |
| /*+ HASH (table)
*/ |
-> Explicitly choose hash table
access method |
| /*+ FULL (table)
*/ |
-> Do a Full table scan |
| /*+ HASH_AJ (table)
*/ |
-> Transforms NOT IN subquery
to Hash antijoin |
| /*+ MERGE_AJ */ |
-> Transforms NOT IN subquery
to merge Antijoin |
| /*+ INDEX_FFS (table
index) */ |
-> Tells the optimizer to use
an index |
| /*+ CHOOSE */ |
-> Use cost if statisstics available
else use rule |
| /*+ CLUSTER (table)
*/ |
-> Forces a cluster scan of
the specified table. |
