Contents
(hint-list)=
Hint list
The available hints are listed below.
| Group | Format | Description |
|:------|:-------|:------------|
| Scan method | SeqScan(table)
| Forces sequential scan on the table. |
| | TidScan(table)
| Forces TID scan on the table. |
| | IndexScan(table[ index...])
| Forces index scan on the table. Restricts to specified indexes if any. |
| | IndexOnlyScan(table[ index...])
| Forces index-only scan on the table. Restricts to specified indexes if any. Index scan may be used if index-only scan is not available. |
| | BitmapScan(table[ index...])
| Forces bitmap scan on the table. Restricts to specified indexes if any. |
| | IndexScanRegexp(table[ POSIX Regexp...])
IndexOnlyScanRegexp(table[ POSIX Regexp...])
BitmapScanRegexp(table[ POSIX Regexp...])
| Forces index scan, index-only scan (For PostgreSQL 9.2 and later) or bitmap scan on the table. Restricts to indexes that matches the specified POSIX regular expression pattern. |
| | NoSeqScan(table)
| Forces to not do sequential scan on the table. |
| | NoTidScan(table)
| Forces to not do TID scan on the table.|
| | NoIndexScan(table)
| Forces to not do index scan and index-only scan on the table. |
| | NoIndexOnlyScan(table)
| Forces to not do index only scan on the table. |
| | NoBitmapScan(table)
| Forces to not do bitmap scan on the table. |
| Join method| NestLoop(table table[ table...])
| Forces nested loop for the joins on the tables specified. |
| | HashJoin(table table[ table...])
| Forces hash join for the joins on the tables specified. |
| | MergeJoin(table table[ table...])
| Forces merge join for the joins on the tables specified. |
| | NoNestLoop(table table[ table...])
| Forces to not do nested loop for the joins on the tables specified. |
| | NoHashJoin(table table[ table...])
| Forces to not do hash join for the joins on the tables specified. |
| | NoMergeJoin(table table[ table...])
| Forces to not do merge join for the joins on the tables specified. |
| Join order | Leading(table table[ table...])
| Forces join order as specified. |
| | Leading(<join pair>)
| Forces join order and directions as specified. A join pair is a pair of tables and/or other join pairs enclosed by parentheses, which can make a nested structure. |
| Behavior control on Join | Memoize(table table[ table...])
| Allows the topmost join of a join among the specified tables to Memoize the inner result. Not enforced. |
| | NoMemoize(table table[ table...])
| Inhibits the topmost join of a join among the specified tables from Memoizing the inner result. |
| Row number correction | Rows(table table[ table...] correction)
| Corrects row number of a result of the joins on the tables specified. The available correction methods are absolute (#