Database Reference
In-Depth Information
------------------------------------------------------------------
Index Scan
using idx on history (cost=0.57..8.59 rows=1
width=46)
Index Cond: (history_id = 1000)
Planning time: 0.146 ms
(3 rows)
In the preceding hints example, the planner culls the index scan for the query. If we
don't want to utilize the index scan, then we can incapacitate the index scan using
the following statement:
warehouse_db=# SET enable_indexscan = FALSE;
The result of using the preceding statement is as follows:
warehouse_db=# EXPLAIN SELECT * FROM record.history WHERE
history_id = 1000;
QUERY PLAN
------------------------------------------------------------------
Bitmap Heap Scan
on history (cost=4.58..8.59 rows=1 width=46)
Recheck Cond: (history_id = 1000)
-> Bitmap Index Scan on idx (cost=0.00..4.58 rows=1 width=0)
Index Cond: (history_id = 1000)
Planning time: 0.152 ms
(5 rows)
The following features can be enabled or disabled:
•
enable_bitmapscan
•
enable_hashjoin
•
enable_indexscan
•
enable_mergejoin
•
enable_seqscan
•
enable_tidscanenable_hashagg
•
enable_indexonlyscan
•
enable_material
•
enable_nestloop
•
enable_sort