Scan Operation Hints
Function
These hints specify a scan operation, which can be tablescan, indexscan, or indexonlyscan.
Syntax
[no] tablescan|indexscan|indexonlyscan(table [index])
Parameter Description
no indicates that the specified hint will not be used for a join.
table specifies the table to be scanned. You can specify only one table. Use a table alias (if any) instead of a table name.
index indicates the index for indexscan or indexonlyscan. You can specify only one index.
NOTE:
indexscan and indexonlyscan hints can be used only when the specified index belongs to the table.
Scan operation hints can be used for row-store tables, column-store tables, OBS tables, and subquery tables.
Example
To specify an index-based hint for a scan, create an index named i on the i_item_sk column of the item table.
create index i on item(i_item_sk);
Hint the query plan in Example as follows:
explain
select /*+ indexscan(item i) */ i_product_name product_name ...
item is scanned based on an index. The optimized plan is as follows:
