Web- Oracle cardinality hint tips - Oracle estimate table join cardinality Greg Rahn of Oracle Corporation notes a great example of using the gather_plan_statistics hint: As a first step of triage, I would suggest executing the query with a GATHER_PLAN_STATISTICS hint followed by a call to DBMS_XPLAN.DISPLAY_CURSOR. WebSELECT product_id, CARDINALITY(ad_textdocs_ntab) cardinality FROM print_media ORDER BY product_id; PRODUCT_ID CARDINALITY ----- ----- 2056 3 2268 3 3060 3 3106 3 ...
Oracle Dynamic Sampling tips
WebJan 4, 2024 · Keeping aside the choice of the most appropriate hint for your query (if any), the order you write the table names/aliases in the USE_NL hint does not matter. According to Oracle documentation: Note that USE_NL (table1 table2) is not considered a multi-table hint because it is a shortcut for USE_NL (table1) and USE_NL (table2) http://www.oracle-developer.net/display.php?id=427 how much snow fell in jamestown ny
Cardinality hint for collections in Oracle 10g. - Oracle Forums
WebSep 13, 2024 · There are a couple of hints and hint patterns, but I suggest that you keep it simple: Copy code snippet select /*+ dynamic_sampling (5) */ count (*) from items where item_type_code like '%A1%'; You can use a SQL patch to apply hints to individual SQL statements, avoiding the need to change the application: Copy code snippet WebJul 20, 2024 · If cardinality estimates are inaccurate, then the calculated costs are likely to be inaccurate too. The resulting execution plan might be suboptimal because it is based on incorrect or missing information. Still, it is essential to remember that this does not mean that a bad execution plan is certain. WebJun 10, 2015 · SELECT * FROM ( SELECT DISTINCT * FROM ( SELECT TransactionID FROM WOWDev.QueryLog WHERE UPPER (UserName)=UPPER ('xyz') AND TransactionID IS NOT NULL ORDER BY TransactionID DESC ) WHERE ROWNUM<=1e100 -- fake ROWNUM check! this gets us on the fast path ) WHERE ROWNUM<=50 Here's the optimizer plan. how do u get totems of undying in minecraft