WebFeb 24, 2010 · That said, Oracle's estimate of cardinality is a primary driver in execution plan. A 10053 trace analysis (Jonathan Lewis' Cost-Based Oracle Fundamentals book has … http://www.dba-oracle.com/t_sql_hints_tuning.htm
sql - Will Oracle optimizer use multiple Hints in the same SELECT ...
WebFor example, run the following SQL statement to set the optimizer version to 12.1.0.2 : Copy SQL> ALTER SYSTEM SET OPTIMIZER_FEATURES_ENABLE='12.1.0.2'; The preceding statement restores the optimizer functionality that existed in Oracle Database 12c Release 1 (12.1.0.2). "Managing SQL Plan Baselines" WebNov 3, 2016 · a) put the hint in, either directly or via baseline/profile/etc to solve the problem in the short term b) investigate why the optimizer did not derive the correct plan in the first … five swords tarot guide
A Beginner’s Guide to Optimizer Hints - Simple Talk
WebThe left-deep join tree can be enforced with the following hints: 1 2 3 4 5 6 7 /*+ LEADING ( t1 t2 t3 t4 ) USE_HASH ( t2 ) USE_HASH ( t3 ) USE_HASH ( t4 ) NO_SWAP_JOIN_INPUTS ( t2 ) NO_SWAP_JOIN_INPUTS ( t3 ) NO_SWAP_JOIN_INPUTS ( t4 ) */ We could have also written USE_HASH ( t4 t3 t2 ) instead of three separate hints. WebNov 3, 2016 · I prefer LEADING to ORDERED, but with *any* hint, my thought process is normally: a) put the hint in, either directly or via baseline/profile/etc to solve the problem in the short term b) investigate why the optimizer did not derive the correct plan in the first place. If (b) can be solved, then take the necessary action and remove the hint. WebOct 9, 2024 · LEADING With this hint, you can decide which table will be the driving table out of the two joined tables. This is very important when you incorrectly write a query, where the small table is a driving table and the large one is a joined table or vice versa. The order matters a lot and might dramatically change the plan. /** * can i watch roadkill on my tv through xumo