Re: Unlock the power of using Oracle Optimizer Hints to tune SQL statements

On Sunday, February 18, 2018 at 10:28:52 PM UTC+8, Michel Cadot wrote:
> <tracyto41_at_gmail.com> a écrit dans le message de news: 203ad84c-7b27-4860-a858-fd33cf9d9b7a_at_googlegroups.com...
>
> >>> In contrast, using hints to tune a SQL is relatively safer,
>
>
>
> This is wrong and Jonathan Lewis definitively demonstrated it more than a decade ago, demonstration which is still valid in the
> current versions and for all the futures ones.
>
> You should take advantage to read Oracle documentation which states:
> https://docs.oracle.com/database/121/SQLRF/sql_elements006.htm#SQLRF00219
> https://docs.oracle.com/en/database/oracle/oracle-database/12.2/sqlrf/Comments.html#GUID-D316D545-89E2-4D54-977F-FC97815CD62E
>
> <quote>
> Hints should be used sparingly, and only after you have collected statistics on the relevant tables and evaluated the optimizer plan
> without hints using the EXPLAIN PLAN statement. Changing database conditions as well as query performance enhancements in subsequent
> releases can have significant impact on how hints in your code affect performance.
> </quote>
>
> And you still did not answer to the pertinent remarks made by Nuno, Mladen and Ed in one of your previous threads about your
> "product".
> Go away ignorant spammer!
>
> Regards
> Michel

If collect statistics works, you should do it first. We are talking SQL tuning to make a SQL run faster. Only hints application can be used in SQL Patches or SQL Plan baselines, it is very important in source free SQL tuning. Received on Thu Mar 15 2018 - 03:29:10 CET