Re: Optimizer and ANSI Joins

Interesting, thank you Sayan.

I had not previously seen that function, at least not that I can remember.

Nonetheless, there is usually some kernel of truth behind rumors such as this, and I am curious as to what that is.

Jared Still
Certifiable Oracle DBA and Part Time Perl Evangelist Principal Consultant at Pythian
Pythian Blog http://www.pythian.com/blog/author/still/ Github: https://github.com/jkstill

On Tue, Jan 29, 2019 at 9:50 AM Sayan Malakshinov <xt.and.r_at_gmail.com> wrote:

> Hi Jared,
>
> Of course, cbo understand ansi joins, because it transforms them into own
> syntax :)
> (with some nuances like full outer join(it has now native full outer join,
> but not in syntax yet) or outer join to more than one table before 12c)
>
> You can check 10053 trace or dbms_sql2.expand_sql_text
> (DBMS_UTILITY.expand_sql_text since 12c)
>
> вт, 29 янв. 2019 г., 20:10 Jared Still jkstill_at_gmail.com:
>
>> Hello All:
>>
>> Something I have heard a few times is that the Oracle Optimizer does not
>> understand ANSI joins, and that ANSI joins are first converted to some
>> legacy format before the optimizer processes them.
>>
>> Does anyone here know if there is any truth in this?
>>
>> Some things that come to mind:
>>
>> - perhaps it was true at one time (9i)
>> - only partially true
>> - a blatant lie started by a SQL Server Fan.
>>
>> OK, that last one was uncalled for, but a little humor is necessary
>> sometimes :)
>>
>> I have googled around for this a bit, but find nothing that really
>> discusses the topic.
>>
>> Thanks,
>>
>> Jared Still
>> Certifiable Oracle DBA and Part Time Perl Evangelist
>> Principal Consultant at Pythian
>> Pythian Blog http://www.pythian.com/blog/author/still/
>> Github: https://github.com/jkstill
>>
>>
>>

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