Re: Performance Diff between 12 and 19

Hi Clay!

May I ask why are you testing with the base version? Current 19c is 19.6, to go to 19.7 in April. There are lots of fixed bugs. I will run your test on both 12.2 and 19.6 over the weekend and will let you know the result. However, I don't have 19.3 version, I applied the latest RUB.

Regards

On 3/12/20 12:31 PM, Clay Jackson (cjackson) wrote:
>
> Good day!
>
> We’re doing some testing of Oracle 19C for our products, and working
> with a customer who saw some significant differences with performance
> of sequences between Oracle 12.2.0 and 19.3.0.  We’ve looked at plans
> (identical) and trace files (no differences other than expected 12 vs
> 19).    Before we open an SR, I was wondering if anyone here has seen
> similar issues or can give us an idea of where to start debugging.
>
> I know this  is “suboptimal”  in terms of caching and multiple commits
> – but, we’re looking at “legacy code” that cannot be easily changed.
>
> Here’s simple test case that runs anywhere from 20% to 70% slower in
> similar (RHEL 7.3, X86) hardware. In fact, in one case, the 12c
> hardware had fewer cores (12 vs 32) and less ram (8G vs 32G) than the
> 19c environment.
>
> create table test_tab1 (
>
>    id number primary key,
>
>    c1 varchar2(1000)
>
> );
>
> create table test_tab2 (
>
>    id number,
>
>    t1_id number,
>
>    c2 varchar2(1000),
>
>    constraint test_tab2_fk foreign key (t1_id) references test_tab1
> (id) on delete cascade
>
> );
>
> create table test_tab1 (
>
>    id number primary key,
>
>    c1 varchar2(1000)
>
> );
>
> create table test_tab2 (
>
>    id number,
>
>    t1_id number,
>
>    c2 varchar2(1000),
>
>    constraint test_tab2_fk foreign key (t1_id) references test_tab1
> (id) on delete cascade
>
> );
>
> Then run 10000 of these transactions in a loop:
>
> insert into test_tab1 values (test_seq1.nextval,'hello');
>
> insert into test_tab2 values (test_seq2.nextval, test_seq1.currval,
> 'byebye');
>
> commit;
>
> Clay Jackson
>

-- 
Mladen Gogala
Database Consultant
Tel: (347) 321-1217


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