May 2014

Registration has opened for the Oracle Midlands Event #4 on Monday July 14th.

This event includes a session on “Designing Efficient SQL” by Jonathan Lewis as well as lightning talks by Jonathan Lewis, Richard Harrison, Salih Oztop, Patrick Hurley and Martin Widlake.

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I love this video on “getting dreadful database performance” by Stephane Faroult.
The video is hilarious and informative:

http://www.roughsea.com/vids/SQL_Best_Practices.html

Finally it’s official! I have started in a new role at Oracle, combining many years of work in both the database and Enterprise Manager arenas to being a database architect in the Database as a Service group in Enterprise Manager Product Management. My new role involves being the social presence for the group, both virtually […]

Does Oracle ignore hints – not if you use them correctly, and sometimes it doesn’t ignore them even when you use them incorrectly!

Here’s an example that I’ve run on 11.2.0.4 and 12.1.0.1

create table t1
as
with generator as (
	select	--+ materialize
		rownum id
	from dual
	connect by
		level <= 1e4
)
select
	rownum			id,
	rownum			n1,
	rpad('x',100)		padding
from
	generator	v1
;

begin
	dbms_stats.gather_table_stats(
		ownname		 => user,
		tabname		 =>'T1',
		method_opt	 => 'for all columns size 1'
	);
end;
/

create index t1_i1 on t1(id);
alter index t1_i1 unusable;

select n1 from t1 where id = 15;
select /*+ index(t1 (id)) */ n1 from t1 where id = 15;

Any guesses about the output from the last 4 statements ?