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August 2013

LAOTN Tour (Southern Leg) : Arrived in Lima, Peru…

Yesterday did not start so well. My sleep was rather erratic, so I woke up in a bad mood. The taxi ride to the airport in Chile took a long time because of the traffic, but I had allowed plenty of time, so I still got to the airport with 2 hours to spare. For some reason I was not able to use the check-in machines, so I had to wait in a very long, very slow moving queue. That in itself was annoying, but more annoying was there seemed to be lots of staff at the counters just chatting, rather than dealing with the people in the queue. Airports are annoying at the best of times, but this sort of thing makes my blood boil.

LAOTN Tour (Southern Leg) : CLOUG…

As you will have gathered by now, the first event of the southern leg of the LAOTN Tour was Chilean Oracle User Group (CLOUG) in Santiago, Chile.

After the initial keynote, the main room became the Michelle Malcher and Tim Hall roadshow. We both picked up extra sessions to fill the gaps left by Jonathan Lewis‘ absence, so we were like a tag team, alternating throughout the day. :)  As a result, the conference seemed to go really quickly for me.

12c Asynchronous Global Index Maintenance Part I (Where Are We Now ?)

I previously looked at how global index maintenance was performed when dropping a table partition prior to Oracle Database 12c. Let’s see how things have now changed since the introduction of 12c. Let’s start by creating the same partitioned table and global indexes as previously: If we look at the current state of affairs, all […]

WordPress 3.6 Released…

WordPress 3.6 has arrived. You can read about it here.

I did the upgrade using the auto-update feature and it worked fine, as always.

Happy upgrading.

Cheers

Tim…


WordPress 3.6 Released… was first posted on August 2, 2013 at 4:31 am.
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Oracle Enqueue Rules Leading to Deadlock Changes Again in 12.1?

August 1, 2013 Four years ago while co-writing two chapters for an Oracle Database book, an interesting test case was put together to demonstrate how enqueues are handled when multiple sessions are competing for some of the same database resources – the test case was intended to demonstrate the neat, orderly, and predictable process implemented by Oracle Database.  Oracle Database 10.2.0.1 […]

Oracle Enqueue Rules Leading to Deadlock Changes Again in 12.1?

August 1, 2013 Four years ago while co-writing two chapters for an Oracle Database book, an interesting test case was put together to demonstrate how enqueues are handled when multiple sessions are competing for some of the same database resources – the test case was intended to demonstrate the neat, orderly, and predictable process implemented by Oracle Database.  Oracle Database 10.2.0.1 […]

OIC(A) again – 2

Continuing from the previous post, here is one more case when adjusting optimizer_index_cost_adj may hurt you.


Setup:

drop table t1 cascade constraints purge;
create table t1 (id, x, pad, constraint t1_pk primary key(id, x))
as
select trunc(rownum/10)
     , mod(rownum, 10)
     , s1.text
  from all_source s1, all_source s2
 where rownum <= 1e6;

exec dbms_stats.gather_table_stats(user, 't1', method_opt=>'for all columns size 1', cascade=>true, no_invalidate=>false)

alter session set optimizer_index_cost_adj = 100;
alter session set optimizer_index_caching  = 0;

explain plan for select * from t1 where x = :1;
@xp

Here’s the plan: