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August 2013

The Fall of Hyperion

The Fall of Hyperion is the second book in the Hyperion Cantos series by Dan Simmons.

I’m not really sure what to say about The Fall of Hyperion. On the one hand, I was very interested to see what happened to the characters from the previous book. On the other hand, this book was much less focussed and quite disjointed at times. It didn’t help that it took me a long time to get through it, reading it in small snippets, rather than a few long sittings.

Despite my minor misgivings, I’ve already started the next book in the series and I’m keen to see how this plays out.

Cheers

Tim…

PS. I’ve just checked the dates between this post and the one from the proceeding book. It took about 2 months to get through it. I’m sure that has a big factor on my perception of it.

Bloom Filter

I’ve posted this note as a quick way of passing on an example prompted by a twitter conversation with Timur and Maria about Bloom filters:

The Bloom filter (capital B because it’s named after a person) is not supposed to appear in Oracle plans unless the query is executing in parallel but here’s an example which seems to use a serial Bloom filter.  Running in 11.2.0.3 and 12.1.0.1 (the results shown are the latter – the numbers are slightly different between versions):

Interview with Jonathan Lewis

If you follow my Twitter you probably have heard that Jonathan Lewis visited Moscow in May this year. Thanks to Innova, Jonathan gave a 1-day seminar, and I was one of the lucky people from Russian Oracle community who have been invited to the event.
Even more, I was offered to take an interview with Jonathan which was recorded! It was my first time interview and I was very excited (long before the recording) and scared to death (right in front of the camera) so please forgive me for speaking like a dull. I know that, and it almost doesn’t matter. What matters is Jonathan was brilliant and so excited at times, that 90+ minutes of sitting in a cold room right under air conditioner for me flew like a 1 minute.
Well, enough the words, just enjoy it (this is uncut version recorded in 1 go by the way)!

Fast refresh of aggregate-only materialized views – introduction

This post introduces a series about the algorithm used by Oracle (in 11.2.0.3) to fast refresh a materialized view (MV) containing only an aggregate:

create materialized view test_mv
build immediate
refresh fast on demand
with rowid
as
select gby        as mv_gby,
       count(*)   as mv_cnt_star,
       AGG  (dat) as mv_AGG_dat,
       count(dat) as mv_cnt_dat
  from test_master
 where whe = 0
 group by gby
;

Where AGG is either SUM or MAX, the most important aggregates.

In the next posts, I will illustrate the algorithms used to propagate conventional (not direct-load) inserts, updates and deletes on the master table; I will illustrate also the specialized versions of the algorithms used when only one type of DML has been performed (if they exist).

12c Histogram fixes

I posted a couple of examples some time ago of oddities and boundary cases for frequency histograms on character columns. Part of the process of playing around with the 12c Beta was to re-run such cases to see if newer code made any difference. Looking at these examples, one was fixed (or improved, at least) the other wasn’t, so I’ve added a footnote to each and produced this little note to highlight the changes:

LAOTN Tour (Southern Leg) : PEOUG…

Jonathan Lewis‘ sessions (over WebEx) about “Designing Optimal SQL” and “How to Hint” were extremely popular. The room was full and the audio and slides were very clear. I would say approximately 3/4 of the audience were wearing the simultaneous-translation earphones. Everyone looked very focussed! It was a pity Jonathan couldn’t make it in person, but this was a much better alternative than cancelling his sessions!

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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