Why the In-Memory Column Store is not used (II)

Now after some research - I detected one simple rule for provoking In-Memory scans :

Oracle In-Memory Column Store Internals – Part 1 – Which SIMD extensions are getting used?

This is the first entry in a series of random articles about some useful internals-to-know of the awesome Oracle Database In-Memory column store. I intend to write about Oracle’s IM stuff that’s not already covered somewhere else and also about some general CPU topics (that are well covered elsewhere, but not always so well known in the Oracle DBA/developer world).

Before going into further details, you might want to review the Part 0 of this series and also our (more...)

Is it unique?

Major take-aways from Oracle OpenWorld 2014 – some relevant conclusions

image

Oracle OpenWorld 2014 is over. Just under a week, full to the brim with information, events, people, energy, plans, hopes and expectations. I have learned many, many things. Small things, important facts, huge insights and many great people. In this article, I will attempt to sum up the largest themes of the conference as I have interpreted them. In subsequent publications, I will focus on some of them as well as discuss less grand but (more...)

Extending an ACFS filesystem dynamically.

To extend an ACFS cluster filesystem dynamically, we need to use the acfsutil command:

node01:/u01/grid>/sbin/acfsutil size +10G /u02
acfsutil size: ACFS-03008: The volume could not be resized.  The volume expansion limit has been reached.
acfsutil size: ACFS-03216: The ADVM compatibility attribute for the diskgroup was below the required
                           version (11.2.0.4.0) for unlimited volume expansions.

Oh dear, not 11.0.2.4, so you can only extend volumes dynamically a (more...)

Abstract Review Tips

Yes, this is for my RMOUG abstract reviewers, but it may help other conferences and user groups, too.  We have some incredible content at RMOUG, (Rocky Mtn. Oracle User Group) Training Days conference and its all due to a very highly controlled, thought out process that has evolved over time to ensure that we have an abstract selection process that is as fair as possible and offers new speakers opportunities as well.

I’m going to (more...)

RAC, 12c and Direct Path Reads

Yes, direct path reads again :) No worries I’m already a bit bored from digging in this algorithm, so I think this is going to be my last post about it. Till they change it again of course. And yes, in 12.1.0.2 they did. For introduction to DPR, you can check my previous post, because […]

OOW14 Session: The Art and Craft of Tracing

A big thanks to all those who braved attending my session on the final day of Oracle Open World 2014. I hope you enjoyed it and found it valuable.

You can download the slide deck as well as the scripts I mentioned here.

As always, I would love to hear from you.

Advanced Queue Quickie: Errors and Privileges

File this one under the misleading-errors department. One of my developers was working with a new queue. He pinged me when he got this error trying to create a job that used the queue:

ERROR at line 1:
ORA-27373: unknown or illegal event source queue
ORA-06512: at "SYS.DBMS_ISCHED", line 124
ORA-06512: at "SYS.DBMS_SCHEDULER", line 314
ORA-06512: at line 2

The CREATE_JOB statement was:

BEGIN
DBMS_SCHEDULER.CREATE_JOB(
job_name => 'foo.bar_q_job',
job_type => 'PLSQL_BLOCK',
(more...)

Oracle OpenWorld 2014 – An OakTable World picture presentation

Shrink Tablespace

In a comment on my previous post on shrinking tablespaces Jason Bucata and Karsten Spang both reported problems with small objects that didn’t move to the start of the tablespace. This behaviour is inevitable with dictionary managed tablespaces (regardless of the size of the object), but I don’t think it’s likely to happen with locally managed tablespaces if they’ve been defined with uniform extent sizes. Jason’s comment made me realise, though, that I’d overlooked a feature of (more...)

I’m speaking at…

HROUG,SIOUG and BGOUG. At HROUG and SIOUG I’ll be speaking for Exadata and at BGOUG, maybe for near zero downtime migration or some similar geeky topic ;) Links to the events:         Have fun! Kovachev

Oracle #GoldenGate Parameter File Templates

This week I’ve been enjoying spending some time at Oracle Open World in San Francisco, CA.  While here, I’ve been talking with everyone, friends old and new, and it came to my attention that it would be a good idea to have some useful templates for Oracle GoldenGate parameter files.  With this in mind, I decided to create some generic templates with comments for Oracle GoldenGate processes.  These templates can be found on my Scripts (more...)

The Best Question So Far

So I was in a session here at OOW14 on “User Group Sunday” when one of the attendees asked what I consider to be the best question I’ve heard in a long, long time.

If the Oracle Cloud is so wonderful, why haven’t all of Oracle customers moved to it already?

Great, great question.   Goes straight to the heart of one of Oracle’s primary messages.  The answer played out as something close to (more...)

12c Fixed Subquery

It’s been about 8 months since I posted a little note about a “notable change in behaviour” of the optimizer when dealing with subqueries in the where clause that could be used to return a constant, e.g.:


select
	*
from	t1
where	id between (select 10001 from dual)
	   and     (select 90000 from dual)
;

There’s been a note at the start of the script ever since saying: Check if this is also true (more...)

Releasing to schemas the easy way

Sometimes we occasionally just miss the obvious, for years. Just noticed that an easy way to release code to a particular schema is to login as your normal DBA user (USER1) [as preferred by audit], use the alter session command to switch to point to the release schema (USER2) and run your DDL. Oracle behaves, from an object-owner perspective, as if you are logged-in as the schema owner without all the negative aspects of actually (more...)

OOW14 Session: Cache Buffer Chains Latches Demystified

Thank you all those who came to attend my session "Demystifying Cache Buffer Chains Latches" at Oracle Open World 2014. Much appreciated. I hope you got something out your time investment.

I have also written a paper to accompany this session. The paper explains the concepts I presented in greater detail. You can download a zip file containing the slide deck, the paper and the scripts here. Please note: this is a zip file.

And, (more...)

Oracle Cloud – Keeping Your Perspective

The fact that we live at the bottom of a deep gravity well, on the surface of a gas covered planet going around a nuclear fireball 90 million miles away and think this to be normal is obviously some indication of how skewed our perspective tends to be.”
             - Douglas Adams, The Salamander of Doubt: Hitchhiking The Galaxy One Last Time

Oracle OpenWorld kicks off tomorrow.  My (more...)

Exciting things happening in Coherence…

I hope everyone is attending/watching JavaOne 2014 tomorrow.   There’s a sneak preview of some cool next generation Coherence with Java 8 in the Java One Technical Keynote

Follow @JavaOneConf and @pinocchiocode to find out more…


The Hitchhiker’s Guide to the EXPLAIN PLAN: The story so far (Part 11–23)

On the Toad World site, I’m writing a series of blog posts and Wiki articles on the subject of EXPLAIN PLAN. I’m using EXPLAIN PLAN as a motif to teach not just SQL tuning but also relational theory, logical database design, and physical database design. In a year’s time, I hope to have enough material for […]