The Importance of the In-Memory DUPLICATE Clause for a RAC System

With the INMEMORY clause you can specify 4 sub-clauses:

  • The MEMCOMPRESS clause specifies whether and how compression is used
  • The PRIORITY clause specifies the priority (“order”) in which the segments are loaded when the IMCS is populated
  • The DISTRIBUTE clause specifies how data is distributed across RAC instances
  • The DUPLICATE clause specifies whether and how data is duplicated across RAC instances

The aim of this post is not to describe these attribues in detail. Instead, (more...)

Concurrent statistics gathering in 12.1.0.2

Prompted by an actual task at hand I spent some time investigating an 11.2.0.2 feature – concurrent statistics gathering. It has been on my to-do list for quite some time but so far I didn’t have a use case, and use cases make it so much easier. The question was-how can I gather statistics on a really large, partitioned table? Previously, you could revert to the degree in dbms_stats.gather_table_stats to ensure that (more...)

Cache Buffer Chains Demystified

You must have seen sessions waiting on the event “latch: cache buffers chains” from time to time. If you ever wondered what this means and how you can reduce time spent on it, read on. Here you will learn how buffer cache works, how Oracle multi-versioning works, how buffers are allocated and deallocated, what hash chain is and how buffers are linked to it, what the role of cache buffer chain latch is and why (more...)

ECO 2014 and Slides

Last week I attended the East Coast Oracle User Group conference, also known as ECO, in Raleigh, NC.  This being my first time at ECO, it was a good event for being a two day conference.  The low-key environment provided a nice, comfortable environment for interaction between the speakers and those in attendance.  If you ever have the chance to catch this conference, it would be a good one to attend.

What you can expect (more...)

Is Continuous Integration compatible with database applications ?

Continuous integration offers huge efficiency gains for companies  but is continuous integration even possible when the application’s backbone is a massive relational database. How can one spin up database copies for developers, QA, integration testing,  and delivery testing ?  Its not like Chef or Puppet can spin up a 10TB database copy in a few minutes the way one can spin up a Linux VM.

There is a way and that way is called data virtualization (more...)

Next Club Oracle London – 12th November 2014

The next Club Oracle London is taking this place, on Wednesday 12th November. You can find the details here.

This is a free evening or Oracle talks provided by some of our local experts and beer/snacks provided by e-DBA. The first event was back on the 3rd of July and it was a great evening. The coming event will have presentations by James Anthony, Dominic Giles and Jason Arneil in 12C in-memory database, key facts (more...)

SQL Developer and Big Data Appliance (sort of)

Recently, Enkitec received an Oracle Big Data Appliance (BDA) for our server farm in Dallas (Thanks Accenture!).  With this new addition to the server farm, I’m excited to see what the BDA can do and how to use it.  Since I use Oracle SQL Developer for a lot of things, I figure I better see if I can connect to it…. wait I don’t have access yet, darn!  Simple solution, I’ll just use the (more...)

rmoug 2015 presentation ready to go … makes me ( not ) grumpy

All ready to roll with RMOUG 2015 Training days presentation "OS Truth, little white lies, and the Oracle Wait Interface".

Best of course to come to RMOUG 2015 Training days ... but this is link to pdf version of the presentation here: John Hurley RMOUG 2015

If you are out there ( very excited personally my first time at this conference ) please kick me and say hello.  Ok maybe skip the kicking part ...


handy ash queries to look at blocked sessions ( how many when for what event ) …

Licensing may be required ... please check if applicable.

A query like this can be used to check how much blocking and what session it was ... ( so then you can drill into those blockers sessions ).  Probably can be done easily with some kind of rollup query?

Adjust SAMPLE_TIMEs in where clause below.

select ash_data.*, substr(sqlinfo.sql_text,1,70)
from
(SELECT to_char(ash.sample_time,'MM/DD/YYYY HH24:MI:SS') what_time,  count(*) sessions_blocked, ash.event, ash.blocking_session, ash.blocking_session_serial#, ash.sql_id, (more...)

Elevated Task Manager Shortcut on Windows 7

Received a replacement laptop so now I have to perform some software installs and configure it the way I had my old laptop.  To get Task Manager to display All Processes without having to select that option every time, it needs to run as Administrator.  Searched Google and found this link which describes how to […]

Singapore Oracle Sessions – Beginnings

Last Monday evening we had the first Singapore Oracle Sessions - an informal meetup of Oracle professionals thrown together at the last minute by a few of us.

Morten Egan (or as I believe he is called in Denmark now - The Traitor ;-)) mentioned to me months ago that if there was no user group when we arrived in Singapore, then we should start one. At the time he was the current (now retired) (more...)

Securing Oracle GoldenGate Database Login in a Credential Store

Security is always a big deal.  In setting up Oracle GoldenGate the capture (extract) and apply (replicat) parameter files need to be configured to log in to the database which they will perform operations.  In order to do this the Oracle GoldenGate User name and password need to be provided in the parameter files.  Example 1 shows how the database login is traditionally done in a extract or replicat parameter file.

Example 1:

--Oracle Login
 (more...)

Quiz night

Prompted by an email from Yves Colin (who’ll be presenting on the Tuesday of UKOUG Tech14) I was prompted to dig out a little script I wrote some years ago and re-run an old test, leading to this simple question:  what’s the largest size array insert that Oracle will handle ?

If you’re tempted to answer, watch out – it’s not exactly a trick question, but there is a bit of a catch.

 


setting pctfree to 0 for regular indexes … ( not familiar with this theory ) … help!?

One of my coworkers has this theory ( habit ) of creating new regular indexes on regular table columns.  Not compressed indexes or anything special.

He is currently believing ( back from somewhere / not sure of the origin ) that "if a table only gets inserts and deletes" that any indexes created on that table should be set with pctfree set to 0.

I do not agree.  In my opinion one should (more...)

Using APEX to Create a Mobile User Interface for Enterprise Manager 12c

On November 11th, I will be presenting at Oracle Day Istanbul. My presentation will be about creating a mobile interface (a simple application) using Application Express to access Oracle Enterprise Manager repository views (and some procedures) to manage incidents and problems. I know that there’s already an application for idevices, but my application is a web application designed for mobile (thanks to APEX), so it’s compatible with all devices. The sessions are short, only 30 (more...)

Friday Philosophy – Is Dave Productive?

How do I know if Dave is doing his job properly? If I am his (or her*) manager, what techniques can I use to ensure I am getting my pound of flesh out of this worker drone in return for the exorbitant salary my company puts into said drone’s bank account each month?

Well, as a start there is my last Friday Philosophy all about analysis of work profile via auditory analysis of input devices (more...)

AUSOUG conference Perth

The annual two day AUSOUG conference in Perth is well underway, and so far, its been a wonderfully successful event. In particular, we Australians are notorious for not really getting into the networking thing, so conferences often have a lot of ‘awkward silences’ when sessions are not on, and we are meant to be (god forbid) *talking* to each other :-)

But this year has been different. Lots of banter, lots of discussion. Also, the (more...)

A Summer at CERN: Evaluating OpenStack Trove as DBaaS Solution

I have been one of the 23 students participating in the CERN openlab summer student programme this year. Like two of my fellow students in the database group, Sneha and Anti already did, I want to share some insights into the project I worked on and in general about my experience with the summer programme. Thus, the post is divided into a general part and a technical part, which will sum up what I (more...)

About Oracle’s Code of Ethics, MOS Confidentiality Clause, and Content Stolen from My Website

I strive to keep the number non-technical posts on this blog to the minimum. However, there are days when a non-technical post has to be written. This is one of such days.

Oracle Corporation, concerned about legal and ethical issues, not only provides to its employees a document entitled Code of Ethics and Business Conduct, but also expects that every employee adheres with the standards that the document sets. For the purpose of (more...)

A simple 12c query with a cool result …

Its not immediately obvious the significance of this query…but trust me…you’ll love it :-)

SQL> select table_name, column_name from dba_tab_cols
  2  where column_name like '%_VC' escape ''
  3  and owner = 'SYS'
  4  order by 1,2;

TABLE_NAME                     COLUMN_NAME
------------------------------ ----------------------
ALL_CONSTRAINTS                SEARCH_CONDITION_VC
ALL_VIEWS                      TEXT_VC
CDB_CONSTRAINTS                SEARCH_CONDITION_VC
CDB_VIEWS                      TEXT_VC
DBA_CONSTRAINTS                SEARCH_CONDITION_VC
DBA_VIEWS                      TEXT_VC
INT$DBA_CONSTRAINTS            SEARCH_CONDITION_VC
INT$DBA_VIEWS                  TEXT_VC
INT$INT$DBA_CONSTRAINTS        SEARCH_CONDITION_VC
USER_CONSTRAINTS               SEARCH_CONDITION_VC
USER_VIEWS                     TEXT_VC