Tuning by understanding your application



This is a short post to illustrate how the understanding of how an application works can make all the difference to how you an tune it. This is a real world case which is actually pretty simple but i think illustrates the point quite well.

The performance symptoms were as follows:

1) Live environment works fine
2) Copy of that environment is very slow performing a specifc function - the data between the two systems (more...)

It’s From The Catalog


"Have you ever heard a blindfolded octopus unwrap a cellophane-covered bathtub?"
-- Norton Juster, The Phantom Tollbooth

Database upgrades aren’t terribly difficult in general, unless the upgrade is for an RMAN catalog database that has two catalogs with different versions. It’s completely ‘legal’ to have an 11.2.0.x RMAN catalog database with an additional 12.1.0.x catalog; this is where the going can get rough during an upgrade since the (more...)

Oracle Bundle Patches – release timing

I have to invest much of my time (at work) into Oracle and managing of patches, merge patches, patch requests and similar things.
At this task I identified an interesting (but probably worthless) information:
It seems a Bundle Patch (for Version 12.1) is defined approximately (at least) 40 days before it's released.
At least the 12.1.0.1.171017 BP follows this rule.

I have requested a lot of one-off and merge patches (more...)

Exadata Flash Cache enabled for Write Back

During Tests for an Migration of a major customer application we saw in our AWR reports that most of the jobs are very write intensive. This was the point where we would like to test what happens when we change the Flash Cache Mode from Write Through to Write Back.

What are the main benefits of Write Back mode:

  • it improves the write intensive operations while writing to flash cache is faster than writing to (more...)

Truncated CTAS statements seem to be no longer shortened

Many bloggers have already discussed that Oracle can truncate the text of a “create table as select” statement to 20 characters depending on your version and patch level. This can be a problem in case a CTAS statement is a resource hog, yet you don’t see the SQL text that is needed for troubleshooting. A quick search on My Oracle Support reveals this can happen on 11.2.0.4, 12.1.0.1 and (more...)

2017 SiOUG – Slovenia


Just as quickly as I had unpacked from #OOW17, it was time to think about the next 2 conferences. Slovenia and Croatia.

I spoke in Slovenia before in 2011. I was invited by Joze Senegacnik  who I knew from the Oak Table. I had had a wonderful time and we stayed in Portoroz on the coast. 

I didn't blog about that conference but I did comment on the three most wonderful user group presidents and (more...)

After the party is before the party

Now two months after the #pougtrip everything went back to normal. Except the planning for the next events.

The DOAG #NextGEN is currently starting a "roadshow" at German universities.

Start is the 07.11.2017 at the university of Trier. We will have 3 presentations covering different technologies: SQL, JS, JSON, SVG, PL/SQL, REST and APEX.
But see for yourself: Oracle Vorträge an der Hochschule Trier


As you can see the agenda is made with (more...)

Oracle Critical Patch Update October 2017 Oracle E-Business Suite Analysis and Impact

As with almost all previous Oracle E-Business Suite Critical Patch Updates (CPU), the October 2017 quarterly patch is significant and high-risk. 47 of the past 52 quarterly patches are significant and high-risk as they fix one or more SQL injection vulnerabilities or other damaging security vulnerabilities in the web application of Oracle E-Business Suite. Despite the publicity, marketing, or naming of specific vulnerabilities, this quarter is no different than previous quarters in terms of risk (more...)

Part V of my article series "Database as a Service using Enterprise Manager"


This is Part V of my article series "Database as a Service using Enterprise Manager" 


https://goo.gl/q92vYE


Best method for tuning sub-optimal execution plans

How do you determine if the Oracle SQL optimizer has created a sub-optimal execution plan? re-run statistics and see what happens? wait for Oracle to fin other execution plans? What if neither method is helping? Do you read the execution plan? What do you look at? Differences in actual vs estimated? How successful is that? Look for full table scans?  Do you look at the 10053 trace? How much time and effort does that take?  (more...)

Selective persistence of Oracle Diagnostic Logging (ODL) output

Background and Goal

In any application, logging is widely used for diagnostics and debugging. 

Logging at various "checkpoints" (such as entering with request, exiting with response, error handler) in the application can provide a fairly reliable way to trace the execution path of the application - which a subsequent sweep or count can be used to report on. When the logs are regularly analysed and reported on, anomalies can get flagged up proactively and (more...)

Your DBA Career in the Age of Oracle Cloud

Attend the free webinar by Oracle ACE Director Craig Shallahamer and learn how the Oracle Cloud and the Oracle 18c autonomous database changes your role as an Oracle DBA.
About the Webinar
The cloud is a change that all Oracle DBAs must face. The cloud is here stay, and that means Oracle DBAs need to adapt or get out of the game. It makes no difference if you are a new Oracle DBA or retiring (more...)

KSQL: Streaming SQL for Apache Kafka

KSQL: Streaming SQL for Apache Kafka

Few weeks back, while I was enjoying my holidays in the south of Italy, I started receiving notifications about an imminent announcement by Confluent. Reading the highlights almost (...I said almost) made me willing to go immediately back to work and check all the details about it.
The announcement regarded KSQL: a streaming SQL engine for Apache Kafka!


Oracle XE 12c becomes Oracle XE 18c

Oracle Database, Express Edition (XE) is a free version of the Oracle Database, currently available as version 11g (11.2) for Windows and Linux.
A planned new version of Oracle XE based on 12c (12.2) was first mentioned back in 2013. Now we are in 2017 and Oracle has changed its version numbering, aiming for yearly releases of the database, which means that after 12c comes 18c (in 2018) and 19c (in 2019) and (more...)

Gavin Soorma Implementation Workshop: GoldenGate 12c

From fellow Oracle Certified Master Gavin Soorma:

Register for the new Oracle GoldenGate 12c Release 3 online training course from Gavin and learn all about the exciting new features in Oracle 12.3 OGG like the Microservices Architecture, Parallel Replicats, Automatic Conflict Resolution and more as well as fast track yourself towards acquiring the skills to implement and maintain an Oracle 12c GoldenGate replication environment. Great for cloud database migrations as well.


Course Duration: 20+ (more...)

If you’re in Panama, Colombia, Ecuador, Paraguay, Brazil or Argentina, Oracle APEX is coming to you!


In the first part of November, my colleague David Peake and I are taking the Oracle APEX & Oracle Database Cloud message to a number of Oracle user groups and communities who are graciously hosting us as part of the Oracle Developer Tour Latinoamérica.  These are countries for which there is growing interest in Oracle Application Express, and we wish to help support these groups and aid in fostering their growing APEX communities.

The (more...)

Geographical clusters with the biggest concentration of web services

From a data set of approximately 145 million IP addresses running at least one publicly accessible web service (such as a website), I was able to determine these 20 geographic "clusters".



Note that these are not "20 locations with the most number of web services" but data set clustered into 20 geo locations - similar to centres of gravity. (Which is why some of the clusters appear in the sea). It is not surprising that (more...)

Enable SSL-encryption for MariaDB Galera Cluster

Imagine you have MariaDB Galera cluster with nodes running in different data centers. Data centers are not connected via secured VPN tunnel.
As database security is very important you must ensure that traffic between nodes is fully secured.

Galera Cluster supports encrypted connections between nodes using SSL protocol and in this post I want to show how to encrypt all cluster communication using SSL encryption.


Check current SSL configuration.

MariaDB [(none)]> SHOW VARIABLES LIKE 'have_ssl';
(more...)

Jeremy on the Role on Emerging Technology

Here’s a video from our Group Vice President, Jeremy Ashely (@jrwashley)  about Emerging Technology and how it should be helping people to use the system. This is a nice, concise description of what we do and why.

https://www.youtube.com/watch?v=1sLV2JGQpFgPossibly Related Posts:

Roll With It


"I know one thing for certain; it is much harder to tell whether you are lost than whether you were lost,
for, on many occasions, where you are going is exactly where you are. On the other hand, if you often find
that where you've been is not at all where you should have gone, and, since it's much more difficult to
find your way back from someplace you've never left, I suggest you go  (more...)