More on Optimistic Locking with ORA_ROWSCN

Thanks to comments by Tony Hasler and pingbacks from Jeff Kemp, here's more detail on how optimistic locking works with SCNs, especially with respect to "restarts" during update.

DIY parallel task execution

We had a question on AskTOM recently, where a poster wanted to rebuild all of the indexes in his schema that had a status of UNUSABLE.  Running the rebuild’s in serial fashion (one after the other) seemed an inefficient use of the server horsepower, and rebuilding each index with a PARALLEL clause also was not particularly beneficial because the issue was more about the volume of indexes rather than the size of each index.

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Optimistic Locking: One SCN to rule them all

Previously I showed how to avoid lost updates with ORA_ROWSCN. Now let’s create an API that avoids lost updates with just one SCN. What kind of API? A transaction consists of one or more changes to data that should happen together: either all should happen or none. When the transaction commits, all the changes happen; […]

It’s just bad code or bad design … most of the time

Some years ago I wrote an article for the UKOUG magazine called “Want a faster database – Take a drive on the M25”.  For those not familiar with the United Kingdom, the M25 is one of its busiest roads (M = “motorway”) and because it moves so much traffic, and runs so close to capacity, it has often been referred to as “the world’s largest car park”.  Many people have probably spent a (more...)

Avoiding Lost Updates with ORA_ROWSCN

Applications today use "optimistic locking" to avoid lost updates. Tom Kyte thought of using ORA_ROWSCN for optimistic locking, then decided it didn't work (see ORA_ROWSCN for optimistic locking). I now think it does!

Modified PythonDBAGraphs to use datetime on X axis

I modified PythonDBAGraphs to use datetime objects on the X axis for all the reports except ashcpu.py. This lets you hover the mouse over a point and see the date and time for the point. Previously I was using text strings as labels with dates and times on the X axis and it was not obvious which point was for which date and time.

Here is a screenshot:

I have an example of a (more...)

I Am Speaking at OTN Yathra 2017

RSS content

The Oracle ACE directors and Oracle Volunteers  in the region are organizing their third evangelist event called ‘OTNYathra 2017’ during the month of June 2017 in a time period of 3 weeks. This yathra, managed by ACE directors and Oracle Volunteers of the region, is to travel across the country covering over six major IT focused cities (Chennai, Bangalore, Hyderabad,  Pune, Mumbai and Gurgaon) . It aims  to bring the Oracle community together, giving them awareness (more...)

EBS 12.1.3 Data masking issue with 11.2.0.2

I tried to data mask the EBS 12.1.3 data with database version 11.2.0.2. but After i masked, I can’t open the application because of SYSADMIN and Guest user was missed. So I raised SR, As per support we need to upgrade database version to 11.2.0.3 otherwise we need to do backport activity. If your database version is 11.2.0.2, you need to check with Oracle (more...)

Pushed out new version of PythonDBAGraphs

I pushed out a new version of PythonDBAGraphs. I got a new laptop at work so I am setting it up with the software that I need to do my job. I decided that instead of reinstalling Enthought Canopy I would go with the current version of Python 3 and install the packages that I need one at a time. This gives me a cleaner install and I’m on the most current version of Python (more...)

Index compression–quick tip

If you’re appropriately licensed and want to use advanced index compression, you can take advantage of the “db_index_compression_inheritance” parameter which will let you establish compression as a default at a nominated level in the database.  From the docs:

Values:

TABLESPACE

Indexes will be created with ADVANCED LOW compression if the tablespace they reside in has OLTP compression enabled as the default.

TABLE

If the underlying table is OLTP compressed, the indexes on this table (more...)

OTN Yathra 2017

The amazing 6 city set of events is just around the corner, with all of the dates and details available at http://otnyathra.in/

image

Here are my thoughts on why you should be attending


Instrumentation … not just for debugging

Yeah I know.  You’re probably thinking “Here’s another blog post from someone telling us how important it is to instrument our code, so we can get better debugging, better performance, blah blah blah”.

If that is your sentiment, then I’m thrilled because it means the instrumentation message has got through to the extent that it is now considered just a statement of the obvious.  As many will know, my predecessor was a huge (more...)

X86-64 Assembly Book

I have written earlier blog posts about my diversion from studying Oracle to studying computer science. Here are some relevant posts: url1,url2,url3,url4. After finishing the math for computer science online class and book that I was working on I stared working through a book about assembly language programming. I bought the book in a frenzy of enthusiasm about studying computer science for fun. But then I had to decide (more...)

Docker, Oracle Images and Cloud

Overview

Oracle is embracing Docker – just like many other companies – as the de-facto standard in Container technologies. It has resulted in the certification of various Oracle products for running in Docker containers and even Oracle supported Docker images are available. Furthermore, Oracle offers 2 Cloud Service around containers: the Container Cloud Service is a generic service that offers a platform for running your containers. Next to that, Oracle offers the Application Container Cloud (more...)

The village idiot

If you are not familiar with the term Village Idiot, then Wikipedia provides a sufficient definition from which I can base this blog post.

https://en.wikipedia.org/wiki/Village_idiot

“The village idiot … is a person known for ignorance or stupidity”

Over the past couple of weeks I’ve been flying a bit.  First was OpenWorld and OracleCode in New Delhi in India, and from there, I was heading straight from there to Cleveland, Ohio for the (more...)

Finished reading the Snowflake database documentation

I just finished reading the Snowflake database documentation and I thought I would blog about my impressions. I have not spent a lot of time using Snowflake so I can not draw from experience with the product. But, I read all the online documentation so I think I can summarize some of the major themes that I noticed. Also, I have read a lot of Oracle database documentation in the past so I can compare (more...)

SQL FUNDAS

NA

The post SQL FUNDAS appeared first on DBACLASS.

Did You Know #19 – Using LIKE

The LIKE operator is a very useful one. It is used to match strings with partial match while using the underscore (‘_’) as a single character wildcard and the percentage sign (‘%’) as multiple character wildcard. There are a few things you should know and some tricks you can use with the LIKE operator: The underscore … Continue reading Did You Know #19 – Using LIKE

Cedar’s Oracle Talent Acquisition Cloud Event / Team

Earlier this week Cedar held its Oracle Talent Acquisition Cloud event in Oracle’s London City office. We have a really strong team of UK-based Talent Acquisition specialists within our ranks:

Taleo Team 2 (plain background)

Jo, Prachi, Marc and Mel are all experts in the various aspects of Oracle Talent Aquisition Cloud – Taleo Recruit, Sourcing and Onboarding – and Cedar has multiple implementations under our belt covering all of the above products, so we were able to put on (more...)

Comparing Expression Lists (not tuples)

This post is a long-winded answer to a question Bryn Llewellyn asked me on Twitter about comparing expression lists.