Oracle 12c

What about ALTER INDEX … SHRINK SPACE ?

By Franck Pachot . I have recently published a script to check index fragmentation. But then, do you COALESCE or REBUILD? Well, there also is another option: ALTER INDEX SHRINK SPACE. Let’s compare all those index defragmentation operations.

How to measure Oracle index fragmentation

By Franck Pachot . At Oracle Open World 2014, or rather the Oaktable World, Chris Antognini has presented ‘Indexes: Structure, Splits and Free Space Management Internals’. It’s not something new, but it’s still something that is not(…)

Thinking about downgrading from Oracle Enterprise to Standard Edition?

By Franck Pachot . You are using an Oracle Enterprise Edition and thinking about downgrading to the Standard Edition? In this case, you must be sure that your applications are compatible. It’s not something easy to check. Here are(…)

Oracle OEM Cloud Control 12.1.0.4 – AWR Warehouse

This post explains how to configure and use the new AWR warehouse functionality present in Enterprise Manager Cloud Control 12.1.0.4. This new feature offers the possibility to store date from the AWR of your main databases in the EM AWR(…)

Oracle 12.1.0.2.1 Set to Join Conversion

By Franck Pachot . Recently, I described the Partial Join Evaluation transformation that appeared last year in Oracle 12c. I did it as an introduction for another transformation that appeared long time ago in 10.1.0.3 but was not(…)

Oracle 12.1.0.2: Wait event histograms in μs

By Franck Pachot . When an Oracle Database spends a high percentage of its DB time in User I/O, I usually check the wait event histograms in order to see if the storage system is working well. But today,(…)

PostgreSQL for Oracle DBAs – an introduction

Having worked for several years as an Oracle DBA, I decided to have a look at the PostgreSQL database and see how it functions in comparison to the Oracle Database. The “Enterprise DB” graphical installation of PostgreSQL 9.3 is(…)

SQL monitoring 12.1.0.2 shows adaptive plans

By Franck Pachot . In a previous post, I have described Adaptive Plans. Even if I prefer to show plans with the SQL Monitor active html format, I had to stick with the dbms_xplan for that because SQL(…)

Beyond In-Memory, what’s new in 12.1.0.2 ?

By Franck Pachot . It’s just a patchset. The delivery that is there to stabilize a release with all the bug fixes. But it comes with a lot of new features as well. And not only the one that(…)

Partial Join Evaluation in Oracle 12c

By Franck Pachot . Do you think that it’s better to write semi-join SQL statements with IN(), EXISTS(), or to do a JOIN? Usually, the optimizer will evaluate the cost and do the transformation for you. And in this(…)