Oracle Database as our consultants live it every day: installation and patching, upgrades, RMAN backup and recovery, Data Guard, RAC, performance tuning, multitenant, licensing, and engineered systems such as ODA and Exadata.
By Franck Pachot . You are a speaker and like to show some demos. Which kind of demo do you do? you script everything so that you just have to press ‘enter’ during the demo you prepare everything in a text file and copy/paste during the demo you type everything in live? I don’t like the first one because it’s…
By Franck Pachot . Rumors are coming after OOW14. Oracle is working on a new SQL*Plus version. Not only a new version. It’s a completely new development. Here is what we know currently about the future of sqlplus an sqldeveloper. But I start with some very old stuff. SQL*Plus sqlplus is an old tool. With many features that look as…
By Franck Pachot . A frequent scenario: you refresh test from production with a RMAN duplicate. Once the duplicate is done, you probably change dblinks so that they address the test environment instead of the production one. But are you sure that nobody will connect in between and risk to access production from the test environement? You want to disable…
By Franck Pachot . A question that I had several times: in Enterprise Manager, in the screen about one SQL statement, the ‘statistics’ tab shows the number of executions, elapsed time, etc. Question is: which time window does it cover? There is a one hour chart above, and two timestamps displayed as ‘First Load Time’ and ‘Last load Time’, and…
By Franck Pachot . Here is an odd Oracle behavior I observed when a transaction that acquired a lock is rolled back. Note that this is related to a specific combination of locks that should not be encountered in production. So it’s not a bug. Just something unexpected. First session In my first session I lock the DEPT table…
By Franck Pachot . Do you know why Oracle Database is a leader in the database market since 30 years? Do you know any other software that is still the leading solution after decades? I think that it is because Oracle has been a good software from the get-go. Many early decisions in the software architecture have revealed themselves later…
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. Fragmented index I have an index created when the table had 1 million rows. Then, I deleted 90% of the rows. Here…
By Franck Pachot . When can we use IOT? That’s a question I had when giving recently the Oracle DBA essentials workshop. the DBA Essential is very dense and there is only half a day about performance. We have the Oracle Performance Tuning workshop to go into those details. But IOTs are under used in my opinion, so I’ll post…
By Franck Pachot . System statistics can be gathered in NOWORKLOAD or WORKLOAD mode. Different values will be set depending on that and the others will be calculated – derived from them. We can see defined values from SYS.AUX_STATS$ but here is a script that shows the calculated ones as well. With no system statistics or NOWORKLOAD the values of…
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 always well understood: how index space is managed, block splits, fragmentation, coalesce and rebuilds. Kyle Hailey has made a video of it available…
By Franck Pachot . A thread on OTN Forum about Exadata came to the following question: “But how can I monitor if it is effectively used or not?”. This is a common question. There are 3 exclusive features coming with Exadata, and instance statistics can show their usage. Even better: two of them can even be checked on your current (non-Exadata)…
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 a few ideas. Why? Why do you want to downgrade to the Standard Edition? For licensing costs, of course. Today, it…
