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June 2017

PLSQL test data from cursor to table or from cursor to csv

When you are creating test data it is usually either to create a quick test table for
a piece of code, or because you need to simulate data extraction to another system. That is why
any generator created with testdata_ninja includes methods to do that quickly. Every generator created
includes a to_table method and a to_csv table function.

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 good part of their lives on the M25 Smile  I used the M25 as a metaphor for how database professionals can focus on the wrong things when trying to solve a performance problem, such as:

“I’m stuck in traffic…perhaps a faster car will help”

ie, throwing CPU at a problem that is not CPU bound will not help things, or

“I’m stuck in traffic…it must be the width of the paint on the lane markings”

12c NSSn process for Data Guard SYNC transport

In a previous post https://blog.dbi-services.com/dataguard-wait-events-have-changed-in-12c/ I mentioned the new processes NSA for ASYNC transport and NSS for SYNC transport. I’m answering a bit late to a comment about the number of processes: yes there is one NSSn process per LOG_ARCHIVE_DEST_n destination in SYNC and the numbers match.

Here is my configuration with two physical standby:
DGMGRL> show configuration
 
Configuration - orcl
 
Protection Mode: MaxPerformance
Members:
orcla - Primary database
orclb - Physical standby database
orclc - Physical standby database
 
Fast-Start Failover: DISABLED
 
Configuration Status:
SUCCESS (status updated 56 seconds ago)

Ora-600

Zrozumieć wyrocznię

Unpivot

An interesting observation appeared recently as a side-channel on a question on the OTN database forum – how does Oracle execute an unpivot() operation. Here’s an example of such a query:

E4 Session Developing Agnostic Data Services

Thank you for all attending my virtual session Developing Location and Technology Agnostic Data Services at Accenture Enkitec's E4 2017 Conference.

Here is the presentation deck for your reference. http://www.proligence.com/pres/e4_2017/e4_17_data.pdf

As always, I will appreciate your feedback--the good, the bad and the ugly.

NYOUG Session How Oracle Buffer Cache Works

Thank you all for coming to my session How Oracle Buffer Cache Works at New York Oracle User Group Summer General Meeting in New York City.

You can download the session and scripts used for the demo here.

Presentation : http://www.proligence.com/pres/nyoug17/nyoug17_buffercache.pdf
Scripts : http://www.proligence.com/pres/nyoug17/nyoug17_buffercache_scripts.zip

As I mentioned during my talk, you may find these blogposts helpful to understand this more:

How Oracle Locking Works http://arup.blogspot.com/2011/01/how-oracle-locking-works.html

Where in the World is DBA Goth Girl- Week 24

I just returned from a week in Paris and it was fantastic!

12cR2 PDB refresh as a poor-man standby?

Disclaimer

My goal here is only to show that the Refreshable PDB feature works by shipping and applying redo, and then can synchronize a copy of the datafiles. I do not recommend to use it for disaster recovery in any production environment yet. Even if I’m using only supported features, those features were not designed for this usage, and are quite new and not stable yet. Disaster Recovery must use safe and proven technologies and this is why I’ll stick with Dbvisit standby for disaster recovery in Standard Edition.

This post explains what I had in my mind whith the following tweet:
CapturePoorManSBY

dbms_sqldiag

If you’re familiar with SQL Profiles and SQL Baselines you may also know about SQL Patches – a feature that allows you to construct hints that you can attach to SQL statements at run-time without changing the code. Oracle 12c Release 2 introduces a couple of important changes to this feature:

  • It’s now official – the feature had been copied from package dbms_sqldiag_internal to package dbms_sqldiag.
  • The limitation of 500 characters has been removed from the hint text – it’s now a CLOB column.

H/T to Nigel Bayliss for including this detail in his presentation to the UKOUG last week, and pointing out that it’s also available for Standard Edition.