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May 2017

10 Things I Love About Tech- Python Edition

So since I already complained about what I hate about tech from a diversity and culture perspective, I felt I needed to explain all the things I love about tech and why I wouldn’t want to be anywhere else.

Everyone would expect me to start with databases or virtualization, but I thought I’d keep everyone on their toes and start with my favorite programming language- PYTHON!

AWS Database Blog – Added To My Blog Roll

This is just a brief blog post to share that I’ve added the AWS Database Blog to my blogroll.  I recommend you do the same! Let’s follow what’s going on over there.

Some of my favorite categories under the AWS Database Blog are:

 

 

Readers: I do intend to eventually get proper credentials to make some posts on that blog. All in proper time and with proper training and clearance.

12c nologging and Data Guard

The title sounds weird because Data Guard synchronisation is based on the redo stream, so it makes no sense to do nologging operations on the primary. And this is the reason why we set FORCE LOGGING on a Data Guard configuration. However, to lower the downtime of a migration done with Data Pump, you may want to import with minimal logging and then re-synchronize the standby. This post is about the re-synchronisation in 12.1

Nologging Data Pump

When you want to lower the downtime for a migration, you can disable force logging (alter database no force logging), and run impdp with the following: transform=disable_archive_logging:y
Don’t forget to re-enable force_logging at the end and to re-synchronize the standby.

Ten Things I Really Hate About Tech Today

I love working in tech.  I can honestly say that nothing gives me greater satisfaction than working on a technical challenge or having a brilliant conversation about technology with peers.  Other days I feel like a broken record having the same conversations with the women in technology around me, facing a lack of diversity and the consistent exclusion in tech.

Aliases

Here’s a performance problem that came up on OTN recently. The following query (reformatted) takes “ages” to run – how do you address the problem:

SELECT
	COUNT(*) 
FROM
	smp_dbuser2.workflow_step_report
WHERE
	report_ID IN (
		SELECT	report_id
		FROM	smp_dbuser2.workflow_report
		WHERE	trunc(start_time) = '28-Apr-2017'
		AND	user_id = 'nbi_ssc'
	)
;


Various pieces of relevant information were supplied (the workflow_report table holds 1.4M rows the workflow_step_report table holds 740M rows and some indexes were described), but most significantly we were given the execution plan:

Quick tip–identity columns

Lets say I’ve been reading about schema separation, and thus I am going to have a schema which owns all of my objects, which I’ll call APP_OWNER, which will have no connection privilege and a separate schema called APP_ADMIN which will take care of all of the DDL tasks.

Here’s my setup:

RTFM

Imagine you’re fairly new to Oracle and don’t have a lot of background information at your fingertips; then one day someone tells you to read the manual pages for the view dba_free_space. Look carefully at this sentence:

Note that if a data file (or entire tablespace) is offline in a locally managed tablespace, you will not see any extent information.

Can you spot the error ? Did you spot the error when you first read the sentence – or did you fill in the gap without noticing what you were doing ?

Let’s demonstrate the accuracy of the statement (simple cut-n-paste from an SQL*Plus session on 12.1.0.2 running in archivelog mode, and with a locally managed tablespace consisting of 4 (oracle managed) files on a filesystem):

Oracle 12cR2 Security - Listener Port

I downloaded Oracle 12cR2 from Oracle when it became available in March and installed a legacy SE2 database and also a single PDB multitenant database and started some investigations to discover and look at the new security features added in....[Read More]

Posted by Pete On 01/05/17 At 01:03 PM

12cR2 partial PDB backup

I had a recent question about the following mention from the 12cR2 Multitenant book, about Partial PDB backups:
CapturePArtialPDBBackup.
Here is an example in 12.2 with local undo to illustrate the answer, which may help to understand what is a partial PDB backup.

SQL Saturday 588 – May 20 in NYC

I’m really excited about speaking at SQL Saturday #588 at the Microsoft office in Times Square, I’ll be discussing Accelerating TDM Using Data Virtualization.  This is my favorite topic, because for the 20+ years that I worked as a database administrator (DBA), I ran into the same challenges time and again.

The challenges of data volume.