Search

Top 60 Oracle Blogs

Recent comments

December 2016

My new role

Today I can finally tell you the good news on my new role. December 8th was my last day at Oracle. So what was the good news? I already have a new job, as a technical architect with a small company called archTIS. I saw the job advertised on LinkedIn and applied, spent an hour and a half in a phone interview the next day, got called in to meet the CEO the day after and he offered me the job on the spot! I’ve already started in the new role, and it looks both exciting AND challenging. Couldn’t be more happy as a result. </p />
</p></div>

    	  	<div class=

Oracle Security And Merry Xmas And A Happy New Year

I want to wish all readers of my site and this blog a very happy Christmas and a very prosperous New Year!! It has been some time since my last blog post; that's because we have been incredibly busy on....[Read More]

Posted by Pete On 16/12/16 At 08:54 PM

Friday Philosophy – Is a “Free Lunch” Only Ever a Mirage? Look Closer!

Nearly all of us have heard (or even used) the phrase “There is no such thing as a free lunch” and we know what it means – if something of value is provided for no up-front cost, you are paying for it in some other way. According to the Wikipedia entry for it the phrase could have originated from US bars that offered a free meal with a drink, but the meal was salty and so made you want to drink more. Now you know why some up-market bars offer free salty nibbles, it’s so they can sell you more beer and the extra profit is more than peanuts.

Advanced Replication

Long before Streams, long before Goldengate, if you want to keep data between sites synchronised in some fashion, or even allow sites to independently update their data, there was the Advanced Replication facility in Oracle.  An “extension” of the concept of simple materialized views (or snapshots as they were called then), you could design complete replicated environments across Oracle databases.

But it was a non-trivial exercise to do this.  You had to be familiar with replication groups, replication objects, replication sites, master groups, master sites,  master definition sites, deferred transactions, quiescing, updatable materialized views, replication catalogs, conflict resolution…the list goes on an on.

Creating a RAC 12.1 Data Guard Physical Standby environment (1)

I have just realised that the number of posts about RAC 12c Release 1 on this blog is rather too small. And since I’m a great fan of RAC this has to change :) In this mini-series I am going to share my notes about creating a Data Guard setup on my 2 node 12.1.0.2.161018 RAC primary + identical 2 node RAC standby system in the lab.

NOTE: As always, this is just a demonstration using VMs in my lab, based on my notes. Your system is most likely different, so in real-life you might take a different approach. The techniques I am using here were suitable for me, and my own small scale testing. I tried to make sure they are valid, but you may want to allocate more resources in your environment. Test, test, test on your own environment on test kit first!

The lab Environment

My environment consists of the following entities:

Oracle ACE Director Alumni Status

I've recently requested to be removed from the Oracle ACE program and move to the "Alumni" status.

I've already felt for a quite a while now that my area of expertise and interest as well as my public profile (no Twitter etc.) is no longer really a good fit to the ACE program.

The most recent changes to the ACE program then just have made my decision easier to step back.

All the best to the ACE program and thanks for the support during the last eight years!

This decision won't really influence what I'll do in the future - I'll continue to publish notes and videos about things I find interesting about Oracle database technology, the same way I did before - probably with a little less pressure to maintain a certain level of output.

GNW05 – Extending Databases With the Full Power of Hadoop: How Gluent Does It

It’s time to announce the next webinar in the Gluent New World series. This time I will deliver it myself (and let’s have some fun :-)

Details below:

GNW05 – Extending Databases With the Full Power of Hadoop: How Gluent Does It

Why does my full table scan take 10x longer today ?!

Every so often a DSS query that usually takes 10 minutes ends up taking over an hour.  (or one that takes an hour never seems to finish)

Why would this happen?

When investigating the DSS query, perhaps with wait event tracing,  one finds that the query which is doing full table scans and should be doing large multi-block reads and waiting for “db file scattered read” is instead waiting for single block reads, ie “db file sequential read”.  What the heck is going on?

Sequential reads during a  full table scan scattered read query is a classic sign of reading rollback and reading rollback can make that minute(s) full table scan take hours.

Index Compression

Richard Foote has published a couple of articles in the last few days on the new (licensed under the advanced compression option) compression mechanism in 12.2 for index leaf blocks. The second of these pointed out that the new “high compression” mechanism was even able to compress single-column unique indexes – a detail that doesn’t make sense and isn’t allowed for the older style “leading edge deduplication” mechanism for index compression.