Golden Gate Activity Logging Tracing

A lot of customers of mine who are starting with Oracle Golden Gate have issues when it comes to troubleshooting Golden Gate. It is the most common question i get: “I have setup Golden Gate, it was working fine but now process X abandoned… now what do i do?”.  The OGG error log is a good starting point but is not always showing the real issue. There are a lot different way to obtain (more...)

ASSM Help

I’ve written a couple of articles in the past about the problems of ASSM spending a lot of time trying to find blocks with usable free space. Without doing a bit of rocket science with some x$ objects, or O/S tracing for the relevant calls, or enabling a couple of nasty events, it’s not easy proving that ASSM might be a significant factor in a performance problem – until you get to 12c Release 2 (more...)

An introduction to Performance Co Pilot, part 2.

This second blogpost on Performance Co Pilot or PCP in short is about visualisation. In case you haven’t read the first part, here it is, which describes how it works, why you should use it, and how you can install it.

Pmchart.
One way of visualising PCP is using the pmchart utility. The pmchart utility is installed via the pcp-gui package (yum install pcp-gui). The pmchart utility uses X to display a window and (more...)

The Best Non-Important Feature of 12cR2: History Command

So I’ve been using Oracle 12cR2 for a couple of weeks now (getting ready to ilOUG meetup in a few weeks), and I decided to share my favorite non-important feature of the new version: the History command for SQLPlus.

As most of you already know, I’m a huge fan of SQLcl (aka SQL Developer Command Line Interface). I’ve written about it a little, and talked about it in conferences a lot. In the last conference (more...)

Oracle Database Cloud (DBaaS) Performance – Part 3 – Storage – 12.2 Update

Recently I repeated the I/O related tests on a 12.2.0.1 instance for curiosity and was surprised by the fact that I consistently got significantly better results as on 11.2.0.4 and 12.1.0.2.

Now you're probably aware that the version 12.2 so far is "cloud-only", so I can't tell / test whether the version 12.2 is generically providing that increased performance or whether Oracle has optimized (more...)

PostgreSQL – An introduction

2017 – A year of learning !!

Today technology is changing at a very rapid speed and it’s very difficult to keep up to it but as said, it’s never too late to start something new. This year I plan to spend some time outside of Oracle and learn some new things.

I have started learning PostgreSQL and I want to take this platform to share my learning and to learn from others.  As this (more...)

Getting the most out of your Oracle database processor license in the cloud – if you dare…

Following up on the the Oracle doubled the costs for database licenses on MS Azure and partly on AWS post, I wondered with which setup on which cloud provider you would get the most bang out of an Oracle SE2 database processor license and what the recent change in Oracle licensing means especially for Azure users.

I’ve done an overly simple CPU benchmark test against Azure, AWS and Oracle cloud instances to get a rough (more...)

Oracle’s Cloud Licensing Change : Be Warned!

Over the last couple of years I’ve been doing talks about running Oracle databases in the cloud. In both my talks and articles I refer to the Licensing Oracle Software in the Cloud Computing Environment document. This morning I was reading a post on the Oak Table mailing list and someone* mentioned the document had been updated on 23-Jan-2017 and contained two rather interesting changes.

The Good

The document now explicitly mentions the difference between (more...)

Did You Know #18 – Order By Position

When writing a query with order by, we can use the column position instead of its name. This order by”trick” is easy to use, but should be handled carefully as it affects the order of rows if the column list changes. For example, these two are equal: select col1,col2,col3 from table1 order by col1,col2; select … Continue reading Did You Know #18 – Order By Position

“Back It Up!!!”


“Expectations is the place you must always go to before you get to where you're going.” 
― Norton Juster, The Phantom Tollbooth   

In a recent post in the Oracle General database forum the following question was asked:


Hi,

I have 3 schema's of almost equal sizes, off which only two are creating the backup's (Hot backup). One of the schema's is not creating any backup, by not creating I mean, the backup file that  (more...)

Performance comparison of different file formats and storage engines in the Hadoop ecosystem

TOPIC

This post reports performance tests for a few popular data formats and storage engines available in the Hadoop ecosystem: Apache Avro, Apache Parquet, Apache HBase and Apache Kudu. This exercise evaluates space efficiency, ingestion performance, analytic scans and random data lookup for a workload of interest at CERN Hadoop service.

 

INTRO

What new?

Oracle_DB1

Interesting news about the coming Oracle 12 Release.

Release Schedule of Current Database Releases (Doc ID 742060.1)

Take a look :-)


DBaaS Performance

I don’t know how I missed it but Randolf Geist has been doing writing a series of posts on the performance of Oracle’s DBaaS offering, using a series of long-running tests to capture not only raw performance figures but also an indication of consistency. You can find all of these tests with a search URL on his blog, but I’ve also created a little index here to make it easier for me to access (more...)

Basicfile LOBs

I wrote a short series a little while ago about some of the nasty things that can happen (and can’t really be avoided) with Basicfile LOBs and recently realised that it needed a directory entry so that I didn’t have to supply 6 URLs if I wanted to point someone to it; so here’s the catalogue:

Oracle Database Backup Service Fails with: ORA-19511: – KBHS-00715: HTTP error occurred ‘oracle-error’

I discovered a Oracle Cloud Database Backup failing with:

Starting backup at 2017/01/20 20:00:04
current log archived
RMAN-00571: ===========================================================
RMAN-00569: =============== ERROR MESSAGE STACK FOLLOWS ===============
RMAN-00571: ===========================================================
RMAN-03002: failure of backup plus archivelog command at 01/20/2017 20:00:08
ORA-19554: error allocating device, device type: SBT_TAPE, device name:
ORA-27023: skgfqsbi: media manager protocol error
ORA-19511: non RMAN, but media manager or vendor specific failure, error text:
 KBHS-00715: HTTP error occurred 'oracle-error'
KBHS-00712: ORA-28750 received from local  (more...)

Oracle doubled the costs for database licenses on MS Azure and partly on AWS

On January 23rd, 2017 Oracle published a new version of their “Licensing Oracle Software in the Cloud Computing Environment” document.

The current version is available here: http://www.oracle.com/us/corporate/pricing/cloud-licensing-070579.pdf

Previously, a virtual database server with 8 virtual cores running Oracle Enterprise Edition in an authorized cloud environment needed 8* 0.5 =4 processor licenses.

Now, the same server on MS Azure (all instance types) or on AWS servers that do NOT have hyperthreading (namely the (more...)

Distributed Deep Learning with Apache Spark and Keras

In the following blog posts we study the topic of Distributed Deep Learning, or rather, how to parallelize gradient descent using data parallel methods. We start by laying out the theory, while supplying you with some intuition into the techniques we applied. At the end of this blog post, we conduct some experiments to evaluate how different optimization schemes perform in identical situations.

Who Decommissioned My Enterprise Manager Agent?

I prefer to write blog posts about the interesting questions on OTN. This blog post is one of them. There are usually more than one EM admins managing the systems, and you may want to track other users’ activity. Enterprise Manager Cloud Control provides auditing mechanism called “comprehensive auditing”. It’s not enabled by default for all actions because it may consume a lot of disk space.

If you want to enable it for all actions, (more...)

TCP RMEM Fault in Delphix Target on AWS

So you’ve deployed targets with Delphix on AWS and you receive the following error:

It’s only a warning, but it states that you’re default of 87380 is below the recommended second value for the ipv4.tcp.rmem property.  Is this really an issue and do you need to resolve it?  As usual, the answer is “it depends” and its all about on how important performance is to you.

(more...)

The SQL Loader log file … as data

I had an interesting AskTom question recently where the poster was using SQL Loader to load in tables, but wanted to be able to analyze the resultant log file after execution.  And of course, what better way to analyze..well…anything…than with a database and some SQL. 

So we need to be able to access the log file as a table, and an external table is perfect for that, so let’s start there.

Here’s (more...)