Changing The Number Of Oracle Database 12c Log Writers
In an Oracle Database 12c instance you will likely see multiple log writer (LGWR) background processes. When you first start the Oracle instance you will likely see a parent and two redo workers. This is a very big deal and something many of us have been waiting for - for many years!
While I'm excited about the change, if I can't control the number of LGWRs (more...)
The Perfect Gift For The Oracle DBA: Top 5 DBA T-Shirts
It's that time of year again and I can already hear it, "Dad, what do you want for Christmas?" This year I'm taking action. Like forecasting Oracle performance, I'm taking proactive
Like most of you reading this, you have a, let's say, unique sense of humor. I stumbled across the ultimate geek website that has an astonishing variety of t-shirts aimed at (more...)
Off May Not Be Totally Off: Is Oracle In-Memory Database 12c (220.127.116.11.0) Faster?
Most Oracle 12c installations will NOT be using the awesome Oracle Database in-memory features available starting in version 18.104.22.168.0. This experiment is about the performance impact of upgrading to 12c but disabling the in-memory features.
Every experiment I have performed comparing buffer processing rates, clearly shows any version of 12c performs better than 11g. (more...)
Is Oracle Database 12c (22.214.171.124.0) Faster Than Previous Releases?
I was wondering if the new Oracle Database 12c version 126.96.36.199.0 in-memory column store feature
will SLOW performance when it is NOT being used. I think this is a fair question because most Oracle Database systems will NOT be using this feature.
While the new in-memory column store feature is significant, with each new Oracle feature there is (more...)
Does Increasing An Oracle Background Process OS Priority Improve Performance?
Does increasing an Oracle Database background process operating system priority improve performance? As you might expect, the answer is, "It depends."
In this posting I will explain the results of an experiment where I increase the Oracle Database 12c log writer background processes operating system priority.
In my experiment I created a clear CPU bottleneck and the top wait event was log file parallel (more...)
11 Ways To Get Your Conference Abstract Accepted
|This is what happens when your abstract is selected!|
Ready for some fun!? It's that time of year again and the competition will be intense. The "call for abstracts" for a number of Oracle Database conferences are about to close.The focus of this posting is how you can get a conference abstract accepted.
As a mentor, Track Manager and active conference speaker I've been helping DBAs (more...)
Comparing SQL Execution Times From Different Systems
Suppose it's your job to identify SQL that may run slower in the about-to-be-upgrated Oracle Database. It's tricky because no two systems are alike. Just because the SQL run time is faster in the test environment doesn't mean the decision to upgrade is a good one. In fact, it could be disastrous.
For example; If a SQL statement runs 10 seconds in production and runs 20 seconds in (more...)
Top 7 Reasons Why Oracle Conferences Rock!
Why take the time and make the effort to attend an Oracle database conference or Oracle user group meeting? We're all busy, so there had better be some super good reasons to make the effort! For me, the benefits definitely exceed the cost.
There are many different conferences to choose from. There are professional conferences, leadership conferences, scientific conferences and business focused conferences. So why an Oracle Database (more...)
Top 7 Reasons Why Oracle Conferences Are A Waste Of Time
Want to turn a lame Oracle Database conference experience into a great one? You may not believe this, but I think Oracle conferences are a waste of time. That is, unless I take action.
I've been to hundreds of Oracle conferences, so I'm kind of an expert in this field.
Here is my "Top 7" list about why Oracle conferences are time suckers and (more...)
Watch Oracle Elapsed Time and Wall Time With Parallel Query
In my recent postings I wrote that when using the Oracle Database parallel query a SQL statement's wall time should be equal to its elapsed time divided by the number of parallel query slaves plus some overhead.
That may seem correct, but is it really true? To check I ran an experiment and posted the results here. The results are both obvious and illuminating.
What Is Oracle Elapsed Time And Wall Time With Parallelism Twist
In this post I'm focusing on Oracle Database SQL elapsed time, adding parallelism into the mix and then revisiting wall time. What initially seems simple can take some very interesting twists!
If you are into tuning Oracle Database systems, you care about time. And if you care about time, then you need to understand the most important time parameters: what they are, their differences, (more...)
Watch Oracle DB Session Activity With My Real-Time Session Sampler
Watching session activity is a great way to diagnose and learn about Oracle Database tuning. There are many approaches to this. I wanted something simple, useful, modifiable, no Oracle licensing
issues and that I could give away. The result is what I call the Oracle Real-Time Session Sampler (OSM: rss.sql).
The tool is simple to use. Based on a number filtering command line (more...)
What Is Oracle DB Time, DB CPU, Wall Time and Non-Idle Wait Time
If you are into tuning Oracle Database systems, you care about time. And if you care about time, then you need to understand the most important time parameters: what they are, their differences, how they relate to each other and how to use them in your performance tuning work.
The key Oracle Database time parameters are elapsed time, database time (DB Time), (more...)
Four Options For Oracle DBA Tuning Training
Oracle DBAs are constantly solving problems... mysteries. That requires a constant knowledge increase. I received more personal emails from my Oracle DBA Training Options Are Changing posting than ever before. Many of these were from frustrated, angry, and "stuck" DBAs. But in some way, almost all asked the question, "What should I do?"
In response to the "What should I do?" question, I came up with (more...)
Oracle DBA Training Options Are Changing
Training options for Oracle Database DBAs are changing. Generally, I don't think they are for the better. Companies don't value Oracle Database Administrators like they used to. And, it shows in the lack of their professional development investment.
When I travel a long way from home, I tend to get very reflective about life, death and beyond. On my way home from teaching an onsite two-day Oracle performance tuning (more...)
Have you ever wondered how the Oracle Database 12c (and earlier versions) determines the wait time when it has absolutely no control over how long the wait will take? If so, then read on!
The Back Story
Using wait time is part of an Oracle Time Based Analysis (OTBA). While Oracle process CPU consumption is a big part of the analysis, the other category is non-idle wait time.
You can see the two categories of (more...)
Does the Oracle Database 12c Log Writer Really Sleep For Three Seconds?
I have learned the part of Oracle Database performance tuning is checking if what you have been taught is actually true. What I'm writing about today has been done before in Oracle Database 10g and 11g, but I wanted to document this using 12c.
When I was first learning about the Oracle Database process architecture, the instructor said there are a number of (more...)
It's All About CPU But There Is NO CPU Bottleneck...
Diagnosing Oracle Database performance is like solving a puzzle. But what I really enjoy is coming up with performance solutions that are anti-intuitive for most people. You know, the ones when you can see people stop talking and actually think, "Why would Craig say that!?" In this posting, I delve into one of these situations.
Just over a month ago I received (more...)
OS Data Without An OS Prompt
Have you ever wanted to get OS data from within Oracle Database 12c/11g/10g and without being at the OS prompt? Have you ever wondered where v$osstat
gets it's data?
I have! It's the kind of stuff I think about all the time. In fact, I was so fascinated by what I found, I included the details in my online seminar, Utilization On Steroids
. It's that cool.