Skip navigation.

Pythian Group

Syndicate content
Official Pythian Blog - Love Your Data
Updated: 16 hours 59 min ago

OakTable World at IOUG COLLABORATE15

Thu, 2015-04-02 18:52

Update history:
5-Apr: WIT panel added, Alex removed, Gwen and Pete schedule shifted.
11-Apr: Gwen and Pete swapped sessions.
13-Apr: Jonathan off lightning talks.

Guess what? OakTable World at IOUG C15 is happening again! Last year, we had awesome sessions and wonderful attendees. The sessions were so successful, in fact, that we needed a bigger room this year (there were other reasons too, but hey we can fit more people now!).

What: OakTable World C15
When: Wednesday, April 15, 2015, 8:00am – 5:30pm
Where: Mandalay Ballroom K

I really hope that, if you are reading this, you are planning to attend COLLABORATE 15 – IOUG Forum at the Mandalay Bay Resort & Casino in Vegas from April 12-16. If you haven’t yet planned your trip, this might just help you make the call. You know you want to be there!

OakTable Network will be holding its highly anticipated OakTable World during COLLABORATE 15! As always, IOUG was able to provide a room for us to use for the whole day (and boy what a big room it is!). The agenda is determined by the OakTable speakers, who choose topics they are passionate about. And if history is any indicator, these are also the topics you really want to hear about.

For those of you who aren’t familiar with OakTable World, Mogens Nørgaard started it as an underground event during Oracle OpenWorld—somewhere between 2007 and 2009. After several successful years and increasing popularity, the event became known as OakTable World during OOW12 and OOW13. Last year, we hosted OTWC14 at IOUG COLLABORATE 14 in Vegas. Needless to say, it was a success. So…Vegas here we come again!

Thank you to all the great companies who have sponsored this event over the years—you know who you are. This year, the usual suspects have pitched in to make it happen again—Pythian, Enkitec and Delphix. Once again, we will be printing unique t-shirts with cool graphics and awesome sponsors’ logos. Be part of history!

The OTW sessions are (mostly) aligned with conference sessions, except we start a tad later (you will appreciate it) and we’ve shifted a few sessions by 15 minutes to pack in as many as possible. Don’t worry, though, we don’t run anything during lunch or afternoon nap. :)

The current schedule is below, but check back regularly as it may change due to random events.

Time Presenter Title 8:10-8:15 someone authorized Opening Notes 8:15-9:00 Tim Gorman Augmenting SQL Monitor 9:15-10:15 guest session Women in Technology Panel 10:30-11:10 Pete Sharman Knowledge Sharing – Why Do It? 11:15-12:00 Gwen Shapira Kafka for DBAs – Because Inquiring Minds Need to Know 14:00-15:00 see below Lightning Talks! 15:15-16:15 Cary Millsap The Go/No-Go Matrix for Thinking Clearly About Testing 16:30-17:30 Jared Still Knowledge Builds Intuition

Lightning Talks are 10-minute presentations done in a rapid-fire fashion. They are always a huge success—you’ve got to be there! They may be technical, motivational, or inspirational, but regardless they are always cool speeches. The sequence of the talks may change, but everything will be presented within the hour.

Presenter Lightning Talk Kyle Hailey What is DevOps Kellyn Pot’Vin-Gorman SQLT in AWR Warehouse Alex Gorbachev #100miles Pete Sharman SnapClones++ Jonah H. Harris Performing MongoDB-Compatible NoSQL on Top of Oracle SQL

The OakTable Network folks and other great people will be hanging around, so make sure you drop by! This is an awesome place to grow your network. Remember that the presenters determine the agenda. Our passion to share and educate is what drives us. Come join us.

Vegas, here we come!

Categories: DBA Blogs

Pillars of Powershell #2: Commanding

Tue, 2015-03-31 07:28
Introduction

This is the second blog post as a continuance in the series on the Pillars of PowerShell. In the initial blog post we went over the various interfaces that can be used to work with PowerShell. In this blog post we are going to start out by going through a few terms you might find when you start reading up on PowerShell. Otherwise, I will go over three of the cmdlets you will find can be used to discover and get documentation on the cmdlets available to you in PowerShell.

Pillar 2: Commanding

The following are a few terms I will use throughout this series, and ones you might find referenced in any reading material, which I wanted to introduce so we start out on the same page:

  • Session
    When you open PowerShell.exe or PowerShell_ISE.exe it will create a session for you, essentially a blank slate for you to build and create. You can think of this as a query window within the SQL Server Management Studio.
  • Cmdlets
    Pronounced “command-lets”, these are the bread and butter of PowerShell that allow you to do things from getting information or manipulating it. Microsoft has coined the format of Verb-Noun for the cmdlets and it has pretty much stuck. Each version of PowerShell as it is released comes with additional cmdlets, and then product teams like SQL Server and Active Directory are also releasing cmdlets to allow you to interact with them through PowerShell. Each time you open a session with PowerShell there are a set of core cmdlets that are automatically loaded for you.
  • Module
    A module is basically just a set of cmdlets that can be added within your session of PowerShell. When you load a module into your session, the commands are then made available to you. If you close that session and open a new one, you will then have to reload that module to access the commands again.
  • Objects
    PowerShell is based on .NET, this is what is behind the scenes more or less, thus with .NET being an object oriented language PowerShell treats the data that is returned as objects. So, if I use a cmdlet to return the processes running on a machine, each process that it returns is as an object.
  • The Pipeline
    This is named after the symbol used to connect cmdlets together, “|” (vertical bar on your keyboard). You can think of this like a train, each train car represents a set of objects and each car you pass it through can do something to each object until you reach the end.
  • PowerShell Profile
    This is basically the ability to customize your PowerShell session each time you open or start PowerShell. You can do things such as pre-load modules, create custom bits of PowerShell code for reuse or easy access, and many other things. I would compare this to your profile in Windows that keeps up with things like the icons or applications you have pinned to the taskbar or the default browser.

Now I want to take you through a few core cmdlets that are used most commonly to discover what is available in the current version of PowerShell or the module you might be working with in it. I tend to use these commands almost every time I open PowerShell. I do not try to memorize everything, especially when I can look it up so quickly in PowerShell.

Get-Command

This cmdlet does exactly what you think it does, gets a list of commands that are available in your current PowerShell session. You can use the parameters of this cmdlet to filter the list down to what interest you, say all the “get” cmdlets:

Get-Command -Verb Get -CommandType Cmdlet
p2_get-command-verb-get Get-Help

Now you might be wondering where the documentation is for all of the cmdlets you saw using Get-Command? Where is the Books Online equivalent to what you get with SQL Server? Well unlike SQL Server you can actually get the documentation via the cmdlet Get-Help. This cmdlet can return the information to you or you can use a parameter to open it up in the browser, if it is available. So for example one of the best things to look up documentation on initially is the Get-Help cmdlet itself:

Get-Help

The output of this command is good to read through but the main items I want to pull out are three particular parameters:

  1. Online: This will take you to the TechNet page of the documentation for the cmdlet. This may not work with every cmdlet you come across but if Microsoft owns it there should be something.
  2. Examples: This is going to provide a few examples and descriptions of how you can use the cmdlet and the more common parameters.
  3. Full: This will show you pretty much what document is online. This just keeps you in PowerShell instead of view it in the browser.

So let me try bringing up the examples of the Get-Help cmdlet itself:

Get-Help Get-Help -Examples
p2_get-help-examples

If you are using Windows 7 OS or higher, you may receive something similar to this screenshot. This is something that was added in PowerShell version 3.0, the cmdlet Update-Help. This cmdlet is used to actually update the help files on a computer as needed. In the event Microsoft updates the help files, or the online TechNet page, you can use this to download a current version of it. Microsoft has moved to this method in place of trying to do the updates locally with cumulative updates or service packs. It does require Internet access to execute the cmdlet. If your machine is not on the Internet you can download them from Microsoft’s download center. In order to fix the above message I just need to issue the command: Update-Help.

You should see a progress bar as shown below while it is running through updating all the files (which that progress bar is actually done using PowerShell):

p2_update-help

I ended up getting two errors for certain modules and this is because I am not running the cmdlet with elevated privileges. If you open PowerShell.exe with the “Run As Administrator” option and then execute the cmdlet again it will be able to update all help files without error.

Now if you run the previous command again you should see the actual examples, although if you notice it can be annoying to try and scroll back up to read all that information. A tidbit I did not know about right away was that there is a parameter in Get-Help that opens up a separate window, which makes it easier to read called, “-ShowWindow“. It is basically the “-Full” output but with the option to filter out sections that do not interest you.

Get-Help Get-Help -ShowWindow
p2_get-help-showwindow

You actually can use Get-Help to search for cmdlets as well. I tend to do this more than trying to use Get-Command just because it is a bit quicker. You can just issue something like this to find all the Get” cmdlets:

Get-Help get*

One more thing about the help system in PowerShell, it also includes things called “about files” that are basically concept topics that go deeper into certain areas. They offer a wealth of information and you can also get to these online. Something for you to try on your own to see what is available is just issue this command:

Get-Help about*
Get-Member

This cmdlet is a little gem that you will use more than anything. If you pipe any cmdlet (or one-liner) to Get-Member it will provide you a list of the properties or methods available to you for the object(s) passed. This cmdlet also includes a filter of “-MemberType” that I can use to only return the properties available to me. The properties are those that we can “select” to return as output or pass to other cmdlets down the pipe.

Get-Command | Get-Member -MemberType Property
Out-GridView

I am only going to touch on this cmdlet. It can be used to output objects into a table like view, that also offers some filtering attributes too. There are a few different Out-* cmdlets that are available to you for outputting information to various destinations. You can find these using the Get-Command or Get-Help cmdlets. To use Out-GridView on a Windows Server OS you will have to add the PowerShell ISE feature. You will get an error stating as much if you do not.

Get-Command | Out-GridView

get-comand-get-member-out-gridview Summary

The three cmdlets Get-CommandGet-Help, and Get-Member that I spoke on above are ones I think you should become very familiar with and explore them deeply. Once you master using these it will provide you the ability to find out anything and everything about a cmdlet or module that you are trying to use. When you start working with various modules such as Azure or SQL Server PowerShell (SQLPS) these cmdlets are quite useful in discovering what is available.

Categories: DBA Blogs

Pillars of PowerShell #1: Interacting

Tue, 2015-03-31 06:55
Introduction

PowerShell is a tool that if adopted can be used to help automate and standardize processes in your Windows and SQL Server environment (among other things). This blog series is intended to show you some of the basics (not all of them) that will get you up and running with PowerShell. I say not all of them, because there are areas in PowerShell that you can go pretty deep in, just like SQL Server. I want to just give you the initial tools to get you on your way to discovering the awesomeness within PowerShell. I decided to go with a Greek theme, and just break this series up into pillars. In this first blog post I just wanted to show you the tools that are available to allow you to interact with PowerShell itself.

Pillar 1: Interacting

Interacting with PowerShell is most commonly issuing commands directly on the command line interface (CLI), the step above that would be building out a script that contains multiple commands. The first two options are available “out-of-the-box” on a Windows machine that has PowerShell installed. After this, you have a few third party options available to you that I will point out.

  1. PowerShell.exe
    This is the command prompt (or console as some may call it) that most folks will spend their day-to-day life entering what are referred to as “one-liners”. This is the CLI for PowerShell. You can access this in Windows by going through the Start Menu, or just type it into the Run prompt.
    powershell.exe
  2. PowerShell_ISE.exe
    This is the PowerShell Integrated Scripting Environment and is included in PowerShell 2.0 and up. This tool gives you the ability to have a script editor and CLI in one place. You can find out more about this tool and the various features that come with each version here. You can access this similar to the same way you would PowerShell.exe. In Windows Server 2008 R2 and above though this it is a Windows Feature that has to be added or activated before you can use it.
    powershell_ise
  3. Visual Studio (VS) 2013 Community Edition + PowerShell Tools for Visual Studio 2013
    VS 2013 Community is the free version of Visual Studio that includes the equivalent functionality of Visual Studio Professional Edition. Microsoft opened up the door for many things when they did this, the main one being that you can now develop PowerShell scripts along side your C# or other .NET projects. Adam Driscoll (PowerShell MVP) developed and released an add-on specifically for VS 2013 Community that you can get from GitHub, here.
  4. Third party ISE/Editors
    The following are the main players in the third party offerings for PowerShell ISE or script editors. I have tried all of them before, but since they only exist on the machine you install them on I tend to stick with what is in Windows. They have their place and if you begin to develop PowerShell heavily (e.g. full project solutions) they can be very useful in the management of your scripts:

Summary

This was a fairly short post that just started out with showing you what your options are to start working and interacting with PowerShell. PowerShell is a fun tool to work with and discover new things that it can do for you. In this series I will typically stick with using the CLI (PowerShell.exe) for examples.

One more thing to point out is the versions of PowerShell currently released (as of this blog post) are 2.0, 3.0, and 4.0. The basic commands I am going to go over will work in any version, but where specific nuances exist between each version I will try to point out if needed.

Categories: DBA Blogs

PowerShell Script to Manipulate SQL Server Backup Files

Tue, 2015-03-31 06:39
Scenario

I use Ola Hallengren’s famous backup solution to back up my SQL Server databases. The destination for full backups is a directory on local disk; let’s say D:\SQLBackup\

If you are familiar with Ola’s backup scripts, you know the full path for backup file looks something like:

D:\SQLBackup\InstanceName\DatabaseName\FULL\InstanceName_DatabaseName_FULL_yyyymmdd_hhmiss.bak

Where InstanceName is a placeholder for the name of the SQL server instance, similarly, DatabaseName is for the Database Name.

Problem

Depending upon my retention period settings, I may have multiple copies of full backup files under the said directory. The directory structure is complicated too (backup file for each database is under two parent folders). I want to copy the latest backup file (only) for each database to a UNC share and rename the backup file scrubbing everything but the database name.

Let’s say the UNC path is \\RemoteServer\UNCBackup. The end result would have the latest full backup file for all the databases copied over to \\RemoteServer\UNCBackup with files containing their respective database names only.

Solution

I wrote a PowerShell script to achieve the solution. This script can be run from a PowerShell console or PowerShell ISE. The more convenient way would be to use PS subsystems and schedule a SQL Server agent job to run this PowerShell script. As always, please run this on a test system first and use at your own risk. You may want to tweak the script depending upon your requirement.

 

<#################################################################################

   

Script Name: CopyLatestBackupandRename.ps1                       

Author     : Prashant Kumar                           

Date       : March 29th, 2015

   

Description: The script is useful for those using Ola Hallengren’s backup solution.

             This script takes SQL Server full backup parent folder as an input,

             a remote UNC path as another input and copies the latest backup file

             for each database, renames the backup file to the remote UNC path.

 

 

This Sample Code is provided for the purpose of illustration only and is not

intended to be used in a production environment. THIS SAMPLE CODE AND ANY

RELATED INFORMATION ARE PROVIDED “AS IS” WITHOUT WARRANTY OF ANY KIND, EITHER

EXPRESSED OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE IMPLIED WARRANTIES OF

MERCHANTABILITY AND/OR FITNESS FOR A PARTICULAR PURPOSE.

##################################################################################>

 

#Clear screen

cls

 

#Specify Parent folder where Full backup files are originally being taken

$SourcePath = ‘D:\SQLBackup\InstanceName’

 

#Specify UNC path ot network share where backup files has to be copied

$UNCpath = ‘\\RemoteServer\UNCBackup’

 

#Browse thru subfolders (identical to database names) inside $SourcePath

$SubDirs = dir $SourcePath -Recurse | Where-Object {$_.PSIsContainer} | ForEach-Object -Process {$_.FullName}

 

#Browse through each sub-drorectory inside parent folder

ForEach ($Dirs in $SubDirs)

       {

    #List recent file (only one) within sub-directories

       $RecentFile = dir $Dirs | Where-Object {!$_.PSIsContainer} | Sort-Object {$_.LastWriteTime} -Descending | Select-Object -First 1

      

    #Perform operation on each file (listed above) one-by-one

       ForEach ($File in $RecentFile)

              {

       

              $FilePath = $File.DirectoryName

              $FileName = $File.Name

        $FileToCopy=$FilePath+‘\’+$FileName

        $PathToCopy=($filepath -replace [regex]::Escape($SourcePath), $UNCpath)+‘\’

       

        #Forecfully create the desired directory structure at destination if one doesn’t exist

        New-Item -ItemType Dir -Path $PathToCopy -Force

 

        #Copy the backup file

        Copy-Item $FileToCopy $PathToCopy

 

        #Trim the date time from the copied file name, store in a variable

        $DestinationFile = $PathToCopy+$FileName

        $RenamedFile = ($DestinationFile.substring(0,$DestinationFile.length-20))+‘.bak’

 

        #Rename the copied file

        Rename-Item $DestinationFile $RenamedFile

 

        }

             

       }

 

 

 

Categories: DBA Blogs

SQL Server 2012 SP2 Cummulative Update 5

Tue, 2015-03-31 06:20

Hey folks,

Microsoft released the 5th Cummulative Update for SQL Server 2012 SP2. This update package contains fixes for 27 different issues, distributed as follows:

 

CU5

 

One very important issue that was fixed on this CU release was KB3038943 –   Error 4360 when you restore the backup of secondary replica to another server in AlwaysOn Availability Groups.

If you use SQL Server 2012 SP2 Always On and you offload your log backups to the secondary node it is recommended that you apply this patch!

The full Cummulative Update release and the download links can be found here: http://support.microsoft.com/en-us/kb/3037255/en-us

 

Categories: DBA Blogs

Log Buffer #416, A Carnival of the Vanities for DBAs

Mon, 2015-03-30 12:29

This log buffer edition sprouts from the beauty, glamour and intelligence of various blog posts from Oracle, SQL Server, and MySQL.

Oracle:

Oracle Exadata Performance: Latest Improvements and Less Known Features

Exadata Storage Index Min/Max Optimization

Oracle system V shared memory indicated deleted

12c Parallel Execution New Features: Concurrent UNION ALL

Why does index monitoring makes Connor’s scratch his head and charges off to google so many times.

SQL Server:

Learn how to begin unit testing with tSQLt and SQL Server.

‘Temporal’ tables contain facts that are valid for a period of time. When they are used for financial information they have to be very well constrained to prevent errors getting in and causing incorrect reporting.

As big data application success stories (and failures) have appeared in the news and technical publications, several myths have emerged about big data. This article explores a few of the more significant myths, and how they may negatively affect your own big data implementation.

When effective end dates don’t align properly with effective start dates for subsequent rows, what are you to do?

In order to automate the delivery of an application together with its database, you probably just need the extra database tools that allow you to continue with your current source control system and release management system by integrating the database into it.

MySQL:

Ronald Bradford on SQL, ANSI Standards, PostgreSQL and MySQL.

How to Manage the World’s Top Open Source Databases: ClusterControl 1.2.9 Features Webinar Replay

A few interesting findings on MariaDB and MySQL scalability, multi-table OLTP RO

MariaDB: The Differences, Expectations, and Future

How to Tell If It’s MySQL Swapping

Categories: DBA Blogs

Pythian at Collaborate 15

Fri, 2015-03-27 15:05

Make sure you check out Pythian’s speakers at Collaborate 15. Stop by booth #1118 for a chance meet some of Pythian’s top Oracle experts, talk shop, and ask questions. This many Oracle experts in one place only happens once a year, have a look at our list of presenters, we think you’ll agree.

Click here to view a PDF of our presenters

 

Pythian’s Collaborate 15 Presenters | April 12 – 16 | Mandalay Bay Resort and Casino, Las Vegas

 

Christo Kutrovsky | ATCG Senior Consultant | Oracle ACE

 

Maximize Exadata Performance with Parallel Queries

Wed. April 15 | 10:45 AM – 11:45 AM | Room Banyan D

 

Big Data with Exadata

Thu. April 16 | 12:15 PM – 1:15 PM | Room Banyan D

 

Deiby Gomez Robles | Database Consultant | Oracle ACE

 

Oracle Indexes: From the Concept to Internals

Tue. April 14 | 4:30 PM – 5:30 PM | Room Palm C

 

Marc Fielding | ATCG Principal Consultant | Oracle Certified Expert

 

Ensuring 24/7 Availability with Oracle Database Application Continuity

Mon. April 13 | 2:00 PM – 3:00 PM | Room Palm D

 

Using Oracle Multi-tenant to Efficiently Manage Development and Test Databases

Tue. April 14 | 11:00 AM – 12:00 PM | Room Palm C

 

Maris Elsins | Oracle Application DBA | Oracle ACE

Mining the AWR: Alternative Methods for Identification of the Top SQLs in Your Database

Tue. April 14 | 3:15 PM – 4:15 PM | Room Palm B

 

Ins and Outs of Concurrent Processing Configuration in Oracle e-Business Suite

Wed. April 15 | 8:00 AM – 9:00 AM | Room Breakers B

 

DB12c: All You Need to Know About the Resource Manager

Thu. April 16 | 9:45 AM – 10:45 AM | Room Palm A

 

Alex Gorbachev | CTO | Oracle ACE Director

 

Using Hadoop for Real-time BI Queries

Tue, April 14 | 9:45 AM – 10:45 AM | Room Jasmine E

 

Using Oracle Multi-tenant to Efficiently Manage Development and Test Databases

Tue, April 14 | 11:00 AM – 12:00 PM | Room Palm C

 

Anomaly Detection for Database Monitoring

Thu, April 16 | 11:00 AM – 12:00 PM | Room Palm B

 

Subhajit Das Chaudhuri | Team Manager

 

Deep Dive: Integration of Oracle Applications R12 with OAM 11g, OID 11g , Microsoft AD and WNA

Tue, April 14 | 3:15 PM – 4:15 PM | Room Breakers D

 

Simon Pane | ATCG Senior Consultant | Oracle Certified Expert

 

Oracle Service Name Resolution – Getting Rid of the TNSNAMES.ORA File!

Wed, April 15 | 9:15 AM – 10:15 AM | Room Palm C

 

René Antunez | Team  Manager | Oracle ACE

 

Architecting Your Own DBaaS in a Private Cloud with EM12c

Mon. April 13 | 9:15 AM – 10:15 AM | Room Reef F

 

Wait, Before We Get the Project Underway, What Do You Think Database as a Service Is…

Mon, Apr 13 | 03:15 PM – 04:15 PM | Room Reef F

 

My First 100 days with a MySQL DBMS

Tue, Apr 14 | 09:45 AM – 10:45 AM | Room Palm A

 

Gleb Otochkin | ATCG Senior Consultant | Oracle Certified Expert

 

Your Own Private Cloud

Wed. April 15 | 8:00 AM – 9:00 AM | Room Reef F

 

Patching Exadata: Pitfalls and Surprises

Wed. April 15 | 12:00 PM – 12:30 PM | Room Banyan D

 

Second Wind for Your exadata

Tue. April 14 | 12:15 PM – 12:45 PM | Room Banyan C

 

Michael Abbey | Team Manager, Principal Consultants | Oracle ACE

 

Working with Colleagues in Distant Time Zones

Mon, April 13 | 12:00 PM – 12:30 PM | Room North Convention, South Pacific J

 

Manage Referential Integrity Before It Manages You

Tue, April 14 | 2:00 PM – 3:00 PM | Room Palm C

 

Nothing to BLOG About – Think Again

Wed, April 15 | 7:30 PM – 8:30 PM | Room North Convention, South Pacific J

 

Do It Right; Do It Once. A Roadmap to Maintenance Windows

Thu, April 16 | 11:00 AM – 12:00 PM | Room North Convention, South  Pacific J

Categories: DBA Blogs

Oracle Database 12c In-Memory Q&A Webinar

Thu, 2015-03-26 09:21

Today I will be debating Oracle 12c’s In-Memory option with Maria Colgan of Oracle (aka optimizer lady, now In-Memory lady).

This will be in a debate form with lots of Q&A from the audience. Come ask the questions you always wanted to ask.

Link to register and attend:
https://attendee.gotowebinar.com/register/7874819190629618178

Starts at 12:00pm EDT.

Categories: DBA Blogs

Free Apache Cassandra Training Event in Cambridge, MA March 23

Fri, 2015-03-20 14:24

I’ll be speaking, along with DataStax and Microsoft representatives at Cassandra Essentials Day this coming Monday (March 23) in Cambridge. MA. This free training event will cover the basics of Apache Cassandra and show you how to try it out quickly, easily, and free of charge on the Azure cloud. Expect to learn about the unique aspects of Cassandra and DataStax Enterprise and to dive into real-world use cases.

Space is limited, so register online to reserve a spot.

Categories: DBA Blogs

My Co-op Experience at Pythian

Fri, 2015-03-20 06:30
That's me in front of our office. I promise there is a bigger Pythian logo!

That’s me in front of our office. I promise there is a bigger Pythian logo!

Unlike most other engineering physics students at Carleton who prefer to remain within the limits of engineering, I had chosen to apply for a software developer co-op position at Pythian in 2014. For those of you who do not know much about the engineering physics program (I get that a lot and so I will save you the trip to Google and tell you), this is how Stanford University describes their engineering physics program: “Engineering Physics prepares students to apply physics to tackle 21st century engineering challenges and to apply engineering to address 21st century questions in physics.” As you can imagine, very little to do with software development. You might ask, then why apply to Pythian?

Programming is changing the way our world functions. Look at the finance sectors: companies rely on complicated algorithms to determine where they should be investing their resources which in turn determines the course of growth for the company. In science and technology, algorithms help us make sense of huge amounts of unstructured data which would otherwise take us years to process, and help us understand and solve many or our 21st century problems. Clearly, learning how to write these algorithms or code cannot be a bad idea, rather, one that will be invaluable. A wise or a not so wise man once said, (you will know what I mean if you have seen the movie iRobot): “If you cannot solve a problem, make a program that can.” In a way, maybe I intend to apply physics to tackle all of 21st century problems by writing programs. (That totally made sense in my head).

Whatever it might be, my interest in programming or my mission to somehow tie physics, engineering, and programming together, I found myself looking forward to an interview with Pythian. I remember having to call in for a Skype interview. While waiting for my interviewers to join the call, I remember thinking about all the horror co-op stories I had heard: How you will be given piles of books to read over your work term (you might have guessed from this blog so far, not much of a reader, this one. If I hit 500 words, first round’s on me!). Furthermore, horror stories of how students are usually labeled as a co-op and given no meaningful work at all.

Just as I was drifting away in my thoughts, my interviewers joined the call. And much to my surprise they were not the traditional hiring managers in their formal dresses making you feel like just another interviewee in a long list of interviewees. Instead they were warm and friendly people who were genuinely interested in what I could offer to the company as a co-op student. The programming languages I knew, which one was my favourite, the kind of programs I had written, and more. They clearly stated the kind of work I could expect as a co-op student, which was exactly the same kind of work that the team was going to be doing. And most importantly, my interviewers seemed to be enjoying the kind of work they do and the place they work at.

So, when I was offered the co-op position at Pythian. I knew I had to say yes!

My pleasant experience with Pythian has continued ever since. The most enjoyable aspect of my work has been the fact that I am involved in a lot of the team projects which means I am always learning something new and gaining more knowledge each day, after each project. I feel that in an industry like this, the best way to learn is by experience and exposure. At Pythian that is exactly what I am getting.

And if those are not good enough reasons to enjoy working for this company, I also have the privilege of working with some extremely experienced and knowledgeable people in the web development industry. Bill Gates had once suggested that he wants to hire the smartest people at Microsoft and surround himself with them. This would create an environment where everyone would learn from each other and excel in their work. And I agree with that. Well now if you are the next Bill Gates, go ahead, create your multibillion dollar company and hire the best of the best and immerse yourself in the presence of all that knowledge and intelligence. But I feel I have found myself a great alternative, a poor man approach, a student budget approach or whatever you want to call it, take full advantage of working with some really talented people and learn as much as you can.

Today, five months into my yearlong placement with Pythian, I could not be more sure and proud of becoming a part of this exciting company, becoming a Pythianite. And I feel my time spent in this company has put me well in course to complete my goal of tying physics, engineering and programming together.

Categories: DBA Blogs

Log Buffer #415, A Carnival of the Vanities for DBAs

Fri, 2015-03-20 06:25

This Log Buffer Edition covers the Oracle, SQL Server and MySQL with a keen look on the novel ideas.

Oracle:

The case was to roll forward a physical standby with an RMAN SCN incremental backup taken from primary.

Oracle Database 12c: Smart upgrade

This blog covers how to specify query parameters using the REST Service Editor.

Production workloads blend Cloud and On-Premise Capabilities

ALTER DATABASE BEGIN BACKUP and ALTER DATABASE END BACKUP

SQL Server:

Mail Fails with SQLCMD Error

How to get Database Design Horribly Wrong

Using the ROLLUP, CUBE, and GROUPING SETS Operators

The Right and Wrong of T-SQL DML TRIGGERs (SQL Spackle)

How converting extensive, repetitive code to a data-driven approach resolved a maintenance headache and helped identify bugs

MySQL:

Distributing innodb tables made simpler!

Choosing a good sharding key in MongoDB (and MySQL)

Update a grails project from version 2.3.8 to version 2.4.4

MySQL Enterprise Backup 3.12.0 has been released

If table is partitioned it makes it easy to maintain. Table has grown so huge and the backups are just keep running long then probably you need to think of archival or purge.

Categories: DBA Blogs

Using strace to debug application errors in linux

Fri, 2015-03-20 06:24

strace is a very useful tool which traces system calls and signals for a running process. This helps a lot while debugging application level performance issues and bugs. Aim of this post is to demonstrate the power of strace in pinning down an application bug.

I came across an issue in which nagios was sending the following alerts for a RHEL6 system.

***** Nagios ***** Notification Type: PROBLEM Service: NTP Host: xxxxx Address: xx.xx.xx.xx State: UNKNOWN Date/Time: Tue Feb 17 10:08:36 EST 2015 Additional Info: cant create socket connection

On manually executing the nagios plugin on the affected system, we can see that the command is not running correctly.

# /usr/lib64/nagios/plugins/check_ntp_time -H localhost -w 1 -c 2
can’t create socket connection

I ran strace on the command. This would create a file /tmp/strace.out with strace output.

# strace -xvtto /tmp/strace.out /usr/lib64/nagios/plugins/check_ntp_time -H localhost -w 1 -c 2

Following are the options which I passed.

-x Print all non-ASCII strings in hexadecimal string format.
-v Print unabbreviated versions of environment, stat, termios, etc. calls. These structures
are very common in calls and so the default behavior displays a reasonable subset of struc?
ture members. Use this option to get all of the gory details.
-tt If given twice, the time printed will include the microseconds.
-o filename Write the trace output to the file filename rather than to stderr. Use filename.pid if -ff
is used. If the argument begins with `|’ or with `!’ then the rest of the argument is
treated as a command and all output is piped to it. This is convenient for piping the
debugging output to a program without affecting the redirections of executed programs.

Time stamps displayed with -tt option is not very useful in this example, but it is very useful while debugging application performance issues. -T which shows the time spend in each system call is also useful for those issues.

From strace output,

10:26:11.901173 socket(PF_INET, SOCK_DGRAM, IPPROTO_IP) = 3
10:26:11.901279 connect(3, {sa_family=AF_INET, sin_port=htons(123), sin_addr=inet_addr(“127.0.0.1″)}, 16) = 0
10:26:11.901413 getsockname(3, {sa_family=AF_INET, sin_port=htons(38673), sin_addr=inet_addr(“127.0.0.1″)}, [16]) = 0
10:26:11.901513 close(3) = 0
10:26:11.901621 socket(PF_INET6, SOCK_DGRAM, IPPROTO_IP) = 3
10:26:11.901722 connect(3, {sa_family=AF_INET6, sin6_port=htons(123), inet_pton(AF_INET6, “::1″, &sin6_addr), sin6_flowinfo=0, sin6_scope_id=0}, 28) = -1 ENETUNREACH (Network is unreachable) <—————-
10:26:11.901830 close(3) = 0
10:26:11.901933 socket(PF_INET, SOCK_DGRAM, IPPROTO_UDP) = 3
10:26:11.902033 connect(3, {sa_family=AF_INET, sin_port=htons(123), sin_addr=inet_addr(“127.0.0.1″)}, 16) = 0
10:26:11.902130 socket(PF_INET6, SOCK_DGRAM, IPPROTO_UDP) = 4
10:26:11.902238 connect(4, {sa_family=AF_INET6, sin6_port=htons(123), inet_pton(AF_INET6, “::1″, &sin6_addr), sin6_flowinfo=0, sin6_scope_id=0}, 28) = -1 ENETUNREACH (Network is unreachable) <—————-
10:26:11.902355 fstat(1, {st_dev=makedev(0, 11), st_ino=3, st_mode=S_IFCHR|0620, st_nlink=1, st_uid=528, st_gid=5, st_blksize=1024, st_blocks=0, st_rdev=makedev(136, 0), st_atime=2015/02/17-10:26:11, st_mtime=2015/02/17-10:26:11, st_ctime=2015/02/17-10:16:32}) = 0
10:26:11.902490 mmap(NULL, 4096, PROT_READ|PROT_WRITE, MAP_PRIVATE|MAP_ANONYMOUS, -1, 0) = 0x7fc5a8752000
10:26:11.902608 write(1, “can’t create socket connection”, 30) = 30

Let us have a deeper look,

You can see that socket() is opening a socket with PF_INET (IP v4) domain and IPPROTO_IP (tcp) protocol. This returns file descriptor 3. Then connect() is connecting to the socket using the same file descriptor and connects to ntp port (123) in localhost. Then it calls getsockname and closes the file descriptor for the socket.

10:26:11.901173 socket(PF_INET, SOCK_DGRAM, IPPROTO_IP) = 3
10:26:11.901279 connect(3, {sa_family=AF_INET, sin_port=htons(123), sin_addr=inet_addr(“127.0.0.1″)}, 16) = 0
10:26:11.901413 getsockname(3, {sa_family=AF_INET, sin_port=htons(38673), sin_addr=inet_addr(“127.0.0.1″)}, [16]) = 0
10:26:11.901513 close(3) = 0

Next it does the same but with PF_INET6 (IP v6) domain. But you can see that connect() fails with ENETUNREACH.

10:26:11.901621 socket(PF_INET6, SOCK_DGRAM, IPPROTO_IP) = 3
10:26:11.901722 connect(3, {sa_family=AF_INET6, sin6_port=htons(123), inet_pton(AF_INET6, “::1″, &sin6_addr), sin6_flowinfo=0, sin6_scope_id=0}, 28) = -1 ENETUNREACH (Network is unreachable) <—————-
10:26:11.901830 close(3)

From connect man page,

ENETUNREACH
Network is unreachable.

This process is repeated with IPPROTO_UDP (udp) protocol as well.

On checking the system, I see that that only IPv4 is enabled. ‘inet6 addr’ line is missing.

[root@pbsftp ~]# ifconfig
eth0 Link encap:Ethernet HWaddr 00:50:56:90:2E:31
inet addr:xx.xx.xx.xx Bcast:xx.xx.xx.xx Mask:xx.xx.xx.xx <——————–
UP BROADCAST RUNNING MULTICAST MTU:1500 Metric:1
RX packets:5494691 errors:0 dropped:0 overruns:0 frame:0
TX packets:4014672 errors:0 dropped:0 overruns:0 carrier:0
collisions:0 txqueuelen:1000
RX bytes:5877759230 (5.4 GiB) TX bytes:5608605924 (5.2 GiB)

IPv6 is disabled in the system using following /etc/sysctl.conf entries.

net.ipv6.conf.default.disable_ipv6=1
net.ipv6.conf.all.disable_ipv6 = 1

This behavior of nagios plugin is wrong as it should not die when one of the connect fails.

Issue is fixed in upstream patch.

Enabling IPv6 by removing following entries from /etc/sysctl.conf and running ‘sysctl -p’ would act as a workaround.

net.ipv6.conf.default.disable_ipv6=1
net.ipv6.conf.all.disable_ipv6 = 1

To fix the issue, the upstream patch need to be either backported manually to create an rpm or a support ticket need to be opened with the operating system vendor to backport the patch in their product release.

Categories: DBA Blogs

MySQL Sounds Like Fun

Mon, 2015-03-16 07:48

I love finding out new things about MySQL. Last week, I stumbled on a query that had the phrase “SOUNDS LIKE” in it. Sounds made-up, right? Turns out MySQL is using a known “soundex” algorithm common to most databases, and popular in use cases in geneaology.

The basic idea is that words are encoded according to their consonants. Consonants that sound similar (like M and N) are given the same code. Here’s a simple example:

(“soundex” and “sounds like” are different ways of doing the same thing in these queries)

MariaDB> select soundex("boom");
+-----------------+
| soundex("boom") |
+-----------------+
| B500            |
+-----------------+

MariaDB> select soundex("bam");
+----------------+
| soundex("bam") |
+----------------+
| B500           |
+----------------+

MariaDB> select soundex("bin");
+----------------+
| soundex("bin") |
+----------------+
| B500           |
+----------------+

This simple example isn’t terribly useful, but if you were trying to find similar, but differently spelled, names across continents, it could be helpful:

MariaDB> select soundex("William");
+--------------------+
| soundex("William") |
+--------------------+
| W450               |
+--------------------+

MariaDB> select soundex("Walaam");
+-------------------+
| soundex("Walaam") |
+-------------------+
| W450              |
+-------------------+

MariaDB> select soundex("Willem");
+-------------------+
| soundex("Willem") |
+-------------------+
| W450              |
+-------------------+

MariaDB> select soundex("Williama");
+---------------------+
| soundex("Williama") |
+---------------------+
| W450                |
+---------------------+

And you could probably agree these variations match as well:

MariaDB> select soundex("Guillaume");
+----------------------+
| soundex("Guillaume") |
+----------------------+
| G450                 |
+----------------------+

MariaDB> select soundex("Uilleam");
+--------------------+
| soundex("Uilleam") |
+--------------------+
| U450               |
+--------------------+

MariaDB> select soundex("Melhem");
+-------------------+
| soundex("Melhem") |
+-------------------+
| M450              |
+-------------------+

MariaDB> select soundex("Uilliam");
+--------------------+
| soundex("Uilliam") |
+--------------------+
| U450               |
+--------------------+

Well, that’s pretty neat. Of course, I want to try the silliest word I can think of:

MariaDB> select soundex("supercalifragilisticexpealidocious");
+-----------------------------------------------+
| soundex("supercalifragilisticexpealidocious") |
+-----------------------------------------------+
| S162416242321432                              |
+-----------------------------------------------+

So the algorithm doesn’t stop at 3 digits; good to know.

What does the algorithm do? Luckily MySQL is open source, and so we can look in the source code:

This looks like the raw mapping. And then this is called into a function that loops through the characters in the word.

/* ABCDEFGHIJKLMNOPQRSTUVWXYZ */
/* :::::::::::::::::::::::::: */
const char *soundex_map= "01230120022455012623010202";

Note that even though it’s called “sounds like” it is really simply a character mapping based on an agreement by the developers’ ears which characters sounds similar. That’s of course an oversimplification, and I see in the code comments the following:

/****************************************************************
* SOUNDEX ALGORITHM in C *
* *
* The basic Algorithm source is taken from EDN Nov. *
* 14, 1985 pg. 36. *

But despite hitting up several librarians, I can’t seem to get a copy of this. Someone out there has a copy sitting around, right?

As a side note, this is obviously specific to the English language. I found references to German and other languages having soundex mappings, and would be curious to see those and hear of any language-specific ways to do this.

Curiosity aside, here’s a real use.

I pulled down some government climate data. Let’s say the location field has some of my favorite misspellings of “Durham” in it:

MariaDB [weather]> select distinct(two), count(two) from weather.temps group by two;
+--------------------------------------------+------------+
| two                                        | count(two) |
+--------------------------------------------+------------+
| NULL                                       |          0 |
| DRM                                        |         51 |
| DURHAM                                     |    1101887 |
| DURM                                       |         71 |
| NCSU                                       |    1000000 |
| RALEIGH DURHAM INTERNATIONAL AIRPORT NC US |    1096195 |
| RDU AIRPORT                                |    1000000 |
+--------------------------------------------+------------+

A “LIKE” clause won’t work terribly well here.

I confirmed the misspellings would match as I expected:

MariaDB [weather]> select soundex("Durham"), soundex("Durm"), soundex("DRM");
+-------------------+-----------------+----------------+
| soundex("Durham") | soundex("Durm") | soundex("DRM") |
+-------------------+-----------------+----------------+
| D650              | D650            | D650           |
+-------------------+-----------------+----------------+

So instead of manually creating a query like:

MariaDB [weather]> select count(two) from weather.temps where two='DRM' or two='DURHAM' or two='DURM';
+------------+
| count(two) |
+------------+
|    1102009 |
+------------+

I can simply do this:

MariaDB [weather]> select count(two) from weather.temps where two sounds like 'Durham';
+------------+
| count(two) |
+------------+
|    1102009 |
+------------+

There are more than several ways to do string comparisons, but I enjoyed finding this one.

(Bonus points will be granted to the first person who comments that RDU is also Durham and submits a unique query to include it in the count.)

Categories: DBA Blogs

Monitoring Cassandra with Grafana and Influx DB

Mon, 2015-03-16 07:37

Hello,

In this post I will explain how to set up Cassandra monitoring with influxDB and Grafana. This can also be used to connect to other monitoring systems (Graphite, Collectd, etc…) but since both influxDB and Grafana are hot topics at the moment I decided to follow the trend! I was asked why I was doing this when a tool like OpsCenter is available, but sometimes you want to have all your systems reporting to a single dashboard. And if your dashboard is Grafana and your Backend is influxDB then you will learn how to connect Cassandra to it!

Assumptions:
– You are running a Linux system (This post is based on CentOS 7)
– You are using Cassandra 1.2+ (I’m using 2.1.3 in this case)

Prerequisites
  • Cassandra Installation
  • Graphite Metrics Jar
  • influxDB – http://influxdb.com/
  • Grafana – http://grafana.org/
  • Apache (Any webserver would do)
Installing and configure influxDB

This one is dead easy, once you have the package install it (rpm -i, dpkg -i). Start the service:

service influxdb start

Once the service is running, go to the configuration (/opt/influxdb/shared/config.toml) and edit the file so that under [input_plugins] it looks like this:

# Configure the graphite api
[input_plugins.graphite]
enabled = true
# address = "0.0.0.0" # If not set, is actually set to bind-address.
port = 2003
database = "cassandra-metrics" # store graphite data in this database
udp_enabled = true

Save the file, reload the service:

service influxdb reload

Now go to your browser localhost:8083, click connect (no credentials should be needed), and after you logged in, enter in a database name (use cassandra-metrics) and click Create (This should be your only option). Now you can click the database, and add an user to it (and make it admin). Now create another database, with name “grafana”, create an admin for that database also.
Now you are done with influxDB.

Installing Grafana

Grafana is a bit more tricky, since it is needed to configure a webserver also. Let’s assume apache is installed, and the home directory for www is /var/www/html.

So get the grafana package and extract it to /var/www/html. So the end result should be something like /var/www/html/grafana.

Now do the following:

cd /var/www/html/grafana
cp config.sample.js config.js

Now let’s configure the connection between influXDB and Grafana. Open for edit the new copied file config.js and edit it so it looks like this:

datasources: {
  influxdb: {
    type: 'influxdb',
    url: "http://localhost:8086/db/cassandra-metrics",
    username: 'admin',
    password: 'admin',
  },
  grafana: {
    type: 'influxdb',
    url: "http://localhost:8086/db/grafana",
    username: 'admin',
    password: 'admin',
    grafanaDB: true
  },
},

Now redirect your browser to localhost/grafana and you will have the Grafana default dashboard.

Preparing Cassandra

Now the final piece of the puzzle. Now we follow more or less the Cassandra guide that exists here, but we need to make some changes to make it more valuable (and allow multiple nodes to provide metrics).

So, first of all, put the metrics-graphite-2.2.0.jar in all the Cassandra nodes /lib directory.
Now create a yaml file with similar to the Datastax example, lets call it influx-reporting.yaml and store it on /conf directory. Now edit the file again so it looks like this:

graphite:
-
  period: 60
  timeunit: 'SECONDS'
  prefix: 'Node1'
  hosts:
  - host: 'localhost'
    port: 2003
  predicate:
    color: "white"
    useQualifiedName: true
    patterns:
    - ".*"

What did we change here, first we added a prefix field, this will allow us to identify the node that is providing the metrics. It must be different for every node, otherwise the metrics will overwrite/mix with each other. Then we decided to allow all patterns (“.*”), this means that Cassandra will push out all the metrics into influxDB. You can decide whether or not this is too much and just enable the metrics you want (find out more about it here).

Now edit the cassandra-env.sh so that it will read the yaml file to provide the metrics. Add the following line to the end of the file:

JVM_OPTS="$JVM_OPTS -Dcassandra.metricsReporterConfigFile=influx-reporting.yaml"

If all is done correctly, you can restart the Cassandra node (or nodes, but don’t do it all at the same time, 2min between each is recommended) and if the log file has the following message:

INFO [main] YYYY-MM-DD HH:MM:SS,SSS CassandraDaemon.java:353 - Trying to load metrics-reporter-config from file: inf
lux-reporting.yaml
INFO [main] YYYY-MM-DD HH:MM:SS,SSS GraphiteReporterConfig.java:68 - Enabling GraphiteReporter to localhost:2003

All is good!

Graphing!

Grafana is not that difficult to use, so once you start exploring a bit (And reading the documentation) you will find out doing nice graphs. This could be a long post only about graphing out, so I’m just go and post some images of the graphs I’m getting out of Grafana so that you can see how it can be powerful and help you on keeping your Cassandra Healthy.

Grafana_cassandra-test3 Grafana_cassandra-test2 Grafana_cassandra-test1
Categories: DBA Blogs

Cassandra 101 : Understanding What Cassandra Is

Mon, 2015-03-16 07:35

As some of you may know, in my current role at Pythian, I am tackling OSDB and currently Cassandra is on my radar. So one of the things I have been trying to do is learn what Cassandra is, so in this series, I’m going to share a bit of what I have been able to learn.

According to the whitepaper “Solving Big Data Challenges for Enterprise Application Performance Management” , Cassandra is a “distributed key value store developed at Facebook. It was designed to handle very large amounts of data spread out across many commodity servers while providing a highly available service without single point of failure allowing replication even across multiple data centers as well as for choosing between synchronous or asynchronous replication for each update.”

Cassandra, in layman’s terms, is a NoSQL database developed in JavaOne. One of Cassandra’s many benefits is that it’s an open source DB with deep developer support. It is also a fully distributed DB, meaning that there is no master DB, unlike Oracle or MySQL, so this allows this database to have no point of failure. It also touts being linearly scalable, meaning that if you have 2 nodes and a throughput of 100,000 transactions per second, and you added 2 more nodes, you would now get 200,000 transactions per second, and so forth.

2015-03-12_1145

Cassandra is based on 2 core technologies, Google’s Big Table and Amazon’s Dynamo, which Facebook uses to power their Inbox Search feature and released it as an open source project on Google Code and then incubated at Apache, and is nowadays a Top-Level-Project. Currently there exists 2 versions of Cassandra:

Since Cassandra is a distributed system, it follows the CAP Theorem, which is awesomely explained here, and it states that, in a distributed system, you can only have two out of the following three guarantees across a write/read pair:

  • Consistency.- A read is guaranteed to return the most recent write for a given client.
  • Availability.-A non-failing node will return a reasonable response within a reasonable amount of time (no error or timeout).
  • Partition Tolerance.-The system will continue to function when network partitions occur.

Also Cassandra is a BASE (Basically Available, Soft state, Eventually consistent) type system, not an ACID (Atomicity, Consistency, Isolation, Durability) type system, meaning that the system is optimistic and accepts that the database consistency will be in a state of flux, not like ACID which is pessimistic and it forces consistency at the end of every transaction.

Cassandra stores data according to the column family data model where:

  • Keyspace is the container for your application data, similar to a schema in a relational database. Keyspaces are used to group column families together. Typically, a cluster has one keyspace per application.It also defines the replication strategy and data objects belong to a single keyspace
  • Column Family is a set of  one,two or more individual rows with a similar structure
  • Row is a collection of sorted columns, it is the the smallest unit that stores related data in Cassandra, and any component of a Row can store data or metadata
    •  Row Key uniquely identifies a row in a column family

      •  Column key uniquely identifies a column value in a row
      •  Column value stores one value or a collection of values
keyspace

Also we need to understand the basic architecture of Cassandra, which has the following key structures:

  • Node is one Cassandra instance and is the basic infrastructure component in Cassandra. Cassandra assigns data to nodes in the cluster, each node is assigned a part of the database based on the Row Key. Usually corresponds to a host, but not necessarily, specially in Dev or Test environments.
  • Rack is a logical set of nodes
  • Data Center is a logical set of Racks, a data center can be a physical data center or virtual data center. Replication is set by data center
  • Cluster contains one or more data centers and is the full set of nodes which map to a single complete token ring
Cassandra_Arch

Conclusion

Hopefully this will help you understand the basic Cassandra concepts. In the next series, I will go over architecture concepts of what a Seed node is, the purpose of the Snitch and topologies, the Coordinator node, replication factors, etc

Note 1:

André Araújo, a great friend of mine and previous Pythianite, wrote about his first experience with Cassandra : My First Experience with Cassandra – Part 1

Note 2:

This post was originally published in my personal blog: rene-ace.com

Categories: DBA Blogs

Log Buffer #414, A Carnival of the Vanities for DBAs

Mon, 2015-03-16 07:22

This Log Buffer Edition picks the sea shells from Blogs across the seas of Oracle, SQL Server and MySQL and arrange them for you in this Edition. Enjoy.

Oracle:

12c Parallel Execution New Features: Concurrent UNION ALL

Visualizing Statspack Performance Data in SQL Developer

Optimizer statistics – Gathering Statistics and Histograms

Big Data Made Actionable with Omar TawaKol at SXSW

Mobile backend with REST services and JSON payload based on SOA Suite 12c

SQL Server:

Setting Different Colors for Connections in SSMS

Defusing Database Time Bombs: Avoiding the Need to Refactor Databases

This article shows a step by step tutorial to create a virtual machine in 15 min on Windows Azure.

What SQL Statements Are Currently Using The Transaction Logs?

SQL Server Random Sorted Result Set

MySQL:

Oracle Linux 7.1 and MySQL 5.6

MySQL Workbench 6.3.2 RC has been released

MariaDB CONNECT storage engine now offers access to JSON

Avoiding MySQL ERROR 1052 by prefixing column names in multi table queries

MySQL 5.7.6 DMR: Packages, Repos, Docker Images

Categories: DBA Blogs