Voice of the DBA

Author: way0utwest

NoSQL Complaints

I think that NoSQL databases are a really interesting set of technologies, however they aren’t necessarily a panacea for many problems, including scalability. There are likely some problem domains where a particular NoSQL technology might work better than an RDBMS, and perhaps some situations where many types of databases would work well.

I ran across a piece that looked at some of the complaints that companies have with NoSQL technologies. It’s a generic piece, perhaps too generic, since a graph database is not like a document database. However it does talk about the issues that companies see, such as performing analytic queries. While a row-based RDBMS isn’t ideal for these queries, often the platforms work very well for a wide variety of reporting requirements.

I do think some of the problems people have noted have to do with the maturity of the systems. There are a lack of references for how to run a high uptime NoSQL database, not many data models to review that may or may not work well, and relatively few administrative techniques to maintain these databases. The problem isn’t that NoSQL databases can’t meet your needs, or run quickly, or provide many 9s of uptime, but rather many enterprise professionals might not know how to find the information to accomplish these goals. That’s something easily solved across time.

Ultimately I think the NoSQL world has a lot of maturing to do, and we, as professionals and media, need to start to differentiate among the various flavors of databases. I am glad to start seeing articles and blogs refer to graph databases when they cover a product like Neo4j rather than writing NoSQL. Slowly I am seeing MongoDB referred to more often as a document database, not a NoSQL database. It’s good to start to separate technologies and not confuse one with another.

One thing in the piece I did notice is that it’s likely that we will see more platforms and products incorporate both RDBMS and non-RDBMS technologies together. We see that in SQL Server already with the addition of columnstore technologies in the last few versions and Polybase to SQL Server 2016. I expect we’ll also start to see some of the capabilities of DocumentDB added to SQL Server, along with, perhaps, graph based technologies in the future.

Steve Jones

The Voice of the DBA Podcast

Listen to the MP3 Audio ( 2.7MB) podcast or subscribe to the feed at iTunes and LibSyn.

November 30, 2015
Python Command Line Calls
There was a time I worked in a company any we lived in the command line. This was in the early 90s, prior to Windows v3.1 being released and we primarily used DOS on a Novell network.

We also had paper phone books on every desk for the 1,000+ people on the property. However, as you might guess, the phone books went out of date, and were only updated a couple times a year. We might get a new sheet, but mostly people learned to cross out a name and write a new extension in for the people they dealt with regularly.

However updates to the master list happened regularly, every few days. These were done in a small Lotus 1-2-3 file that an administrative assistant maintained. As a network person, I knew where this lived, and arranged a text export of this every night with a scheduled task.

Why text? Well, I’d come from a university where we had our phone details in a text file and would grep the file to find information. In DOS, I knew we could do the same thing with FIND. However, rather than write the find command with parameters, I put a batch file on our global share that called FIND with the parameters needed and the path to the phone book. I called this 411.bat. When I needed a phone number, I could type

411 “Andy Warren”

I’d get Andy’s name, location, and phone number back. It was a trivial piece of programming for me, but the rest of the network team, all non-programmers, were thrilled. I even added a /? check to return help information to the user.

With my playing with Python last week, I decided to do this for myself as well. I took my Python program to send tweets and changed it to send a tweet when the program was called, and to send the parameter as the tweet. The code looked like this::
```
import sys
import tweepy
def send_a_tweet(tweettext):
consumer_key = "X1GWqgKpPP4OuqWJZ7hw6"
consumer_secret = "QW3EkMHlyzF69AHn8DjyWyRG5CAQ0wjK9RqUZ2"
access_token = '146009-MqpeZFslj0VGgTSik1fq5klvJpqc1x6HAsiu'
access_token_secret = '8wIZlPbIqXtczc2LOsJgjMP3dCRRw5ajMvkjEspF'

auth = tweepy.OAuthHandler(consumer_key, consumer_secret)
auth.set_access_token(access_token, access_token_secret)

api = tweepy.API(auth)

api.update_status(status=tweettext)

if __name__ == '__main__':
send_a_tweet(sys.argv[1])
```
I placed this in a “\tools” folder that I have in my path. I also added a “tweet.cmd” file in this folder with this code:

python c:\tools\send_tweet.py %1

Since Python.exe is in my path as well, I can do this:

And I’ll see this on my timeline. I guess you’ll all be able to see this as well.

Why bother? Well, it was partially playing around. As I have been learning Python, I have mostly been playing in an IDE, solving small problems, but not really doing things useful. I also like the idea of command line tools, since I find them quick. Tweetdeck is big and bloated, and if I wanted to send a tweet from my desk, this is a quick way to do it. I could do a “readtweets” as well, and may.

However I also learned how to call Python programs with a command line, which is a good step to starting to build more useful programs that I can customize. This is also the start of me being able to schedule a program, and perhaps build more automation into my life with Python.

Mostly, however, it was just fun.
November 27, 2015
Test if a File Exists with Powershell
Another post for me that is simple and hopefully serves as an example for people trying to get blogging as#SQLNewBloggers.

Awhile back I wrote a PowerShell script (PoSh) to download the SQL Saturday XML files used for the Guidebook application. These contain a bunch of the information that I wanted to collect, transform, and keep around.

However the script wasn’t great. It basically looped a set number of times and re-downloaded the files. Not the more efficient solution, especially if I want this to run regularly.

One of the enhancements I wanted to make was check if the file exists, and if not, then download it. However, if it does exist, then I’ll skip the file. I know this means I don’t get updated files if schedules change, which is possible, but in that case, I can just delete the file from my desktop and go from there.

I made a quick search, and found a few links to the Test-Path cmdlet. Essentially you give this a file path and it returns true or false. Almost exactly what I need. This is what I added to my code:

if (Test-Path $DestinationFile) {

#do something

}

However I want to take action if the file doesn’t exist. In most languages, I’d add a ! in front to signify "not". However that doesn’t work in PoSh, just like > doesn’t mean greater than.

Another search showed me the -NOT operator. That’s what I need, but I can’t do this:

if (-NOT Test-Path $DestinationFile) {

#do something

}

Instead, I need to have a single expression for -NOT, which means more parenthesis. Not a big deal. I used this code:

if (-NOT (Test-Path $DestinationFile)) {

#do something

}

That worked great and now I only download the files I need. If I want to re-download (for newer events), I just delete those files and re-run the script.

SQLNewBlogger

This post came about when I started working on the script. It actually took longer to write this than find the solution, add it to code, and test it. That process was about 5 minutes.

This post took about 10 minutes to write. I also had a second post based on similar modifications to the script, so I’m did that in another 5 minutes.

References

A few of the links I used:
- Powershell: Test if File Exists – http://stevehardie.com/2013/04/powershell-check-if-file-exists/
- Using the Test-Path Cmdlet – https://technet.microsoft.com/en-us/library/ee177015.aspx
- Introduction to Windows PowerShell’s If -Not Logic – http://www.computerperformance.co.uk/powershell/powershell_if_not.htm
November 25, 2015
Just Say No

Just say no was a tagline from my youth. As I recall, it didn’t work well then, but I hope it will work better for a different audience and in a different context today. I was reading Brent Ozar’s note about one of the toughest things for consultants to do: saying no. While I certainly think this isn’t a problem for some people that can’t find work, I do think this is an issue, and one that isn’t just a problem for consultants.

I have worked with many people across my career, and one of the things that most of them have struggled with is saying no. Maybe it’s fear over being scolded (or worse) by a manager. Maybe it’s the simple desire to please others. Perhaps it’s because we simple are eternal optimists, and we think we can handle everything thrown at us. No matter what your reason, many people find the inability to say no plagues them throughout their careers.

I’ve learned to say no across the last decade. I probably say no to more things than I agree to accomplish. There are times that I worry about how much I decline to tackle things at work. However I have learned to deliver what I agree to, and deliver it well. I’ve learned that to do that, I can’t tackle every project, idea, or assignment. There are times I have to push back and refuse (politely) to do something.

It’s a luxury for sure. I have been successful in my career, and I’m not in a position where the loss of my job would wreck my life. However I also realize time is the most valuable resource I have at work. Time is also the most valuable resource I have in life, and I have to learn to balance my use of that resource to continue to be successful. Hopefully you learn that as well.

Steve Jones

The Voice of the DBA Podcast

Listen to the MP3 Audio ( 2.1MB) podcast or subscribe to the feed at iTunes and LibSyn.

November 25, 2015