Summer of Hope

the Mississippi River Valley

The true delight is in the finding out rather than in the knowing.
-- Isaac Asimov

Using Google's Blogsearch

I’m using hobix to power my blog. Unfortunately it requires some work to get the dynamic components up and running (search and comments).
So I decided to use Google’s Blogsearch which is pretty powerful.
To include a search box on your own site paste the following code into your HTML template and set the bl_url field to your own domain:

 <form method="get" action="http://blogsearch.google.com/blogsearch">
   <input name="as_q" size="15" maxlength="255" value="" type="text">
   <input name="sa" value="Google Search" type="submit">
   <input name="bl_url" value="blog.interlinked.org" type="hidden">
   <input name="ie" value="ISO-8859-15" type="hidden">
   <input name="oe" value="ISO-8859-15" type="hidden">
 </form>

The Blogsearch supports all standard operators from Google’s search, but also some blog-specific ones:

• inblogtitle: search only within the title of the blog
• inposttitle: search only within the title of the posting
• inpostauthor: search only within the author field
• blogurl: return only results starting with the given URL (that’s exactly what we use for our search-box)

The biggest advantage over Google’s Web-search is, that the Blogsearch almost instantly crawls your blog after you’ve pinged them, or a service monitored by Google.
I use two pinging-services:

• http://pingomatic.com/
• http://pingoat.com/index.php

Only a few seconds after the ping, my feed gets fetched from Google and my article is available via the Blogsearch.

The tools we use have a profound (and devious!) influence on our thinking habits, and, therefore, on our thinking.
— Edsger Dijkstra

posted in October 2006 on tutorials

Comments

Everything ever published on this site
Copyright 2005- by Michael Jakl, Austria

The true delight is in the finding out rather than in the knowing.
-- Isaac Asimov

The Most Amazing PostgreSQL Database

For me PostgreSQL is the most amazing (open source) database around. Even though, there is much interest in stripped down NoSQL databases like key-value stores or “data structure servers”, PostgreSQL continues to innovate at the SQL frontier.
In this post, I’ll show a few of the newer, less known, features of PostgreSQL- far beyond standard SQL.

hstore

hstore is a key-value store for simple data types. Using hstore, we’re able to create a key-value store within columns of a table.
To enable the hstore extension, run create extension hstore' in the PostgreSQL prompt. After that the hstore data type is available for our table definitions.
Let’s create a simple table with a hstore column:

create table hstoretest ( id serial primary key, data hstore );

To insert a few rows, we use a special syntax:

insert into hstoretest (data) values ('key1 => 123, key2 => "text"'::hstore);

Query the table as usual:

select * from hstoretest;

 id |                           data
----+-----------------------------------------------------------
  1 | "key1"=>"123", "key2"=>"text"

The hstore extension provides a lot of operators and functions to work with hstore columns, for example, selecting all key2 values:

select data -> 'key2' as key2 from hstoretest;

 key2
------
 text
(1 row)

Some more examples can be found here.

JSON

A JSON data type was introduced in release 9.2. Currently this is nothing more than a validating data type, thus it checks if the string we put into that column is a valid JSON object.
Let’s create a new table to play around with this type:

create table jsontest ( id serial primary key, data json );

Now let’s insert an invalid row:

insert into jsontest (data) values ('{"title":wrong}');

ERROR:  invalid input syntax for type json
LINE 1: insert into jsontest (data) values ('{"title":wrong}');
                                            ^
DETAIL:  Token "wrong" is invalid.
CONTEXT:  JSON data, line 1: {"title":wrong...

And now with the correct JSON syntax:

insert into jsontest (data) values ('{"title":"right"}');

There isn’t really much more to the JSON data type besides the ability to return rows of non-JSON tables as JSON:

select row_to_json(hstoretest) from hstoretest;

                                       row_to_json
-----------------------------------------------------------------------------------------
 {"id":1,"data":"\"key1\"=>\"123\", \"key2\"=>\"text\""}
(1 row)

Nice if you’re used to work with JSON object (in Web applications for example).

PLv8

Working directly with JSON and JavaScript has been all the rage in many of the NoSQL databases. Using the PLv8 extension, we can use JavaScript (executed by Google’s awesome V8 engine) directly in PostgreSQL. Together with the JSON data type, this offers amazing new possibilities.
Currently PLv8 isn’t included in the standard distribution of PostgreSQL (9.2), but installing it isn’t very hard, the only dependencies are postgresql and the v8 engine. Some distributions already have v8 in their repositories (Archlinux).
Compiling and installing the extension is straight forward as soon as the dependencies are in place:

make && sudo make install

No we can enable the plv8 extension within our database (as we did with hstore):

create extension plv8;

A particular nice example of using JSON and PLv8 comes from Andrew Dunstan:

create or replace function jmember (j json, key text )
 RETURNS text
 LANGUAGE plv8
 IMMUTABLE
AS $function$
  var ej = JSON.parse(j);
  if (typeof ej != 'object')
        return NULL;
  return JSON.stringify(ej[key]);
$function$;

The jmember function allows us to parse and read the JSON string and returns the member identified by key:

select jmember(data, 'title') from jsontest;

     jmember
-----------------
 "right"
(1 row)

Andrew also shows how to build an index to speed up access times in his post.

k-Nearest Neighbors

In PostgreSQL 9.1, a nearest neighbor indexing was introduced. This allows us to perform orderings etc. by a distance metric.
For example, I’ve downloaded the ispell spelling dictionaries, and loaded them into a tablewords like this:

create table words (word varchar(50) primary key);
copy words from 'english.0';

This inserts roughly 50000 words into the table.
Since we’re working with text data, let’s introduce another extensionpg_trgm, which builds tri-grams of strings (triples of three characters). Using theses tri-grams, we can compute a distance metric. Enable the extension like this:

create extension pg_trgm;

A tri-gram of hello would look like this:

select show_trgm('hello');
            show_trgm
---------------------------------
 {"  h"," he",ell,hel,llo,"lo "}
(1 row)

The distance metric is very simple, the more of these tri-grams match, the closer two strings are.
To take advantage of the nearest neighbor index, we have to build it:

create index word_trgm_idx on words using gist (word gist_trgm_ops);

Using the index we can query our table for a word, and return a list of most similar terms as well:

select word, word <-> 'hello' as distance from words order by word <-> 'hello' asc limit 10;
  word  | distance
--------+----------
 hello  |        0
 hellos |    0.375
 hell   | 0.428571
 hells  |      0.5
 heller | 0.555556
 hell's | 0.555556
 help   |    0.625
 helm   |    0.625
 held   |    0.625
 helps  | 0.666667
(10 rows)

The <-> operator comes from the pg_trgm extension, of course we could use simpler distances like numerical difference or geometric distance, but working with textual data is often perceived as particularly difficult (not so with PostgreSQL).

Now Postgres is more or less the first choice of people with experience running production databases. It’s more powerful, more reliable, and has a better set of features than any other open source data storage layer out there today.
— Peter van Hardenberg, Tech Lead, Heroku Postgres

posted in October 2012 on tutorials

Git Overview

My version control journey started with CVS, after that I looked at SVN, but never really used it. The shortcomings of centralized repositories were too obvious and with my increasing interest in Haskell I jumped on the distributed version control train with Darcs. I really, really liked it, but it had some nasty things too. After a while I was looking for something different and stumbled over Mercurial, again I was really happy with it but somehow my journey wasn’t over yet.
Continue to full post...

posted in August 2008 on tutorials

Mercurial Version Control Status in the ZSH Command Line Prompt

Show the status of the current project on the prompt.

I sometimes forget to push or pull changes to or from a remote repository. To remedy the problem I wrote myself a little script to show me the status on the prompt.
Continue to full post...

posted in August 2008 on tutorials

Emacs Basics

A very basic Emacs introduction.

It’s been a while since I wrote my Vim Introduction and Tutorial (exactly one year). A lot happened between now and then, I chose to get a better feeling about Emacs for example.
The reasons aren’t easily explained; The most prominent reason is the awesome AucTex-mode since I’m working heavily with LaTeX lately.
Anyways, learning Vim and Emacs is better than learning only one of them :-).
Continue to full post...

posted in February 2008 on tutorials

Addendum to "Time Machine for every Unix out there"

My article about using rsync to mimic the behavior of Apple’s Time Machine generated a lot of traffic, and more important, a lot of feedback.
In this article I’ll summarize and try to clarify a few things.
Continue to full post...

posted in December 2007 on tutorials

Time Machine for every Unix out there

Using rsync to mimic the behavior of Apple's Time Machine feature

rsync is one of the tools that have gradually infiltrated my day to day tool-box (aside Vim and Zsh).
Using rsync it’s very easy to mimic Mac OS X new feature called Time Machine. In this article I’ll show how to do it, but there is still a nice GUI missing – for those who like it shiny.
Continue to full post...

posted in November 2007 on tutorials

Linux peripheral devices configuration

Configuring "advanced" peripherals (Microsoft Ergonomic Keyboard 4000, Logitech MX1000) and performance tuning by installing the right display driver.

This weekend I tried to get my new keyboard (Microsoft Ergonomic Keyboard 4000) and my Logitech MX1000 Laser mouse to work properly. The Keyboard has many extra-keys I didn’t bother to count, and the mouse has 12 buttons which can be very useful at times.
Almost accidently I solved a bugging performance problem with the Firefox browser. It was incredibly slow when opening Google Spreadsheets, well the whole system was incredibly slow while loading the spreadsheet… .
Continue to full post...

posted in September 2007 on tutorials

Vim Introduction and Tutorial

I often tried to learn the great Emacs editor/IDE/operating system. The last time I tried it, I spent some time getting comfortable with it until I wanted to customize my .emacs file.
That was the point when I entered vi .emacs. As soon as I realized what I’ve done, I knew that Vim has won me over a long time ago.
Continue to full post...

posted in February 2007 on tutorials

Haskell - Laziness

Haskell is a non-strict, or lazy, language. This means it evaluates expressions only when it needs their results.
Laziness is one of the things that make Haskell special – really special. Lazy evaluation allows easy handling of infinite data-structures.
Continue to full post...

posted in January 2007 on tutorials

Haskell Basics

The article I wrote yesterday was just the beginning, today we’ll look at the next step in becoming Haskell experts.
Yesterday we’ve learned how to split up our program and how to compile, or run it. Today we’ll look at some basic features of Haskell.
Continue to full post...

posted in January 2007 on tutorials

Haskell

Danger! If you are happy with your current knowledge of programming languages, don’t read on – Haskell might be responsible for some serious defects in your motivation.
I was always some kind of programming language geek. I loved learning and playing around with all kinds of programming languages¹. Currently I’m trying to learn Haskell. Even though I learned functional programming at my university (two semesters using Haskell), I didn’t really learn how to interact with the outside world. This is where things start to get messy, no matter how beautiful the language is.
Continue to full post...

posted in January 2007 on tutorials

Using Google's Blogsearch

I’m using hobix to power my blog. Unfortunately it requires some work to get the dynamic components up and running (search and comments).
So I decided to use Google’s Blogsearch which is pretty powerful.
Continue to full post...

posted in October 2006 on tutorials

Darcs

Taking version control to the next level.

Common version control tasks, and how they’re done using Darcs, a fresh approach to version control.
Continue to full post...

posted in August 2006 on tutorials

Installing SQLite, Lighttpd, FastCGI and Ruby bindings on Mac OS X

I’ve had a hard time installing SQLite, Lighttpd, FastCGI together with Ruby bindings on OS X, so I thought I could share my experiences.
Continue to full post...

posted in February 2006 on tutorials

Everything ever published on this site
Copyright 2005- by Michael Jakl, Austria

+Ronald





















 
















 




21

Share

Screen reader users, click here to turn off Google Instant.

Web

Images

Maps

News

VideosMore

 

 

 

Search tools

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

About 73,300,000 results (0.68 seconds)

Search Results

Mississippi

www.mississippi.gov/


 


 


 


 
Mississippi
Starting with the June 3, 2014 Primary Election, all Mississippians voting at the polls will be required to show a photo id.Learn more about the Mississippi Voter ...

Mississippi - Wikipedia, the free encyclopedia

en.wikipedia.org/wiki/Mississippi


 


 


 


 
Wikipedia
Mississippi
is bordered on the north by Tennessee, on the east by Alabama, on the south by Louisiana and a narrow coast on the Gulf of Mexico and on the west ...
‎Mississippi River - ‎Jackson, Mississippi - ‎List of US states by income - ‎Phil Bryant

Visit Mississippi

www.visitmississippi.org/


 


 


 


 
Your official source for Mississippi tourism and travel. Find things to do in Mississippi, Mississippi travel guide, Mississippi events, Mississippi hotels, Mississippi ...

---



1. News for mississippi


Politico
1. TV ad war ramps up in Mississippi Senate runoff (VIDEO)
Washington Post (blog)
‎- 32 minutes ago
With less than two weeks to go until the Republican runoff for U.S. Senate in Mississippi, the television battle over the airwaves is ramping back ...
2. Protests aim at Mississippi's New York picnic
Wall Street Journal
‎ - 1 day ago
3. Can the media avoid a freak-show tone?
The Atlantic
‎ - by James Fallows‎ - 4 days ago

More news for mississippi

---




Mississippi Development Authority | Mississippi: The Best ...

www.mississippi.org/


 


 


 


 
Mississippi
Development Authority is the leading Economic Development Agency for the State of Mississippi, assisting site selectors and businesses looking to ...

---



2. Images for mississippiReport images




 



 




 



 




 
More images for mississippi

---




Mississippi - Infoplease

www.infoplease.com › United States › States


 


 


 


 
Information on Mississippi — economy, government, culture, state map and flag, major cities, points of interest, famous residents, state motto, symbols, ...

Mississippi College | A Christian University

www.mc.edu/


 


 


 


 
Mississippi College
Mississippi
College, affiliated with the Mississippi Baptist Convention, is a private, co-educational, Christian university of liberal arts and sciences.

404 - Mississippi

www.ms.gov/pages/portalhome.aspx


 


 


 
MS.gov
The Official Web Site of the State of Mississippi. ... More Contact Resources. Skip Navigation Links ms.gov | The Official website of the State of Mississippi > 404 ...

Mississippi State Legislature

www.legislature.ms.gov/


 


 


 


 
Mississippi
Legislature. Legislators ... The Legislature. The Mississippi Legislature is not in session. ​ ... Learn more about Mississippi's Lieutenant Governor.

Mississippi State University

www.msstate.edu/


 


 


 


 
Mississippi State University
A land-grant university offering degrees through the doctoral level, Mississippi State University is the largest university in the state.

---



6. In-depth articles

What Can Mississippi Learn From Iran?

The New York Times
-
Jul 2012Nowhere is our health care system more broken and desperate than rural Mississippi. Can an approach used in Iran help save lives?

The Fifth Circuit turns its back on a huge forensics ...

The Washington Post
-
Feb 2014With a curt, three-page ruling late last month, a three-judge panel from the U.S. Court of Appeals for the Fifth Circuit denied the post-conviction petition of Tavares Flaggs, a Mississippi ...

Mississippi Abortion Clinic Law Set To Take Effect

huffingtonpost.com

-

Jun 2012JACKSON, Miss. -- Mississippi could soon become the only state without an abortion clinic because of a new law taking effect this weekend. Critics say the law would force women to ...

Explore: clinic

---

Searches related to mississippi

mississippi cities

mississippi facts

mississippi burning

mississippi state university

mississippi studios

mississippi state football

mississippi elections

mississippi abbreviation

---

1

2

3

4

5

6

7

8

9

10

Next

1. Mississippi
US State
2. Mississippi is a U.S. state located in the Southern United States. Jackson is the state capital and largest city with 175,437 people in 2012 up 1.1% from the 2010 U.S. Census with 173,514. Wikipedia
3. Capital: Jackson
4. Governor: Phil Bryant
5. Motto: Seal of Mississippi
6. Rivers: Mississippi River, Tennessee River, Yazoo River,
34. More
35. Colleges and Universities: University of Mississippi,
84. More
85. Destinations
View 45+ more



Jackson




Natchez




Biloxi



Gulfport




Vicksburg
86. Points of interest

View 45+ more

Vicksburg National Military P...

Mississippi Museum of Natural S...

Jackson Zoo

Old Mississippi State Cap...

USS Cairo

Feedback

Lackawanna, Jacksonville, FL - From your Internet address - Use precise location

- Learn more

Help Send feedback Privacy & Terms

Mississippi River System

From Wikipedia, the free encyclopedia

Jump to: navigation, search

Map of the course, watershed, and major tributaries of the Mississippi River

The Mississippi River System, also referred to as the Western Rivers, is a mostly riverine network which includes the Mississippi River and connecting waterways.
From the perspective of natural geography and hydrology, the system consists of the Mississippi River itself and its numerous natural tributaries and distributaries. The major tributaries are the Ohio, Illinois, Arkansas, Red and Missouri Rivers and, indirectly, such major Ohio River tributaries as the Allegheny, Tennessee, and Wabash rivers. ^[1]
From the perspective of modern commercial navigation, the system includes the above as well as navigable inland waterways which are connected by artificial means. Important connecting waterways include the Illinois Waterway, the Tennessee-Tombigbee Waterway, and the Gulf Intracoastal Waterway. This system of waterways is maintained by the U.S. Army Corps of Engineers with a project depth of between 9 and 12 feet (2.7 – 3.7 m) to accommodate barge transportation, primarily of bulk commodities. ^[2]
The Mississippi River carries 60% of U.S grain shipments, 22% of oil and gas shipments, and 20% of coal.^[3]

Notes[edit]

1. Jump up ^ "Mississippi River". USGS Biological Resources. Archived from the original on 2005-10-28. Retrieved 2006-03-08.
2. Jump up ^ "The Mississippi River System". US Army Corps of Engineers. Retrieved 2006-03-08.
3. Jump up ^ http://www.npr.org/2013/01/10/168950808/mississippi-blues-when-the-river-doesnt-run

---

This article about a specific United States location is a stub. You can help Wikipedia by expanding it. v t e

Coordinates: 47°14′23″N 95°12′27″W / 47.23972°N 95.20750°W / 47.23972; -95.20750

Retrieved from "http://en.wikipedia.org/w/index.php?title=Mississippi_River_System&oldid=597452471"

Categories:

• United States geography stubs
• Mississippi River
• Mississippi embayment
• Waterways in the United States

Hidden categories:

• Coordinates on Wikidata

Navigation menu

Personal tools

• Thunderlane125
• 1
• Talk
• Sandbox
• Preferences
• Beta
• Watchlist
• Contributions
• Log out

Namespaces

• Article
• Talk

Variants

Views

• Read
• Edit
• View history
• Watch

More

Search

Navigation

• Main page
• Contents
• Featured content
• Current events
• Random article
• Donate to Wikipedia
• Wikimedia Shop

Interaction

• Help
• About Wikipedia
• Community portal
• Recent changes
• Contact page

Tools

• What links here
• Related changes
• Upload file
• Special pages
• Permanent link
• Page information
• Data item
• Cite this page

Print/export

• Create a book
• Download as PDF
• Printable version

Languages

Edit links

• This page was last modified on 28 February 2014 at 00:23.
• Text is available under the Creative Commons Attribution-ShareAlike License; additional terms may apply. By using this site, you agree to the Terms of Use and Privacy Policy. Wikipedia® is a registered trademark of the Wikimedia Foundation, Inc., a non-profit organization.

• Privacy policy
• About Wikipedia
• Disclaimers
• Contact Wikipedia
• Developers
• Mobile view

• 
•