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MySQL does what? (Division by integers and 0)
Posted Thursday Sep 30th, 2010 12:08pm
by Joshua Drake
| Permalink

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I was sitting in #postgresql today (no not the twitter, the irc) talking to some of the community peeps and I came across this tidbit. MySQL casts integers to float before division[1]. Say what?

mysql> SELECT 3/5;
        -> 0.60
To be honest, I can't fault MySQL for this behavior. It falls in line with the MySQL mantra of make it easy, not "necessarily" correct. A division of 3/5 in a numeric or float would return 0.60. It makes the math easy and normal human consumable.

PostgreSQL and Python on the other hand would give you this:

postgres=# select 3/5;
 ?column? 
----------
        0
(1 row)

Python 2.6.5 (r265:79063, Apr 16 2010, 13:57:41) 
[GCC 4.4.3] on linux2
Type "help", "copyright", "credits" or "license" for more information.
>>> 3/5;
0
>>> 
To get the similar human consumable response you would want:
postgres=# select 3/5.0;
        ?column?        
------------------------
 0.60000000000000000000
(1 row)

Python 2.6.5 (r265:79063, Apr 16 2010, 13:57:41) 
[GCC 4.4.3] on linux2
Type "help", "copyright", "credits" or "license" for more information.
>>> 3/5.0;
0.59999999999999998
Python is using float versus numeric here which explains the disparity. However, MySQL does do something that violates a very basic, as in elementary school math mistake. MySQL defines division by zero as NULL. Yes, you read that correctly.

mysql> SELECT 102/(1-1);
        -> NULL
What should happen is:
postgres=# select 102/(1-1);
ERROR:  division by zero

>>> 102/(1-1);
Traceback (most recent call last):
  File "", line 1, in 
ZeroDivisionError: integer division or modulo by zero
That's correct, an ERROR or EXCEPTION 1. http://dev.mysql.com/doc/refman/5.0/en/arithmetic-functions.html#operator_divide 2. http://en.wikipedia.org/wiki/Division_by_zero

Categories: Business, OpenSource, PostgreSQL, Python, SQL

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PGXN: Are you a benefactor?
Posted Thursday Sep 30th, 2010 11:01am
by Joshua Drake
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O.k. so I have been pushing on everyone I know to support PGXN. Command Prompt, (you know, us) hadn't bothered to donate. Mainly we hadn't donated because we wanted to be a founding sponsor but just didn't have the budget for it, with the whole PostgreSQL Conference thing going on.

Today, we put our money where our rather obnoxious mouth is and became a benefactor (at the tune of 1k). So with that, step up people. Don't you want to be able to do this:

pgxn --install py-postgresql
Instead of downloading, compiling, finding missing dependencies, screwing around for an hour doing nothing but swearing at the fact that you don't have what you need to use Python + PostgreSQL? No. You don't want to do that. You want to donate to PGXN, so you don't have to.

Categories: Business, OpenSource, PostgreSQL, Python, SQL

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PgWest 2010: Talk Descriptions are up
Posted Thursday Sep 30th, 2010 10:17am
by Joshua Drake
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The talk descriptions for PgWest 2010 are now up. As you can see, there is a lot of content that will be presented over the three days. There is a great mix of developer and user (DBA) content. If you haven't done so already, now is the time to register.

Categories: Business, OpenSource, PostgreSQL, SQL

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PgWest, have you booked your room?
Posted Wednesday Sep 29th, 2010 02:17pm
by Joshua Drake
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If you have not booked your room for PgWest, now is the time. There is a very real possibility that the cost of the hotel will go up in the next week. Now is not the time to be a traditional geek procrastinator.

Categories: Business, OpenSource, PostgreSQL, SQL

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Oracle MySQL increasing support pricing
Posted Wednesday Sep 29th, 2010 10:58am
by Joshua Drake
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Oracle MySQL recently started sending letters to their current clients about upcoming price changes[1]. It is certainly expected that Oracle would increase pricing, but I wonder by how much?

Oracle owns another fairly well known Open Source database, BerkeleyDB. The pricing for BerkeleyDB. suggests that MySQL may be in for a culture shock. MySQL appears to have removed their support pricing from its website (a move that should not provide comfort to any customer) but as I recall (please correct me if I am wrong) it used to be anywhere from 2500.00 USD to 5000.00 USD, per installation. Whereas Oracle pricing is per processor. Oracle does give you a break if it is a multi-core machine but it isn't huge.

If we use the BerkeleyDB Transactional pricing as a model for what MySQL "could be" a quad core machine would cost a MySQL customer 11,600.00-23,200.00 per year. This is a guess because I don't know the calculation for a Xeon quad core, it would be somewhere between .25 and .75 per core. Oracle is not known for making their pricing clear.

Where am I going with all of this? It should be obvious, moving to PostgreSQL with support from a long standing, transparent support and pricing schedule can do nothing but benefit you in the future.

Updated: 09/29/2010 12:19: Current MySQL Pricing
1.
"Hello Customer,

I am writing as way of introduction.  My name is Juliet and I am your
MySQL contact at Oracle.  It is my understanding that you are the most
appropriate person to speak with at your organization regarding MySQL.
 If you have any MySQL requirements, questions on the products,
support, consulting or training we provide, please do not hesitate in
contacting me.

I'm sure you are aware that Oracle purchased Sun and therefore MySQL
last February.  We're being told that there will be changes to MYSQL's
pricing and possibly pricing model soon and wanted to let you know.
We have not had a price increase for over 6 years but there will be an
increase in the next price list that will be available soon.  We've
been expecting the increase for the past couple of months but I'm told
it the new price list will be released soon.

For those of you using Basic and Silver support we're being told those
options will no longer be available.  If you wish to continue with
Basic or Silver you will need to sign a multi-year agreement and you
would be able to keep using Basic or Silver for up to another 3 years.

If you are considering purchasing additional licenses for MySQL
support subscription, please let me know, because you can save money
if you do it before the changes take place, some time in the next
month or two.   You can also sign multi-year agreements and lock down
current prices for up to 3 years.

You can receive up to a 30% discount for a 3 yr. commitments pre-pay
but annual payments are available as well for multi-year agreements.

If you would like to speak to someone about MySQL Cluster, please let
me know and I can arrange for an expert to call you within the next
week.

Please let me know if you have any questions.


Categories: Business, OpenSource, PostgreSQL, SQL

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Break out your credit card, support #PGXN
Posted Tuesday Sep 28th, 2010 10:56am
by Joshua Drake
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PGXN is the stuff. It is going to enable a whole new ecosystem of software for PostgreSQL complete with easy install, easy search, modular design and yeah unfortunately Perl.

That said, it is time to pony up. David Wheeler has put in some serious effort, well thought out, professionally designed and peer reviewed effort on delivering a new architecture for PostgreSQL software and modules. He needs our financial support.

Go here and contribute, today. He is less than 7k away from his goal.


Categories: Business, OpenSource, PostgreSQL, Python, SQL

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Interviewed by Linux.com
Posted Thursday Sep 23rd, 2010 02:29pm
by Joshua Drake
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So, I broke down at purchased my Linux Foundation membership. Shortly thereafter I was requested to be interviewed. Here it is.

Categories: Business, OpenSource, PostgreSQL, Python, SQL

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PgWest 2010 Early Bird Registration Open!
Posted Wednesday Sep 15th, 2010 03:15pm
by Joshua Drake
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We are still finalizing the three days of content but the first tutorials of the conference have been accepted and early bird registration is now open.Tutorials:

  • Test Driven
  • Database Development
  • Building an Open Geospatial Analysis Technology Stack
  • Normalization Workshop
  • GUCs: a Three-Hour Tour
  • Django and PostgreSQL
Mini-tutorials:
  • PostgreSQL Backup and Recovery Methods
  • MVCC Unmasked
  • The PostgreSQL Query Planner
  • Writing C Functions and C User Defined Types on Windows Using Visual
  • Studio (C++)
  • Using the PostgreSQL System Catalogs
  • HTSQL NoSQL for PostgreSQL
  • Blue skies: Replication using Skytools and Londiste
  • Using LVM2 to provide copies of production data for testing

The PostgreSQL Conference provides an opportunity for the Postgres community to come together to share and celebrate the most recent advances to the product. If you are currently a Postgres user, or are considering deploying the world's most advanced open source database within your organization, you can't miss this show. This is a cost effective way to receive training, build your skills, hear from your peers and other end users about their implementations, and network with the community leaders to discuss future product directions. (And have some fun, too!)

Many thanks to our sponsors:

  • Founding: Command Prompt, Inc.
  • Diamond: EnterpriseDB
  • Gold: 2ndQuadrant
  • Silver: Enova Financial
  • Silver: PgExperts


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  • Is your PgWest 2010 presentation submitted?
    Posted Monday Sep 13th, 2010 11:54am
    by Joshua Drake
    | Permalink

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    One of the aspects of the Open Source community I love is the agile, on demand nature of getting things done. If a feature is missing, you can just add it and you can add it on demand, as you need it. If a bug is present, you can fix it yourself or pay someone else like CMD to fix it for you.

    Unlike other communities that are closed where requirements and demands can fester for years in an oblivion of "marketability".

    There is however a downside to this aspect of the Open Source community.

    We like to wait until the last minute.

    Well, now is the last minute!

    Get your talk in today and be part of the largest PostgreSQL Conference to date!


    Categories: Business, OpenSource, PostgreSQL, SQL

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    PgWest 2010, CFP about to close!
    Posted Tuesday Sep 7th, 2010 08:16am
    by Joshua Drake
    | Permalink

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    Yes, we said it was the 5th that the CFP would be closing but then we belatedly realized that a good portion of the United States would be having a BBQ and drinking whatever their favorite beverage is over the weekend. Thus in true PostgreSQL fashion, PgWest is missing its CFP release date but only for a week! That means, submit your paper, now.

    Categories: Business, OpenSource, PostgreSQL, SQL

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