[Web4lib] What Sort of Library is Open Source Software For?

[John Fereira]

At 04:05 PM 9/23/2005, John Creech wrote:
>On Fri, 23 Sep 2005, John Fereira wrote:
>
>>Whether a products beats the pants off another depends a lot on the 
>>requirements.  I know a lot of people that don't consider MySQL to 
>>be a viable technology for enterprise wide database driven 
>>applications, especially in the area of transaction management.
>
>Interesting.  NASA uses mySQL for mission critical apps, I seem to 
>remember.  I'll search that here in a minute.  I believe the Ames 
>Research Center moved from Oracle to mySQL in some areas degree 
>about 5 years ago:
>
>"MySQL Breaks Into the Data Center"
>http://www.computerworld.com/printthis/2003/0,4814,85900,00.html

I found this particular quote interesting:

Clark says switching NASA's application from Oracle was a breeze. "To 
switch to MySQL, we only had to install the MySQL database driver 
module and change the connect call to the database interface module," 
he explains. "Once this was done, we literally had to change 
approximately one line of code out of 15,000 lines to begin using 
MySQL in our first application."

If that's all they did then they were using the default database 
table types.  The default table type does not support 
transactions.  In other words, the commit and rollback calls are 
no-ops.  That leads me to believe that the application they were 
running didn't require transaction support.  For example, an 
application which required transaction support might perform several 
inserts/updates before commiting the transaction and it any of the 
insert/updates failed a rollback call can be made to undo the 
changes.  In a non-transactions safe database every insert/update 
would immediately be committed.  If an error occured during an 
insert/update the only way to fix it might be to try another update, 
which might not be possible if the first update failed do 
to  unavailable resources.  The result would be a corrupt database.


John Fereira
jaf30 at cornell.edu
Ithaca, NY