From: Carl Youngblood <carl@...>
Date: 2004-06-10T02:08:54+09:00
Subject: Re: [ANN] Active Record 0.8.3: Modules, mapping, and transactions

Kirk Haines wrote:

>On Wed, 9 Jun 2004 21:15:37 +0900, David Heinemeier Hansson wrote
>
>>* Fixed so transactions are ignored on MyISAM tables for MySQL
>>   (use InnoDB to get transactions)
>>    
>>
>
>David, I'm curious about this design decision.  I went the exact opposite 
>direction with transactions in Kansas.  Regardless of whether transactions 
>are implemented at the DBD layer or by the database, transactions are always 
>implemented at the object level.  I find it interesting that you went the 
>other way, and am curious about the reasoning behind it?
>
Another option worth considering is using LOCK TABLES for MyISAM 
tables.  MySQL's argument on this is that the MyISAM engine is about 3 
times faster than the transactional engines and for those times when you 
need more than one query to accomplish your goals, locking the tables 
doesn't cause you to incur a large performance penalty.  It still 
doesn't protect you from a server outage or something but otherwise it 
works pretty well.

I can imagine some scenarios where you might end up with inconsistent 
data if you don't lock tables before performing a series of queries.

Carl