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From Jan Lehnardt <>
Subject Re: [user] Re: The Blog
Date Mon, 09 Feb 2009 16:09:31 GMT

On 9 Feb 2009, at 16:56, Alan Bell wrote:

> selling airline tickets was always the classical problem you  
> couldn't do with Notes because you might overbook because of the  
> distributed system means no atomic updates and stock level checking.  
> That actually just shows how much older Notes is than the modern  
> airline where overbooking is standard policy. Anyhow an application  
> where there are multiple purchasers and a finite stock and the stock  
> levels must never ever be overcommitted probably gives the RDBMS an  
> advantage.

A single node CouchDB or a double-write (note, not
2-phase-commit) pair can handle this pretty well. It just
has limitations that true p2p setups don't have.


> Wout Mertens wrote:
>> On Feb 9, 2009, at 3:57 PM, Noah Slater wrote:
>>> On Mon, Feb 09, 2009 at 09:51:18AM -0500, Adam Petty wrote:
>>>> Could this thread be added to the wiki - with only minor editing  
>>>> for length
>>>> - maybe as "a RDBMS vs couch 'Discussion' ?"  or something  
>>>> similar?"...
>>> We've learnt from the book that such comparisons tend to be harmful.
>>> They lead people into thinking that there is a direct meaningful  
>>> comparison.
>>> Fundamentally, CouchDB and RDMS solve different problems.
>> I dunno, I think it would be interesting to compare the main  
>> benefits of each so that you know what the strong points of each are.
>> For example, suppose you implement schema-free in an RDBMS by  
>> adding a text field that contains a JSON string. You still keep  
>> some of the metadata, like _rev and _id, in proper fields.
>> However, thinking about that, it means you will need to re- 
>> implement everything CouchDB does, like views and replication.
>> To be honest, I think saying RDBMS and CouchDB are for different  
>> solutions is just you guys being nice. I think that any application  
>> would benefit from using the CouchDB model and only in very  
>> specific, very demanding cases an RDBMS would be better. I can't  
>> think of any examples though.
>> So here's my challenge to the mailing list, it's pretty much the  
>> same one that MrDonut posted: Give us an example of something that  
>> would be better be done with an RDBMS and something that would  
>> better be done with CouchDB.
>> I'll help you: I think it would be easier to create a wiki with  
>> CouchDB than with an RDBMS. It is possible in both but CouchDB just  
>> makes it easier. I suppose we'd have to ask the  
>> guys to know if that's true.
>> I don't know what would be done better in an RDBMS. Performance  
>> logging perhaps? Something with really stringent schema requirements?
>> Wout.

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