[aida] Image as a database (was Re: About observee)

Janko Mivšek janko.mivsek at eranova.si
Tue Jun 5 11:40:42 CEST 2007

Hi Stefan,

Stefan Schmiedl wrote:
>>>> Especialy the 'no sql' part. ;-)
>>> Which "no sql" part are you referring to?
> Oh, *that* part :-)
> I'm curious what I will do the next time I really have to use a
> database ... which will be sometime during this weekend :-)

Have you already considered a Smalltalk image as a database?

Smalltalk image contains live objects too besides to compiled code. And 
those live objects can be your app data. You can snapshot (save) an 
image from time to time to save your "database".

I'm actually using this technique for all my recent web apps. On my 
collocated server there is 20+ sites running in a single image, which 
has currently 368MB and is snapshotted every hour. This takes about 3-5s 
which hardly anyone notice.

Question arise: is such database safe? What if your image crash in the 
middle of a hour between snapshots?

This could be a problem is image would crash frequently. But from 
experience so far a VW  is very stable and above mentioned image is 
running for months without stop and it never crashed so far. Even if it 
will, we loose only one hour of data, which is acceptable for all but 
very specific apps.

So, I recommend you to reconsider your image as a sole database and 
you'll be suprised and ask yourself why you didn't come to that idea 
before :)

Best regards

Janko Mivšek
Smalltalk Web Application Server

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