Cassius Rosenthal on 6 Sep 2007 14:29:37 -0000

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Re: [PhillyOnRails] jruby + hadoop?

That's not quite fair, Toby. I agree that Casey was wrong to suggest
that RDBMs' text search hacks are adequate means to handle
unstructured data, but I didn't care for your response. Casey raised a
much larger issue that you did not address. I usually respect your
opinion (if not your demeanor,) but I was disappointed to see you give
in to resorting to straw-man argument instead of continuing (mostly)
reasoned discussion.
You're right. I apologize.

For the record, I take more offense from Kenosha's suggestion that RDBMS text searches are "hacks" inadequate for handling semi-structured data. I have recently uncovered inside information from an anonymous source suggesting that more than 97% of Aaron's current projects use RDBMSs for semi-structured data, and I would challenge him to justify deploying 'inadequate hacks' in his client's projects.


Seriously -- no offense taken.

The trick to understanding the state here is that its everywhere in a
traditional RDBMS, not just in the data. The schema and the query both
have state. The schema cannot be changed without big pain (the bigger the
data and the more tables, the more pain). As a result, the SQL queries
themselves than also carry state that limit their parallelizability. Plus,
the very power of SQL limits it in other ways, too.

OK -- I can see that changing schema (or a view) in an RBDMS requires an explicit command, and does not in CouchDB. So an RDBMS would return an error whereas CouchDB would just return nothing for that part of the graph. But BerkeleyDB is SQL-based. So does BerkeleyDBHA not require an explicit command to change shema?

I still think 'stateless' is the wrong word. Structured vs semi-structured seems a more reasonable distinction.

If you'd like a pretty good book on how SQL works under the hood and
the math behind it, check out The Art of SQL by Stephane Faroult.

Will do -- thanks for the suggestion.

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