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SQL, Homomorphisms and Constraint Satisfaction Problems

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128 points xlinux | 2 comments | 20 Nov 24 17:07 UTC | HN request time: 0s | source
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lovasoa ◴[20 Nov 24 19:56 UTC] No.42197498[source]▶
The topic of huge queries on tiny databases makes me think of this recent discussion on the SQLite forum: https://sqlite.org/forum/forumpost/0d18320369

Someone had an issue because SQLite failed to optimize the following query

    select * from t where x = 'x' or '' = 'x'
Someone said that SQLite could not optimize out the "or '' = 'x'" because it would be too expensive to compute. Which is obviously true only for huge queries on tiny datasets.
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1. jiggawatts ◴[20 Nov 24 21:30 UTC] No.42198312[source]▶
> SQLite

Well... there's your problem. SQLite is not a general-purpose RDBMS, it is marketed as a replacement for "fopen()", a purpose for which it excels.

A similar product is the Microsoft Jet database engine, used in products such as Microsoft Exchange and Active Directory. Queries have to be more-or-less manually optimised by the developer, but they run faster and more consistently than they would with a general-purpose query engine designed for ad-hoc queries.

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2. cerved ◴[21 Nov 24 01:08 UTC] No.42199975[source]▶
I hate Jet with a vengeance