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EXPLAIN ANALYZE may be lying to you
Álvaro Hernández May 26, 2020 10 min read

The Observer effect In physics, the observer effect is the theory that the mere observation of a phenomenon inevitably changes that phenomenon. This is often the result of instruments that, by necessity, alter the state of what they measure in some manner. Observer effect, Wikipedia (edit; this previously referred to the Uncertainty principle) In layman’s terms, what the Observer effect states is that by measuring a property of a system, you may be altering that system itself: your observation becomes a distorted version of the reality.

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JOINs the hard way: comparing MongoDB and Postgres
Álvaro Hernández Apr 6, 2020 1 min read

JOINs the hard way: comparing MongoDB and Postgres Dr. Michael Stonebraker and I have just published a new blog post on our series comparing MongoDB and Postgres. This second post compares JOINing data in MongoDB and Postgres, and follows on our previous post, “Schema Later” Considered Harmful. This new post analyzes how to structure data in both systems to model a classical employee-department data model. We analyze why the embedded model won’t work for the Mongo case, and why the reference model is brittle in this system.

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