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Re:Cost-Based Optimizer in Apache Spark 2.2 by elvinyung on Thursday August 31, 2017 @03:11PM (#15142928)
On this topic, I really like the Join Order Benchmark paper: http://www.vldb.org/pvldb/vol9/p204-leis.pdf

It basically shows that most cost-based optimizers are pretty bad at cardinality estimation, which compounds when queries use more joins.

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