{"push_id":2925596601,"size":1,"distinct_size":1,"ref":"refs/heads/avoid-wild-guesses-in-estimates","head":"9ee7af5574724d7965adaa7d2bed7cccd1f8eb8b","before":"de53012d7327e9f0929ebfd0dbdf85489479c1cd","commits":[{"sha":"9ee7af5574724d7965adaa7d2bed7cccd1f8eb8b","author":{"name":"Andrii Rosa","email":"0dfa5100905c475f6ca556aa6238bcaabaf1f5ed@fb.com"},"message":"Avoid making wild guesses when estimating filters and joins\n\nIf the stats are missing, or it is simply not possible to give any reasonable\nestimate when all of the conjuncts are unsupported, return uknown estimate\ninstead of 0.9 filter factor.\n\nPreserve 0.9 filter factor for every additional conjunct when at least one\nconjunct can be reasonably estimated.\n\nThis change is supposed to protect from making wild guesses when estimating\nJOINs. Since the JOIN cardinality is estimated as cross_product * filter_factor.\nMaking wild guesses can result in completely unpredictable JOIN order, as one\nof the joins can be greatly overestimated.","distinct":true,"url":"https://api.github.com/repos/arhimondr/presto/commits/9ee7af5574724d7965adaa7d2bed7cccd1f8eb8b"}]}
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