Have you run explain for each query? If you look at the physical query plan it’s most likely the same. If the inner-query/join-table is small enough it should end up as a broadcast join.
From: Jayesh Lalwani <jayesh.lalw...@capitalone.com> Date: Wednesday, October 17, 2018 at 5:03 PM To: "user@spark.apache.org" <user@spark.apache.org> Subject: performance of IN clause Is there a significant differrence in how a IN clause performs when compared to a JOIN? Let's say I have 2 tables, A and B/ B has 50million rows and A has 1 million Will this query? Select * from A where join_key in (Select join_key from B) perform much worse than Select * from A INNER join on A.join_key = B.join_key Will the first query always trigger a broadcast of B? ________________________________ The information contained in this e-mail is confidential and/or proprietary to Capital One and/or its affiliates and may only be used solely in performance of work or services for Capital One. The information transmitted herewith is intended only for use by the individual or entity to which it is addressed. If the reader of this message is not the intended recipient, you are hereby notified that any review, retransmission, dissemination, distribution, copying or other use of, or taking of any action in reliance upon this information is strictly prohibited. If you have received this communication in error, please contact the sender and delete the material from your computer.
