Paul Rogers created IMPALA-8263: ----------------------------------- Summary: Planner failed to flip build/probe side of join Key: IMPALA-8263 URL: https://issues.apache.org/jira/browse/IMPALA-8263 Project: IMPALA Issue Type: Bug Components: Frontend Affects Versions: Impala 3.1.0 Reporter: Paul Rogers Assignee: Paul Rogers
TPC-H query 8 was reviewed after applying the changes proposed for DRILL-8014. (See {{tpch-all.test}}.) The revised plan has better cardinality number, but contains this odd structure: {noformat} 11:HASH JOIN [INNER JOIN] | hash predicates: o_custkey = c_custkey | row-size=139B cardinality=39.66K | |--04:SCAN HDFS [tpch.customer] | row-size=10B cardinality=150.00K | 10:HASH JOIN [INNER JOIN] | hash predicates: o_orderkey = l_orderkey | row-size=129B cardinality=39.66K {noformat} As I understand it, the planner should flip the left and right sides of an inner join if the right side (the 04 scan) has a larger cardinality than the left (join 10) side. That flip did not happen in this case, causing the join to build a hash table about 4 times larger than necessary. Perhaps there is some other constraint. Investigate to determine if the behavior is correct (and if so why), or the source of incorrect behavior. -- This message was sent by Atlassian JIRA (v7.6.3#76005) --------------------------------------------------------------------- To unsubscribe, e-mail: issues-all-unsubscr...@impala.apache.org For additional commands, e-mail: issues-all-h...@impala.apache.org