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Jesus Camacho Rodriguez updated HIVE-11954: ------------------------------------------- Attachment: HIVE-11954.10.patch > Extend logic to choose side table in MapJoin Conversion algorithm > ----------------------------------------------------------------- > > Key: HIVE-11954 > URL: https://issues.apache.org/jira/browse/HIVE-11954 > Project: Hive > Issue Type: Bug > Components: Physical Optimizer > Affects Versions: 2.0.0 > Reporter: Jesus Camacho Rodriguez > Assignee: Jesus Camacho Rodriguez > Attachments: HIVE-11954.01.patch, HIVE-11954.02.patch, > HIVE-11954.03.patch, HIVE-11954.04.patch, HIVE-11954.05.patch, > HIVE-11954.06.patch, HIVE-11954.07.patch, HIVE-11954.08.patch, > HIVE-11954.09.patch, HIVE-11954.10.patch, HIVE-11954.patch, HIVE-11954.patch > > > Selection of side table (in memory/hash table) in MapJoin Conversion > algorithm needs to be more sophisticated. > In an N way Map Join, Hive should pick an input stream as side table (in > memory table) that has least cost in producing relation (like TS(FIL|Proj)*). > Cost based choice needs extended cost model; without return path its going to > be hard to do this. > For the time being we could employ a modified cost based algorithm for side > table selection. > New algorithm is described below: > 1. Identify the candidate set of inputs for side table (in memory/hash table) > from the inputs (based on conditional task size) > 2. For each of the input identify its cost, memory requirement. Cost is 1 for > each heavy weight relation op (Join, GB, PTF/Windowing, TF, etc.). Cost for > an input is the total no of heavy weight ops in its branch. > 3. Order set from #1 on cost & memory req (ascending order) > 4. Pick the first element from #3 as the side table. -- This message was sent by Atlassian JIRA (v6.3.4#6332)