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Namit Jain commented on HIVE-3784: ---------------------------------- >>> Does this rule out bucketed map-join or hive.optimize.bucketmapjoin will >>> continue to work? If it is the earlier, shouldn't fixing that be a blocker >>> of this? That will continue to work. >>> Also, does this rule out map join of multiple small tables in a single >>> map-only job? As discussed on HIVE-3652, giving map-join hints to a nested >>> join automatically converts it into a single map-join map. No. If the join key is the same, it will be a single MR job as today. With different join keys, it needs some work to merge into a single MR anyway - that work is independent of this change. As I said before, with this jira, everything that explicitly needs a map-join hint will continue to work as is. Whatever is being de-supported did not need a explicit mapjoin hint in the first place. > de-emphasize mapjoin hint > ------------------------- > > Key: HIVE-3784 > URL: https://issues.apache.org/jira/browse/HIVE-3784 > Project: Hive > Issue Type: Improvement > Components: Query Processor > Reporter: Namit Jain > Assignee: Namit Jain > Attachments: hive.3784.1.patch, hive.3784.2.patch, hive.3784.3.patch, > hive.3784.4.patch > > > hive.auto.convert.join has been around for a long time, and is pretty stable. > When mapjoin hint was created, the above parameter did not exist. > The only reason for the user to specify a mapjoin currently is if they want > it to be converted to a bucketed-mapjoin or a sort-merge bucketed mapjoin. > Eventually, that should also go away, but that may take some time to > stabilize. > There are many rules in SemanticAnalyzer to handle the following trees: > ReduceSink -> MapJoin > Union -> MapJoin > MapJoin -> MapJoin > This should not be supported anymore. In any of the above scenarios, the > user can get the mapjoin behavior by setting hive.auto.convert.join to true > and not specifying the hint. This will simplify the code a lot. > What does everyone think ? -- This message is automatically generated by JIRA. If you think it was sent incorrectly, please contact your JIRA administrators For more information on JIRA, see: http://www.atlassian.com/software/jira