https://community.cloudera.com/t5/Support-Questions/What-is-Sort-Merge-Bucket-SMB-Join-in-Hive-When-it-is-used/m-p/123658#M86402 <P>I got below answer:</P><P>In SMB join in Hive, each mapper reads a bucket from the first table and the corresponding bucket from the second table and then a merge sort join is performed. Sort Merge Bucket (SMB) join in hive is mainly used as there is no limit on file or partition or table join. SMB join can best be used when the tables are large. In SMB join the columns are bucketed and sorted using the join columns. All tables should have the same number of buckets in SMB join.</P> Sat, 12 Mar 2016 18:04:18 GMT rushikeshdeshmu 2016-03-12T18:04:18Z https://community.cloudera.com/t5/Support-Questions/What-is-Sort-Merge-Bucket-SMB-Join-in-Hive-When-it-is-used/m-p/123655#M86399 <P>Hi,</P><P>Can anyone explain What is Sort Merge Bucket (SMB) Join in Hive? When it is used?</P> Sat, 12 Mar 2016 17:19:08 GMT https://community.cloudera.com/t5/Support-Questions/What-is-Sort-Merge-Bucket-SMB-Join-in-Hive-When-it-is-used/m-p/123655#M86399 rushikeshdeshmu 2016-03-12T17:19:08Z https://community.cloudera.com/t5/Support-Questions/What-is-Sort-Merge-Bucket-SMB-Join-in-Hive-When-it-is-used/m-p/123656#M86400 <P>please refer to Hive wiki <A href="https://cwiki.apache.org/confluence/display/Hive/LanguageManual+JoinOptimization" target="_blank">https://cwiki.apache.org/confluence/display/Hive/LanguageManual+JoinOptimization</A></P> Sat, 12 Mar 2016 17:45:15 GMT https://community.cloudera.com/t5/Support-Questions/What-is-Sort-Merge-Bucket-SMB-Join-in-Hive-When-it-is-used/m-p/123656#M86400 aervits 2016-03-12T17:45:15Z https://community.cloudera.com/t5/Support-Questions/What-is-Sort-Merge-Bucket-SMB-Join-in-Hive-When-it-is-used/m-p/123657#M86401 <P>@<A href="https://community.hortonworks.com/users/393/aervits.html">Artem Ervits</A>, thanks for reply and link.</P> Sat, 12 Mar 2016 18:01:02 GMT https://community.cloudera.com/t5/Support-Questions/What-is-Sort-Merge-Bucket-SMB-Join-in-Hive-When-it-is-used/m-p/123657#M86401 rushikeshdeshmu 2016-03-12T18:01:02Z https://community.cloudera.com/t5/Support-Questions/What-is-Sort-Merge-Bucket-SMB-Join-in-Hive-When-it-is-used/m-p/123658#M86402 <P>I got below answer:</P><P>In SMB join in Hive, each mapper reads a bucket from the first table and the corresponding bucket from the second table and then a merge sort join is performed. Sort Merge Bucket (SMB) join in hive is mainly used as there is no limit on file or partition or table join. SMB join can best be used when the tables are large. In SMB join the columns are bucketed and sorted using the join columns. All tables should have the same number of buckets in SMB join.</P> Sat, 12 Mar 2016 18:04:18 GMT https://community.cloudera.com/t5/Support-Questions/What-is-Sort-Merge-Bucket-SMB-Join-in-Hive-When-it-is-used/m-p/123658#M86402 rushikeshdeshmu 2016-03-12T18:04:18Z https://community.cloudera.com/t5/Support-Questions/What-is-Sort-Merge-Bucket-SMB-Join-in-Hive-When-it-is-used/m-p/123659#M86403 <P>@<A href="https://community.hortonworks.com/users/2769/rushikeshdeshmukh007.html">Rushikesh Deshmukh</A></P><P>What is the purpose of merging the tables used in joins ?? can you please explain??</P><P></P> Mon, 19 Sep 2016 12:00:05 GMT https://community.cloudera.com/t5/Support-Questions/What-is-Sort-Merge-Bucket-SMB-Join-in-Hive-When-it-is-used/m-p/123659#M86403 shivanageshch 2016-09-19T12:00:05Z https://community.cloudera.com/t5/Support-Questions/What-is-Sort-Merge-Bucket-SMB-Join-in-Hive-When-it-is-used/m-p/123660#M86404 <P>Does these configuration mentioned in this page work on TEZ engine .I could see SMB working only on MR</P> Fri, 09 Jun 2017 22:11:47 GMT https://community.cloudera.com/t5/Support-Questions/What-is-Sort-Merge-Bucket-SMB-Join-in-Hive-When-it-is-used/m-p/123660#M86404 viswanath_kammu 2017-06-09T22:11:47Z