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 Teradata : Logic for Hash function (hashrow and hashbucket) Problem statement This is regarding on knowing the mathematics(logic) behind the hash function (hashrow and hashbucket) in Teradata side Teradata SQL : By debaditc, 25 Aug 2015 | Tagged: hashrow Hive hash code String limit for checksum calculation using HASH_MD5 function Hi Experts,   We are using HASH_MD5 function to calculate the checksum of columns in a table by concatinating them. hash_md5(col1||col2||col3||.......||col32). This function returns distinct value till certain column limit but any further column addition does not have any impact on checksum calculation.  , 11 Aug 2015 | 1 comment Redistribution to all AMPs Hi, everyone! As I have understood, generally, when performing a query the result goes to the Spool which can be 1. built locally on the AMP 2. duplicated to all AMPs 3. redistributed by hash code to all AMPs Could you tell me, how the Optimizer decides by which field the result is redistributed to all AMPs? Let's assume I have two tables T1 (fields p1, p2), T2 (fields q1,q2,q3) and a query like this: SELECT T1.p2, T2.q2, T2.q3 FROM T1 INNER JOIN T2 ON (T1.p1=T2.q1) The result contains fields p2,q2,q3. So, by which field it will be redistributed to all AMPs? , 04 Jul 2011 | Tagged: all amps hash code | 3 comments