hadoop unstructured data

Tags: table operations CLU SQL ROM Tilt sort complete Section Select sortFirst, the data to re-order 1.1, go to Heavy Distinct and GROUP by Try to avoid using distinct for weight, especially large table operations, using GROUP by instead -- Not recommended Select DISTINCT Key from a -- Recommended Select Key from Group by Key 1.2. Sorting optimization Only order by produces a globally ordered result, which can be sorted according to the actual sce

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(i) importing from a relational database to HDFs1. Keep the following parameters as Import.scriptImport--connectJdbc:mysql://192.168.1.14:3306/test--usernameRoot--password1234-M1--null-string‘‘--tableUser--columns"Id,username,age"--target-dir/user/root/sqoop_test--This directory cannot exist2. Execute Sqoop--options-file./import.script(ii) Import from HDFs to a relational database1. Keep the following parameters as Export.scriptExport--connectJdbc:mysql://192.168.1.14:3306/test--usernameRoot--pa