java - Access dataBase using Apache-Spark-SQL -


hi i'm new learner apache spark using java this correct way or not? code working,but performance wise slow don't know 1 best approach access data every loop. 

dataset<row> javardd = sparksession.read().jdbc(database_url, "sample", properties);  javardd.todf().registertemptable("sample");   dataset<row> users = sparksession.sql("select distinct from_user sample ");  list<row> members = users.collectaslist();  (row row : members) {   dataset<row> userconversation = sparksession.sql("select description sample from_user ='"+ row.getdecimal(0) +"'");  userconversation.show();  }

try create set users , execute query 

sparksession.sql("select description sample from_user in usersset);

this way execute 1 query pay overhead needed db connection once.

another approach if run spark on hdfs , 1 time query use tool sqoop load sql table in hadoop , use data natively in spark.


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