RewriteLogic

Input Query:

~/Desktop/rambo/presto --server localhost:8082 --catalog hive --schema default --execute "Select * from userdb.table2 ";

First code checks whether its case of impersonation and if it is then if the user is truster user

Need API here


DBSTableKeeper is called

-------

private static final String TABLE_NAME_PREFIX = "__DBS_t";
   private static final Pattern UNION_SPLIT_PATTERN = Pattern.compile("(?i)UNION");
   private static final Pattern GENERATED_VIEW_PATTERN = Pattern.compile("(?i)select[\\s]+DBS[\\s]+from[\\s]+__DBS_t[0-9]+");

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It calls DBSRowFilterColumnMaskRewrite

we get query :
SELECT * FROM   (    SELECT DBS    FROM      __DBS_t1 )  table2

which is replaced to :

var 20 is hardcode to APS (there is connection to policy iengine and query is sent to PE)

SELECT * FROM   (    APS )  table2




query re-wrote to