PowerBI Report Builder query parameters

Hi v-easonf-msft 

    Thanks for your reply. I attached here screenshots of data source, data set and parameter properties below. When I run report in PowerBI Report Builder it let's me pass many customer_id values. Because it executes long time I ran the following queries on Oracle db using SQL Developer:

select sid, sql_id, serial#, osuser

from SYS.GV_$SESSION

where username = 'user  name used in Datasource connection';

and

SELECT SQL_FULLTEXT

FROM   SYS.GV_$SQL

WHERE  SQL_ID = '4vwzntwmagup9';

SQL_ID value is taken from result given by first query.  It gave me text of SQL statement actually being passed to and run by Oracle.  It's in this SQL statement I saw WHERE condition became 

WHERE cust_id IN (N'31341234134kwer', N'3898798734asf')

So parameter's values have been passed in national character set. This causes Oracle to convert cust_id column value to national character set before checking and so prevents it from using index based on cust_id.

Please let me know if you need any more details.

Best Regards,

gvinokur