Merge: Semijoin hints are dropped by the merge

create table target stored as orc as select ss_ticket_number, ss_item_sk, current_timestamp as `ts` from tpcds_bin_partitioned_orc_1000.store_sales;

create table source stored as orc as select sr_ticket_number, sr_item_sk, d_date from tpcds_bin_partitioned_orc_1000.store_returns join tpcds_bin_partitioned_orc_1000.date_dim where d_date_sk = sr_returned_date_sk;


merge /* +semi(T, sr_ticket_number, S, 10000) */ into target T using (select * from source where year(d_date) = 1998) S ON T.ss_ticket_number = S.sr_ticket_number and sr_item_sk = ss_item_sk 
when matched THEN UPDATE SET ts = current_timestamp
when not matched and sr_item_sk is not null and sr_ticket_number is not null THEN INSERT VALUES(S.sr_ticket_number, S.sr_item_sk, current_timestamp);

     todo: do we care to preserve comments in original SQL?