dplyr::rows_upsert (in_place=TRUE) with ROracle connection fails because dbplyr::sql_query_upsert.OraConnnection puts a semicolon at the end of the query. Without that semicolon the query works just as expected.
dplyr::rows_update with OraConnection produces "update from " query that is not supported by Oracle.
This is most likely due to fact that there is no sql_query_update.OraConnection method in dbplyr.
Update can be done in Oracle by merge without the insert part.