Is there a difference between the SQL constant user and the function dbmsinfo(username)?
The SQL constant user is used for compatibility with older versions of Ingres – its datatype is c32. dbmsinfo(‘username’) is the preferred method to reference the current user and has a datatype of char(32). Because the datatypes are different this can lead to differences in query performance. If you have a where clause with char_col=user then each value of char_col has to be coerced to a c32 – causing a table scan even if there is an index available.