I have two oracle databases(8.1.7.4).
One has only one row in the "services summary" stanza of "lsnrctl status"
#lsnrctl status
...
...
Services Summary...
wjjs has 1 service handler(s)

But the other has two rows in the "services summary" stanza of "lsnrctl status"
#lsnrctl status
...
...
Services Summary...
tec has 1 service handler(s)
tec has 1 service handler(s)

What cause the difference between the output of "lsnrctl status" of the two databases.