Onstat -U

Userthreads
address  flags sessid   user     tty      wait     tout locks nreads   nwrites
a4d8018  ---P--D 1        informix -        0        0    0     58       4595
a4d8628  ---P--F 0        informix -        0        0    0     0        2734
a4d8c38  ---P--- 5        informix -        0        0    0     0        1
a4d9248  ---P--B 6        informix -        0        0    0     40       0
a4d9858  ---P--D 7        informix -        0        0    0     0        0
a4d9e68  Y--P--- 21       niraj    -        a65e5a8  0    1     0        0
6 active, 128 total, 7 maximum concurrent

Provides the status of the session.
The flag codes for position 1:
B  Waiting for a buffer
C  Waiting for a checkpoint
G  Waiting for a write of the logical-log buffer
L  Waiting for a lock
S  Waiting for mutex
T  Waiting for a transaction
Y  Waiting for condition
X  Waiting for a transaction cleanup (rollback)

The flag code for position 2:
*  Transaction active during an I/O failure

The flag code for position 3:
A  A dbspace backup thread
For other values that appear here, see the third position of flag codes for the -x option.

The flag code for position 4:
P  Primary thread for a session

The flag codes for position 5:
R  Reading
X  Thread in critical section

The flag codes for position 7:
B  A B-tree cleaner thread
C  Terminated user thread waiting for cleanup
D  A daemon thread
F  A page-cleaner thread
M  Special ON–Monitor thread (UNIX