Finding Out If Threads Are Suspended

To find out if threads are suspended, use one or all of these methods:

• Examine the message log for suspended-thread alarm messages.
• Run onstat -u.
• Run onstat -g ath.
• Run onstat -g con.

When you know the number of the session that spawned the suspended thread, you can also run onstat -g ses session_number.

Examples of Suspended Thread Output

The following output examples show a suspended thread. In all output, the word defunct marks the suspended thread.

The onstat -u output shows the following user-thread information:

Userthreads
address  flags   sessid  user  tty   wait tout locks nreads  nwrites
b3a4018  ---P--D 9       root   -   0     0    0     40      21
...
b3a7244  DEFUNCT 18   informix  -   -     -    -     -       -
14 active, 128 total, 15 maximum concurrent

The onstat -g ath output shows the following list of threads:

Threads:
tid   tcb      rstcb    prty status              vp-class name
2     b336730  0        2    running             2adm     adminthd
...
45    b93b670  b3a6a8c  2    sleeping secs: 27   1cpu     bum_sched
47    b93be88  0        2    yield forever       1cpu     bum_rcv
52    b990278  b3a66b0  2    cond wait  sm_read  1cpu   sqlexec_1.15
53    b9906b8  b3a6e68  2    yield forever       1cpu    x_exec_1.15
54    b990c68  b3a7244  2    cond wait  defunct  1cpu     x_update_0

The onstat -g con output shows the following waiting conditions:

Conditions with waiters:
cid      addr             name               waiter   waittime
271      b990230          sm_read            52       105     
273      b990f70          defunct            54       110 

When you run onstat -g ses 18 to examine session 18,
you see the following output:

          local                                    #RSAM    total      used       Start     Accum
sessid    sessid user     tty      pid   hostname  threads  memory     memory     Time      Time    
1.15      18     informix  -       8925  -         2        90112      61592      08:32:00  -

tid   tcb     rstcb    flags    curstk status              name
53    b9906b8 b3a6e68  ---P---  912    yield forever       x_exec_1.15
54    b990c68 b3a7244  DEFUNCT  5560   cond wait(defunct)  x_update_0

Memory pools    count 1
name   class addr      totalsize freesize  #allocfrag #freefrag 
18     V     ba85018   90112     28520     180        10        

name      free     used      name       free       used
overhead  0        128       scb        0          96 
... 
sqtcb     0        1016      fragman    0          1232

|--Session ID--|  SQL            Current            Iso Lock      SQL  ISAM F.E. Submit   Admit    Current 
Global     Local  Stmt type      Database           Lvl Mode      ERR  ERR  Vers Time     Time     Role    
1.24       24     SELECT         sales              CR  Not Wait  0    0    8.50 08:32:00 -        - 
No current SQL statement.

Examples of Output After the Suspended Thread Exits

After the session that spawned the suspended thread exits, you see the following output for onstat -u, which shows that no session is associated with the suspended thread:

Userthreads
address  flags   sessid  user     tty   wait  tout locks  nreads  nwrites
b3a4018  ---P--D 9       root     -    0     0    0      40      21
...
b3a7244  DEFUNCT -        informix -   -     -    -      -       -
12 active, 128 total, 15 maximum concurrent

For more information on these onstat options, see the chapter on the Resource Grant Manager in your IBM Informix: Performance Guide and onstat: Monitor Database Server Operations.