Ocssd.Bin Process Consumes 100% Cpu (Doc ID 730148.1)

Last updated on JUNE 28, 2017

Applies to:

Oracle Database - Enterprise Edition - Version 11.1.0.6 and later
Linux x86
***Checked for relevance on 12-Jan-2010***


Symptoms

Suddenly 100% CPU being consumed by ocssd.bin.  ASM and database instances hang.

OS Watcher

Linux OSW v2.1.1
zzz ***Tue Feb 19 23:00:02 EET 2008

top - 23:00:06 up 25 days, 22:09, 1 user, load average: 1.34, 1.47, 1.40
Tasks: 246 total, 3 running, 243 sleeping, 0 stopped, 0 zombie
Cpu(s): 0.5%us, 12.2%sy, 0.0%ni, 87.3%id, 0.0%wa, 0.0%hi, 0.0%si, 0.0%st
Mem: 12302040k total, 12033140k used, 268900k free, 240296k buffers
Swap: 4192956k total, 167508k used, 4025448k free, 10565016k cached

PID USER PR NI VIRT RES SHR S %CPU %MEM TIME+ COMMAND
4258 oracle RT 0 298m 212m 39m S 100 1.8 55:23.29 /oracle/db/bin/ocss
10696 oracle 18 0 8554m 132m 27m S 0 1.1 7:32.97 ora_asmb_bymdw

top shows ocssd.bin is the top CPU consumer.

"strace.log" From strace, it looks thread 11 (LWP 4358) spins on "poll" system call.

4358  poll([{fd=12, events=POLLIN|POLLRDNORM}, {fd=13, events=POLLIN|POLLRDNORM},
4358  poll([{fd=12, events=POLLIN|POLLRDNORM}, {fd=13, events=POLLIN|POLLRDNORM},
4358  poll([{fd=12, events=POLLIN|POLLRDNORM}, {fd=13,events=POLLIN|POLLRDNORM},
4358  poll([{fd=12, events=POLLIN|POLLRDNORM}, {fd=13,events=POLLIN|POLLRDNORM},

pstack from 4358:

        Thread 11 (Thread 1136679232 (LWP 4358)):
    #0  0x0000003e6fac5896 in poll () from /lib64/libc.so.6
    #1  0x00002aaaac0b953f in ntevpque () from /oracle/db/lib/libclntsh.so.11.1
    #2  0x00002aaaac0b1c96 in ntevqone () from /oracle/db/lib/libclntsh.so.11.1
    #3  0x00002aaaabfd1117 in nsevreap () from /oracle/db/lib/libclntsh.so.11.1
    #4  0x00002aaaabfa63ba in nsdo () from /oracle/db/lib/libclntsh.so.11.1
    #5  0x00002aaaac1f9921 in nsfull_sd () from /oracle/db/lib/libclntsh.so.11.1
    #6  0x00002aaaac206bdd in nssend () from /oracle/db/lib/libclntsh.so.11.1
    #7  0x00002aaaaab28539 in clsc_send_msg () from /oracle/db/lib/libhasgen11.so
    #8  0x00002aaaaab27d67 in clsc_send () from /oracle/db/lib/libhasgen11.so
    #9  0x00002aaaaab2a4eb in clsc_send_client ()
    #10 0x00002aaaaab00a3a in clscsendx () from /oracle/db/lib/libhasgen11.so
    #11 0x00002aaaaab25ddf in clsc_answer () from /oracle/db/lib/libhasgen11.so
    #12 0x00002aaaaab1559d in clsc_event_hndlr ()
    #13 0x00002aaaaab131b8 in clsc_event_ext () from /oracle/db/lib/libhasgen11.so
    #14 0x00002aaaaab0ff8c in clsc_select_ext () from /oracle/db/lib/libhasgen11.so
    #15 0x00002aaaaab0496d in clsc_select () from /oracle/db/lib/libhasgen11.so
    #16 0x00002aaaaaaffd54 in clscselect () from /oracle/db/lib/libhasgen11.so
    #17 0x00000000004441ef in clssgmclientlsnr ()
    #18 0x000000000040977a in clssscthrdmain ()
    #19 0x0000003e706062e7 in start_thread () from /lib64/libpthread.so.0
    #20 0x0000003e6face3bd in clone () from /lib64/libc.so.6

CSS deamons consumes cpu on one of its threads: clssnmPollingThread.

Cause

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