Number Of Threads Per Shadow Processes Is Increasing (Doc ID 763892.1)

Last updated on MARCH 02, 2009

Applies to:

Oracle Server Enterprise Edition - Version: 10.1 to 11.1
Sun Solaris x86 (32-bit)
Sun Solaris SPARC (64-bit)
Sun Solaris x86-64 (64-bit)
Sun Solaris SPARC (32-bit)
Oracle Server - Enterprise Edition - Version: 10.1 to 11.1

Symptoms

The system is heavily loaded and the run queue is overloaded. Many Oracle shadow processes have many threads, these Oracle shadow processes consume most of the CPU.

Pstack shows that this process has 12 threads:
----------------- lwp# 1 / thread# 1 --------------------
ffffffff7c2d3c7c pollsys (ffffffff7fff1da0, 2, ffffffff7fff1ce0, 0)
... (omitted for better readability, shows Oracle callstack)
----------------- lwp# 2 / thread# 2 --------------------
ffffffff7c2d3a34 kaio (6, 0, ffffffff7c3f7f80, 10, ffffffff7c3f9c18, ffffffff7e900a00)
ffffffff7c2d2e7c _lwp_start (0, 0, 0, 0, 0, 0)
----------------- lwp# 3 / thread# 3 --------------------
ffffffff7c2d2f1c lwp_park (0, ffffffff7b0fbe60, 0)
ffffffff7c2cc748 cond_wait_queue (ffffffff7f5369d8, ffffffff7f5369f8, ffffffff7b0fbe60, 0, 0, 0) + 28
ffffffff7c2ccbac cond_wait_common (ffffffff7f5369d8, ffffffff7f5369f8, ffffffff7b0fbe60, ffffffff7f5369fc, 16, 0) + 2d4
ffffffff7c2ccd38 _cond_timedwait (ffffffff7f5369d8, ffffffff7f5369f8, ffffffff7b0fbf28, 3, ffffffff7f524000, ffffffff7b0fbf38) + 34
ffffffff7f411c08 umem_update_thread (496f0e20, 0, 0, ffffffff7f524000, ffffffff7f5284d8, ffffffff7f537a80) + 218
ffffffff7c2d2e7c _lwp_start (0, 0, 0, 0, 0, 0)

...  (omitted other threads)

----------------- lwp# 12 / thread# 12 --------------------
ffffffff7c2d2f1c lwp_park (0, 0, 0)
ffffffff7c2cc748 cond_wait_queue (10634cfc0, 10634cfd0, 0, 0, ffffffff7c3f9d08, 0) + 28
ffffffff7c2ccca8 cond_wait (10634cfc0, 10634cfd0, 0, 0, 1c00, 0) + 10
ffffffff7c003a60 _aio_idle (10634cf50, 1, 10634cfd0, 0, ffffffff7e905a00, 0) + 28
ffffffff7c0031a8 _aio_do_request (10634cf50, 10000, 0, 0, ffffffff7c0030e4, ffffffff7c108000) + c4
ffffffff7c2d2e7c _lwp_start (0, 0, 0, 0, 0, 0)



Cause

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