This problem only happens on Windows. The above assertion will
be seen if the number of cpus configured is set to 1. If the
server has > 1 cpu vp, then a server hang can be the result as
the owner of a spin lock will yield, allowing other threads to
run, and if the other threads that run attempt to grab the spin
lock, the owner of the spin lock will not be able to run to
release it (because all the threads attempting to acquire the
spin lock do not give up the cpu vp).
The stack trace in the af file is this (as in theory multiple
database actions could cause the lock table to grow, the only
relevant portion of the stack is the frames above lkmanagex)
(oninit)afhandler
(oninit)afcrash_interface
(oninit)yield_processor_svp
(oninit)mt_yield
(oninit)mt_system
(oninit)invoke_alarmf
(oninit)mt_sysmsg_body
(oninit)lkgrow
(oninit)lkalloc
(oninit)lkmanagex
(oninit)lkrow
(oninit)allocslot
(oninit)alloc_lastpage
(oninit)allocvrow
(oninit)wrt_home
(oninit)wrtrecord
(oninit)rswrite
(oninit)fmwrite
(oninit)aud_sqiswrite
(oninit)chkrowcons
(oninit)addone
(oninit)ins1row
(oninit)insone_next
(oninit)doinsert
(oninit)sq_putinsert
(oninit)sqmain
With multiple cpu vps and a server hang, what would be seen is a
non-running thread (would likely be in a ready state) with a
stack like this:
Stack for thread: 51 sqlexec
base: 0x0000000084868000
len: 167936
pc: 0x0000000140e06b1f
tos: 0x000000008488d6e0
state: ready
vp: 8
NT_yield_processor_mvp ()
mt_yield ()
mt_system ()
invoke_alarmf ()
mt_sysmsg_body ()
lkgrow ()
lkalloc ()
lkmanagex ()
lkitem ()
btnexlock ()
btadditem ()
rsbtadditem ()
isbtadditem ()
fm_idxinsert ()
fmwrite (2, 845ddb80, 848a4b00, 840f5d74)
aud_sqiswrite ()
chkrowcons ()
addone ()
ins1row ()
insone_next ()
doinsert ()
sq_putinsert ()
sqmain ()
And then 1 or more threads running on other cpu vps that are
then spinning on spin lock call from lkalloc like this (these
stacks since the threads are running has to be captured with the
onmode -X s command)
14:48:54 Stack for thread: 48 dbScheduler
base: 0x000000008443f000
len: 135168
pc: 0x0000000140e40318
tos: 0x000000008445ce40
state: running
vp: 8
(oninit)afstack_dump
(oninit)notifyvp_signal_handler
(oninit)mt_nap
(oninit)mt_spin_lock_wait
(oninit)mt_fast_lock
(oninit)lkalloc
(oninit)lkmanagex
(oninit)lktable
(oninit)lkrow
(oninit)gather_records
(oninit)rsread
(oninit)fmread
(oninit)readidx_old
(oninit)gettupl
(oninit)scan_next
(oninit)dodelupd
(oninit)excommand
(oninit)sq_execute
(oninit)mi_exec_prepared_statement
(oninit)ph_task_lock
(oninit)ph_get_next_task
(oninit)db_sched
(oninit)udrlm_clang_execute_internal
(oninit)udrlm_clang_execute
(oninit)udrlm_exec_routine
(oninit)udr_execute
(oninit)dbsched_start_udr
(oninit)th_init_initgls
(oninit)startup |
