Re: hung backends stuck in spinlock heavy endless loop
От | Merlin Moncure |
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Тема | Re: hung backends stuck in spinlock heavy endless loop |
Дата | |
Msg-id | CAHyXU0y8SsjeixS6Q4x6BDyEkaDCDLbScep3Sj=FammZXOT3GA@mail.gmail.com обсуждение исходный текст |
Ответ на | Re: hung backends stuck in spinlock heavy endless loop (Andres Freund <andres@2ndquadrant.com>) |
Ответы |
Re: hung backends stuck in spinlock heavy endless loop
(Andres Freund <andres@2ndquadrant.com>)
|
Список | pgsql-hackers |
On Tue, Jan 13, 2015 at 5:21 PM, Andres Freund <andres@2ndquadrant.com> wrote: > On 2015-01-13 15:17:15 -0800, Peter Geoghegan wrote: >> I'm inclined to think that this is a livelock, and so the problem >> isn't evident from the structure of the B-Tree, but it can't hurt to >> check. > > My guess is rather that it's contention on the freelist lock via > StrategyGetBuffer's. I've seen profiles like this due to exactly that > before - and it fits to parallel loading quite well. I think I've got it to pop again. s_lock is only showing 35% (increasing very slowly if at all) but performance is mostly halted. Frame pointer is compiled out. perf report attached. merlin 35.82% postgres [.] s_lock 23.71% postgres [.] tas 14.01% postgres [.] tas 6.82% postgres [.] spin_delay 5.93% postgres [.] LWLockRelease 4.36% postgres [.] LWLockAcquireCommon 2.34% postgres [.] FunctionCall2Coll 1.79% postgres [.] _bt_compare 0.80% postgres [.] LockBuffer 0.52% postgres [.] btoidcmp 0.49% postgres [.] ReleaseAndReadBuffer 0.47% postgres [.] _bt_moveright 0.36% postgres [.] _bt_checkpage 0.36% postgres [.] _bt_relandgetbuf 0.20% perf [.] 0x000000000004312a 0.19% postgres [.] LWLockAcquire 0.13% libv8.so [.] 0x00000000001bbbe0 0.11% libc-2.17.so [.] 0x0000000000151134 0.09% libwebkit.so [.] 0x000000000106ccb7 0.05% libgdk_pixbuf-2.0.so.0.2800.1 [.] 0x00000000000139c7 0.04% Xorg [.] 0x00000000000efb00 0.03% libglib-2.0.so.0.3800.1 [.] 0x00000000000876a2 0.03% [kernel] [k] __ticket_spin_lock 0.02% perf-12966.map [.] 0x00000625db944621 0.02% libskia.so [.] 0x000000000021d15f 0.02% libcairo.so.2.11200.16 [.] 0x000000000002440b 0.02% libpthread-2.17.so [.] __pthread_mutex_unlock_usercnt 0.02% [kernel] [k] copy_user_enhanced_fast_string 0.02% radeon_drv.so [.] 0x0000000000045002 0.02% libpthread-2.17.so [.] pthread_mutex_lock 0.02% [kernel] [k] fget_light 0.01% [kernel] [k] __schedule 0.01% libexa.so [.] 0x0000000000006e1d 0.01% libgdk-x11-2.0.so.0.2400.20 [.] 0x000000000002f0b0 0.01% libvte.so.9.2800.2 [.] 0x0000000000039028 0.01% [radeon] [k] r100_mm_rreg 0.01% [kernel] [k] xhci_irq 0.01% [kernel] [k] native_write_msr_safe 0.01% [kernel] [k] update_cfs_rq_blocked_load 0.01% libglib-2.0.so.0.3800.1 [.] g_hash_table_lookup 0.01% libgobject-2.0.so.0.3800.1 [.] g_type_check_instance_is_a Press '?' for help on key bindings
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