I am facing a strange problem and thats bugging me for a long time,
I am using postgres version 7.2.1.
I have written an application in C which tries to drop a trigger and simultaneously read from a table thats has data related to that trigger.
the whole database comes into a deadlock stage where drop() keeps waiting on one hand and select() keeps waiting on other hand.
i have the stack trace of the processes that are performing the operation
For Drop:
process doing drop trigger
(gdb) where
#0 0x420e8a42 in semop () from /lib/i686/libc.so.6
#1 0x0810f028 in IpcSemaphoreLock ()
#2 0x081132c0 in ProcSleep ()
#3 0x081124e5 in WaitOnLock ()
#4 0x08112289 in LockAcquire ()
#5 0x081116d8 in LockRelation ()
#6 0x0807407b in relation_openr ()
#7 0x08074195 in heap_openr ()
#8 0x080bed34 in DropTrigger ()
#9 0x081176c7 in pg_exec_query_string ()
#10 0x0811876a in PostgresMain ()
#11 0x080fde2a in DoBackend ()
#12 0x080fd77d in BackendStartup ()
#13 0x080fc8c1 in ServerLoop ()
#14 0x080fc2db in PostmasterMain ()
#15 0x080da152 in main ()
#16 0x42017499 in __libc_start_main () from /lib/i686/libc.so.6
(gdb)
For Select()
process's doing select
(gdb) where
#0 0x420e8a42 in semop () from /lib/i686/libc.so.6
#1 0x0810f028 in IpcSemaphoreLock ()
#2 0x081132c0 in ProcSleep ()
#3 0x081124e5 in WaitOnLock ()
#4 0x08112289 in LockAcquire ()
#5 0x081116d8 in LockRelation ()
#6 0x0807407b in relation_openr ()
#7 0x08074195 in heap_openr ()
#8 0x0810905a in fireRIRrules ()
#9 0x08108e21 in ApplyRetrieveRule ()
#10 0x08109134 in fireRIRrules ()
#11 0x08108ff9 in fireRIRrules ()
#12 0x08108e21 in ApplyRetrieveRule ()
#13 0x08109134 in fireRIRrules ()
#14 0x08108e21 in ApplyRetrieveRule ()
#15 0x08109134 in fireRIRrules ()
#16 0x081095ec in QueryRewrite ()
#17 0x081173c9 in pg_analyze_and_rewrite ()
#18 0x08117635 in pg_exec_query_string ()
#19 0x0811876a in PostgresMain ()
#20 0x080fde2a in DoBackend ()
#21 0x080fd77d in BackendStartup ()
#22 0x080fc8c1 in ServerLoop ()
---Type <return> to continue, or q <return> to quit---
#23 0x080fc2db in PostmasterMain ()
#24 0x080da152 in main ()
#25 0x42017499 in __libc_start_main () from /lib/i686/libc.so.6
(gdb)
Looks like both try to have a lock and that leads to a deadlock situation.
internally does drop trigger and select try to lock a particluar table?
how can i get details whats happening internally in postgres for these operations?
I can provide more info if needed, hope the stack traces are helpful.
Kindly help me, this problem is causinig lot of problem for me.
Thanks in advance
regards
vatsal
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