PGError: ERROR: deadlock detected - remove the host_count updates?

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1

I've been googling this error and couldn't find a solution that works. I
even tried a patch without any kind of success. I'm running foreman 1.8.2
(read about this happening in 1.9 also) with postgresql. If more than 4
threads are creating/destroying hosts I encounter PGError: ERROR: deadlock
detected, mostly on updates for host_count column:

{
"error": {"message":"PGError: ERROR: deadlock detected\nDETAIL: Process 19184 waits for ShareLock on transaction 7354368; blocked by process 22793.\nProcess 22793 waits for ExclusiveLock on tuple (4,31) of relation 16525 of database 16385; blocked by process 19184.\nHINT: See server log for query details.\n: UPDATE "domains" SET "hosts_count" = COALESCE("hosts_count", 0) + 1 WHERE "domains"."id" IN (SELECT "domains"."id" FROM "domains" WHERE "domains"."id" = 3 ORDER BY domains.name)"}
}
{
"error": {"message":"PGError: ERROR: deadlock detected\nDETAIL: Process 22773 waits for ExclusiveLock on tuple (2,26) of relation 16503 of database 16385; blocked by process 22793.\nProcess 22793 waits for ShareLock on transaction 7353856; blocked by process 4354.\nProcess 4354 waits for ShareLock on transaction 7354037; blocked by process 22773.\nHINT: See server log for query details.\n: UPDATE "architectures" SET "hosts_count" = COALESCE("hosts_count", 0) - 1 WHERE "architectures"."id" = 1"}
}
I would like to continue handle this by cancelling all this updates for host_count. Do you see a problem with this?
Thanks

2

Hello Ghidu,
There were recently a couple of threads about this issue that had to do
with an extremely large database leading to these deadlocks:
https://groups.google.com/forum/#!topic/foreman-users/0bJd3TPY5MU
https://groups.google.com/forum/#!topic/foreman-users/KHZHi8ktD0s

You could try the solutions suggested in those threads - checking table
sizes to find extremely large ones, expiring reports, verifying all indices
are present, upgrading postgres and foreman.
If they do not help, you could disable the counter_cache for the various
fields and manually update the counters periodically using
foreman-rake fix_cached_counters.
The host counters are only used for informational purposes, so there should
not be any adverse effects other then out-of-date counts.

··· On Fri, Nov 13, 2015 at 10:03 PM, ghidu wrote:

I’ve been googling this error and couldn’t find a solution that works. I
even tried a patch without any kind of success. I’m running foreman 1.8.2
(read about this happening in 1.9 also) with postgresql. If more than 4
threads are creating/destroying hosts I encounter PGError: ERROR: deadlock
detected, mostly on updates for host_count column:

{
“error”: {“message”:“PGError: ERROR: deadlock detected\nDETAIL: Process 19184 waits for ShareLock on transaction 7354368; blocked by process 22793.\nProcess 22793 waits for ExclusiveLock on tuple (4,31) of relation 16525 of database 16385; blocked by process 19184.\nHINT: See server log for query details.\n: UPDATE "domains" SET "hosts_count" = COALESCE("hosts_count", 0) + 1 WHERE "domains"."id" IN (SELECT "domains"."id" FROM "domains" WHERE "domains"."id" = 3 ORDER BY domains.name)”}
}
{
“error”: {“message”:“PGError: ERROR: deadlock detected\nDETAIL: Process 22773 waits for ExclusiveLock on tuple (2,26) of relation 16503 of database 16385; blocked by process 22793.\nProcess 22793 waits for ShareLock on transaction 7353856; blocked by process 4354.\nProcess 4354 waits for ShareLock on transaction 7354037; blocked by process 22773.\nHINT: See server log for query details.\n: UPDATE "architectures" SET "hosts_count" = COALESCE("hosts_count", 0) - 1 WHERE "architectures"."id" = 1”}
}
I would like to continue handle this by cancelling all this updates for host_count. Do you see a problem with this?
Thanks

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Have a nice day,
Tomer Brisker
Red Hat Engineering

3

Thanks Tomer. Did some DB cleanup that seemed to help, a little

··· On Sunday, November 15, 2015 at 10:19:17 AM UTC+2, Tomer Brisker wrote: > > Hello Ghidu, > There were recently a couple of threads about this issue that had to do > with an extremely large database leading to these deadlocks: > https://groups.google.com/forum/#!topic/foreman-users/0bJd3TPY5MU > https://groups.google.com/forum/#!topic/foreman-users/KHZHi8ktD0s > > You could try the solutions suggested in those threads - checking table > sizes to find extremely large ones, expiring reports, verifying all indices > are present, upgrading postgres and foreman. > If they do not help, you could disable the counter_cache for the various > fields and manually update the counters periodically using > `foreman-rake fix_cached_counters`. > The host counters are only used for informational purposes, so there > should not be any adverse effects other then out-of-date counts. > > > On Fri, Nov 13, 2015 at 10:03 PM, ghidu <agh...@gmail.com > > wrote: > >> I've been googling this error and couldn't find a solution that works. I >> even tried a patch without any kind of success. I'm running foreman 1.8.2 >> (read about this happening in 1.9 also) with postgresql. If more than 4 >> threads are creating/destroying hosts I encounter PGError: ERROR: deadlock >> detected, mostly on updates for host_count column: >> >> { >> "error": {"message":"PGError: ERROR: deadlock detected\nDETAIL: Process 19184 waits for ShareLock on transaction 7354368; blocked by process 22793.\nProcess 22793 waits for ExclusiveLock on tuple (4,31) of relation 16525 of database 16385; blocked by process 19184.\nHINT: See server log for query details.\n: UPDATE \"domains\" SET \"hosts_count\" = COALESCE(\"hosts_count\", 0) + 1 WHERE \"domains\".\"id\" IN (SELECT \"domains\".\"id\" FROM \"domains\" WHERE \"domains\".\"id\" = 3 ORDER BY domains.name)"} >> } >> { >> "error": {"message":"PGError: ERROR: deadlock detected\nDETAIL: Process 22773 waits for ExclusiveLock on tuple (2,26) of relation 16503 of database 16385; blocked by process 22793.\nProcess 22793 waits for ShareLock on transaction 7353856; blocked by process 4354.\nProcess 4354 waits for ShareLock on transaction 7354037; blocked by process 22773.\nHINT: See server log for query details.\n: UPDATE \"architectures\" SET \"hosts_count\" = COALESCE(\"hosts_count\", 0) - 1 WHERE \"architectures\".\"id\" = 1"} >> } >> I would like to continue handle this by cancelling all this updates for host_count. Do you see a problem with this? >> Thanks >> >> >> -- >> You received this message because you are subscribed to the Google Groups >> "Foreman users" group. >> To unsubscribe from this group and stop receiving emails from it, send an >> email to foreman-user...@googlegroups.com . >> To post to this group, send email to forema...@googlegroups.com >> . >> Visit this group at http://groups.google.com/group/foreman-users. >> For more options, visit https://groups.google.com/d/optout. >> > > > > -- > Have a nice day, > Tomer Brisker > Red Hat Engineering >