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Re: BUG #5321: Parallel restore temporarily deadlocked by autovacuum analyze

From: Jerry Gamache <jerry(dot)gamache(at)idilia(dot)com>
To: Tom Lane <tgl(at)sss(dot)pgh(dot)pa(dot)us>
Cc: Alvaro Herrera <alvherre(at)commandprompt(dot)com>, pgsql-bugs(at)postgresql(dot)org
Subject: Re: BUG #5321: Parallel restore temporarily deadlocked by autovacuum analyze
Date: 2010-02-10 15:54:30
Message-ID: 4B72D6B6.4040900@idilia.com (view raw or flat)
Thread:
Lists: pgsql-bugs
I was also surprised that table_y seemed to be involved. This is not a 
typo. Might be caused by a FK constraint between table_y and table_x. 
 From the logs, the autovacuum on table_x was canceled before the one on 
table_y, but the restore only resumed after the autovacuum on table_y 
was canceled. It is possible (but I cannot confirm) that the autovacuum 
thread on table_x was blocked for a while after the cancellation message 
was written to the log. I added timestamps to log_line_prefix to be able 
to give more details if this happens again.

Tom Lane wrote:
> Alvaro Herrera <alvherre(at)commandprompt(dot)com> writes:
>   
>> Jerry Gamache wrote:
>>     
>>> The restore resumed while I was writing this report, and I saw these new
>>> entries in the logs:
>>>
>>> ERROR:  canceling autovacuum task
>>> CONTEXT:  automatic analyze of table "database1.public.table_y"
>>> ERROR:  canceling autovacuum task
>>> CONTEXT:  automatic analyze of table "database1.public.table_y"
>>>       
>
>   
>> This is what I would have expected to happen almost immediately ... what
>> are your autovacuum settings?  And what's your deadlock timeout?
>>     
>
> The other details showed the blockage as being on table_x though.
> Was that a typo in obscuring the details, or did the cancel really
> happen on an unrelated table?
>
> 			regards, tom lane
>
>   


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Next:From: Alvaro HerreraDate: 2010-02-10 16:15:50
Subject: Re: BUG #5321: Parallel restore temporarily deadlocked by autovacuum analyze
Previous:From: Wolfgang FahnenschreiberDate: 2010-02-10 15:42:34
Subject: Postgr. 8.2

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