Re: [HACKERS] Get stuck when dropping a subscription duringsynchronizing table

On 6/1/17 13:37, Petr Jelinek wrote:
> On 01/06/17 17:32, Masahiko Sawada wrote:
>> On Thu, May 25, 2017 at 5:29 PM, tushar <tushar.ahuja@enterprisedb.com> wrote:
>>> After applying all your patches, drop subscription no  more hangs while
>>> dropping  subscription but there is an error   "ERROR:  tuple concurrently
>>> updated" in the log file of
>>> standby.
>>
>> I tried to reproduce this issue with latest four patches I submit but
>> it didn't happen. I guess this issue doesn't related to the issues
>> reported on this thread and another factor  might be cause of this
>> issue. It would be good to test the same again with latest four
>> patches or after solved current some open items.
> 
> That's because your additional patch kills the workers that do the
> concurrent update. While that's probably okay, I still plan to look into
> making the subscription and state locking more robust.

It seems we have gotten off track here a bit.  What is the current
proposal to fix "tuple concurrently updated" during DROP SUBSCRiPTION?

It seems to me we could just take a stronger lock around
RemoveSubscriptionRel(), so that workers can't write in there concurrently.

-- 
Peter Eisentraut              http://www.2ndQuadrant.com/
PostgreSQL Development, 24x7 Support, Remote DBA, Training & Services