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

On 05/25/2017 12:44 AM, Petr Jelinek wrote:
> There is still outstanding issue that sync worker will keep running
> inside the long COPY because the invalidation messages are also not
> processed until it finishes but all the original issues reported here
> disappear for me with the attached patches applied.
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.

---
logical replication synchronization worker finished processing
2017-05-25 09:15:52.654 BST [18575] LOG:  logical replication 
synchronization worker finished processing
2017-05-25 09:15:52.656 BST [18563] LOG:  starting logical replication 
worker for subscription "sub"
2017-05-25 09:15:52.662 BST [18577] LOG:  logical replication sync for 
subscription sub, table t14 started
2017-05-25 09:15:53.657 BST [18563] LOG:  starting logical replication 
worker for subscription "sub"
2017-05-25 09:15:53.663 BST [18579] LOG:  logical replication sync for 
subscription sub, table t15 started
2017-05-25 09:15:53.724 BST [18563] FATAL:  terminating logical 
replication worker due to administrator command
2017-05-25 09:15:53.725 BST [18521] LOG:  worker process: logical 
replication worker for subscription 16684 (PID 18563) exited with exit 
code 1
2017-05-25 09:15:54.734 BST [18579] ERROR:  tuple concurrently updated
2017-05-25 09:15:54.735 BST [18577] ERROR:  tuple concurrently updated
2017-05-25 09:15:54.736 BST [18521] LOG:  worker process: logical 
replication worker for subscription 16684 sync 16426 (PID 18579) exited 
with exit code 1
2017-05-25 09:15:54.736 BST [18521] LOG:  worker process: logical 
replication worker for subscription 16684 sync 16423 (PID 18577) exited 
with exit code 1
~
~
~

Steps to reproduce -
X cluster -> create 100 tables , publish all tables  (create publication 
pub for all tables);
Y Cluster -> create 100 tables ,create subscription(create subscription 
sub connection 'user=centos host=localhost' publication pub;
Y cluster ->drop subscription - drop subscription sub;

check the log file on Y cluster.

Sometime , i have seen this error on psql prompt and drop subscription 
operation got failed at first attempt.

postgres=# drop subscription sub;
ERROR:  tuple concurrently updated
postgres=# drop subscription sub;
NOTICE:  dropped replication slot "sub" on publisher
DROP SUBSCRIPTION

-- 
regards,tushar
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