WARNING: canceling wait for synchronous replication due to user request DETAIL: The transaction has already committed locally, but might not have been replicated to the standby

-------Error--------------

postgres=# INSERT INTO said VALUES ('3954','Saiduzzaman');


^CCancel request sent
WARNING:  canceling wait for synchronous replication due to user request
DETAIL:  The transaction has already committed locally, but might not have been replicated to the standby.
INSERT 0 1
postgres=# exit


Reason

---In Primary--
postgres=# show synchronous_commit;
 synchronous_commit
--------------------
 on
(1 row)

postgres=#
postgres=# select * from pg_stat_replication ;
  pid  | usesysid | usename | application_name |   client_addr   | client_hostname | client_port |         backend_start
        | backend_xmin |   state   | sent_location | write_location | flush_location | replay_location | sync_priority |
sync_state
-------+----------+---------+------------------+-----------------+-----------------+-------------+-----------------------
--------+--------------+-----------+---------------+----------------+----------------+-----------------+---------------+-
-----------
 27148 |    16393 | repuser | walreceiver      | 192.168.159.134 |                 |       40704 | 2017-12-05 01:03:43.09
7386-05 |              | streaming | 0/23015F48    | 0/23015F48     | 0/23015F48     | 0/23015F48      |             0 |
async
(1 row)

postgres=#

postgres=# select application_name, sync_state from pg_stat_replication;
 application_name | sync_state
------------------+------------
 walreceiver      | async
(1 row)

postgres=#

postgres=# show synchronous_standby_names;
 synchronous_standby_names
---------------------------
 pgslave001
(1 row)


---In Standby--
postgres=# show synchronous_commit;
 synchronous_commit
--------------------
 local
(1 row)

postgres=#


------Solution---------

Changing synchronous_standby_names to 'walreceiver' resolved the error.
[root@pg_primary data]# vi postgresql.conf

#synchronous_standby_names = 'pgslave001'

synchronous_standby_names = 'walreceiver'

[root@pg_primary data]# systemctl stop postgresql-9.5.service
[root@pg_primary data]# systemctl start postgresql-9.5.service
[root@pg_primary data]# su - postgres
Last login: Tue Dec  5 01:04:46 EST 2017 on pts/0
-bash-4.2$ psql
psql (9.5.10)
Type "help" for help.

postgres=# INSERT INTO said VALUES ('3690','Nabiul');
INSERT 0 1
postgres=# INSERT INTO said VALUES ('3690','Nabiul');
INSERT 0 1