My connection is getting reset if i use serial datatype

When I was trying to load the data in a table which contains serial data type it is resting postmaster.

Here are the steps for reproducing:

Here is our test case:

`test=# \des
List of foreign servers
Name | Owner | Foreign-data wrapper
---------------+----------+----------------------
cstore_server | postgres | cstore_fdw
(1 row)

test=# \det
List of foreign tables
Schema | Table | Server
--------+-------+---------------
public | c1 | cstore_server
(1 row)

test=# \d+ c1
Foreign table "public.c1"
Column | Type | Modifiers | FDW Options | Storage | Stats target | Description
--------+-------------------+-------------------------------------------------+-------------+----------+--------------+-------------
id | integer | not null default nextval('c1_id_seq'::regclass) | | plain | |
name | character varying | | | extended | |
Server: cstore_server
FDW Options: (compression 'pglz')

test=# \q
[postgres@localhost ~]$ vi c1.csv
[postgres@localhost ~]$ cat c1.csv
test
test

[postgres@localhost ~]$ psql test
psql (9.6.6)
Type "help" for help.

test=#
test=#
test=#
test=# copy c1(name) from '/home/postgres/c1.csv' WITH csv;
server closed the connection unexpectedly
This probably means the server terminated abnormally
before or while processing the request.
The connection to the server was lost. Attempting reset: Failed.
!> \q

From log file same error what we have seen in you case.

< 2017-12-21 19:30:02.792 IST > LOG: server process (PID 90463) was terminated by signal 11: Segmentation fault
< 2017-12-21 19:30:02.792 IST > DETAIL: Failed process was running: copy c1(name) from '/home/postgres/c1.csv' WITH csv;
< 2017-12-21 19:30:02.792 IST > LOG: terminating any other active server processes
< 2017-12-21 19:30:02.796 IST > WARNING: terminating connection because of crash of another server process
< 2017-12-21 19:30:02.796 IST > DETAIL: The postmaster has commanded this server process to roll back the current transaction and exit, because another server process exited abnormally and possibly corrupted shared memory.
< 2017-12-21 19:30:02.796 IST > HINT: In a moment you should be able to reconnect to the database and repeat your command.
< 2017-12-21 19:30:02.802 IST > WARNING: terminating connection because of crash of another server process
< 2017-12-21 19:30:02.802 IST > DETAIL: The postmaster has commanded this server process to roll back the current transaction and exit, because another server process exited abnormally and possibly corrupted shared memory.
< 2017-12-21 19:30:02.802 IST > HINT: In a moment you should be able to reconnect to the database and repeat your command.
< 2017-12-21 19:30:02.833 IST > FATAL: the database system is in recovery mode
< 2017-12-21 19:30:02.834 IST > LOG: all server processes terminated; reinitializing
< 2017-12-21 19:30:02.967 IST > LOG: database system was interrupted; last known up at 2017-12-21 19:22:30 IST
< 2017-12-21 19:30:03.016 IST > LOG: database system was not properly shut down; automatic recovery in progress
< 2017-12-21 19:30:03.032 IST > LOG: redo starts at 0/1AC9658
< 2017-12-21 19:30:03.032 IST > LOG: invalid record length at 0/1ACB380: wanted 24, got 0
< 2017-12-21 19:30:03.032 IST > LOG: redo done at 0/1AC9658
< 2017-12-21 19:30:03.052 IST > LOG: MultiXact member wraparound protections are now enabled
< 2017-12-21 19:30:03.066 IST > LOG: database system is ready to accept connections
< 2017-12-21 19:30:03.099 IST > LOG: autovacuum launcher started

If I replace serial data type with integer which is not using the sequence to generate the values(automatically) then we are not facing this issue.

test=# create foreign table c1 (id int,name varchar) SERVER cstore_server
OPTIONS(compression 'pglz');
CREATE FOREIGN TABLE
test=#
test=#
test=#
test=# copy c1(name) from '/home/postgres/c1.csv' WITH csv;
COPY 3
test=# select * from c1 ;
id | name
----+------
| test
| test
|
(3 rows)`