server closed the connection unexpectedly when pg_dump - postgresql

Question

i am run pg_dump on my vps server, it throw me error:
pg_dump: [archiver (db)] query failed: server closed the connection unexpectedly
This probably means the server terminated abnormally
before or while processing the request.
pg_dump: [archiver (db)] query was: SELECT
( SELECT alias FROM pg_catalog.ts_token_type('22171'::pg_catalog.oid) AS t
WHERE t.tokid = m.maptokentype ) AS tokenname,
m.mapdict::pg_catalog.regdictionary AS dictname
FROM pg_catalog.pg_ts_config_map AS m
WHERE m.mapcfg = '22172'
ORDER BY m.mapcfg, m.maptokentype, m.mapseqno
Then I notice the sql on the above error:
SELECT
( SELECT alias FROM pg_catalog.ts_token_type('22171'::pg_catalog.oid) AS t
WHERE t.tokid = m.maptokentype ) AS tokenname,
m.mapdict::pg_catalog.regdictionary AS dictname
FROM pg_catalog.pg_ts_config_map AS m
WHERE m.mapcfg = '22172'
ORDER BY m.mapcfg, m.maptokentype, m.mapseqno
So I try to run SELECT alias FROM pg_catalog.ts_token_type('22171'::pg_catalog.oid) on psql
So it throw me error:
pzz_development=# SELECT alias FROM pg_catalog.ts_token_type('22171'::pg_catalog.oid);
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
How can I figure out the problem, and dump my data properly?
EDIT:
Then i check postgresql log at /var/log/postgresql/postgresql-9.3-main.log
2015-08-10 16:22:49 CST LOG: server process (PID 4029) was terminated by signal 11: Segmentation fault
2015-08-10 16:22:49 CST DETAIL: Failed process was running: SELECT
( SELECT alias FROM pg_catalog.ts_token_type('22171'::pg_catalog.oid) AS t
WHERE t.tokid = m.maptokentype ) AS tokenname,
m.mapdict::pg_catalog.regdictionary AS dictname
FROM pg_catalog.pg_ts_config_map AS m
WHERE m.mapcfg = '22172'
ORDER BY m.mapcfg, m.maptokentype, m.mapseqno
2015-08-10 16:22:49 CST LOG: terminating any other active server processes
2015-08-10 16:22:49 CST WARNING: terminating connection because of crash of another server process
2015-08-10 16:22:49 CST 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.
2015-08-10 16:22:49 CST HINT: In a moment you should be able to reconnect to the database and repeat your command.
2015-08-10 16:22:49 CST LOG: all server processes terminated; reinitializing
2015-08-10 16:22:49 CST LOG: database system was interrupted; last known up at 2015-08-10 16:22:45 CST
2015-08-10 16:22:50 CST LOG: database system was not properly shut down; automatic recovery in progress
2015-08-10 16:22:50 CST LOG: unexpected pageaddr 0/2AE6000 in log segment 000000010000000000000004, offset 11427840
2015-08-10 16:22:50 CST LOG: redo is not required
2015-08-10 16:22:50 CST LOG: MultiXact member wraparound protections are now enabled
2015-08-10 16:22:50 CST LOG: autovacuum launcher started
2015-08-10 16:22:50 CST LOG: database system is ready to accept connections