BUG #12909: pg_dump error

The following bug has been logged on the website:

Bug reference:      12909
Logged by:          dreamsxin
Email address:      dreamsxin@qq.com
PostgreSQL version: 9.4.1
Operating system:   Ubuntu 12.04
Description:

pg_dump output:

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('16392'::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 = '69497'
ORDER BY m.mapcfg, m.maptokentype, m.mapseqno