The following bug has been logged on the website:
Bug reference: 12850
Logged by: walter nordmann
Email address: wnordmann(at)gmx(dot)de
PostgreSQL version: 9.4.1
Operating system: Ubuntu 14.4 LTS
Description:
Vacuuming a really big table (139.000.000 records, 66GB tablespace, one
GIN-INDEX of 135 GB!) is consuming extreemly much memory. Much, much more
then maintenance_work_mem (2GB). at this time about 85 GB of virt mem.
see post "autovacuum worker running amok - and me too" at postgresql-general
or ask me for more data. this form is to small for it.
regards
walter