Mariel Cherkassky <mariel.cherkassky@gmail.com> writes:
> The system catalogs located in the global directory but the global
> directory isnt so big(500K).
You're operating under false assumptions. Only catalogs marked
relisshared are in that directory, other ones are in the per-database
directories.
Somebody mentioned pg_largeobject upthread --- that would definitely
be a candidate to be big, if you're using large objects at all.
regards, tom lane