[PERFORM] Do work_mem and shared buffers have 1g or 2g limit on 64 bit linux?

[Kaijiang Chen]

Hi, I am using postgresql 9.2.10 on centos 6.2, 64 bit version. The server
has 512 GB mem.

The jobs are mainly OLAP like. So I need larger work_mem and shared
buffers. From the source code, there is a constant MaxAllocSize==1GB. So, I
wonder whether work_mem and shared buffers can exceed 2GB in the 64 bit
Linux server?

Thanks and regards,
Kaijiang