Berkeley DB

DbEnv::set_mp_mmapsize

						#include <db_cxx.h>
						int
						DbEnv::set_mp_mmapsize(size_t mp_mmapsize);
					

Description

Files that are opened read-only in the pool (and that satisfy a few other criteria) are, by default, mapped into the process address space instead of being copied into the local cache. This can result in better-than-usual performance because available virtual memory is normally much larger than the local cache, and page faults are faster than page- copying on many systems. However, in the presence of limited virtual memory, it can cause resource starvation; in the presence of large databases, it can result in immense process sizes.

Set the maximum file size, in bytes, for a file to be mapped into the process address space. If no value is ...