indices: to support databases >> 1GB on 32-bit systems, normal disk I/O is...

indices: to support databases >> 1GB on 32-bit systems, normal disk I/O is used instead of mmaping to read on-disk indices on a 32-bit VM if the size of the entire database exceeds 500MB

git-svn-id: https://babudb.googlecode.com/svn/trunk@232 d4c7dd96-b7b2-11dd-893d-d98698f66bbf