This shouldn't be especially surprising - in fact I would expect this to be the case, all other things being equal, for two reasons: firstly, open() followed by

This shouldn't be especially surprising - in fact I would expect this to be the case, all other things being equal, for two reasons: firstly, open() followed by read() involves two kernel-userspace context switches, while SQLite operating on an already open file only needs to call read(), and secondly SQLite is more aggressive about making forwards-incompatible changes than most popular filesystems, giving it more latitude to optimize (ZFS is an exception, but with most filesystems you expect a 10-year old computer to read a disk created yesterday).