tar.gz as file system to mount

In todays Linux news was article about ability of kernel to use tar.gz as file system.

It remembered me description of Sybase IQ, that uses compression for stored data.

Also I read about squashfs that after it installing system works faster, for example on Asus EEE pc.
However it seems that it will cause faster battery discharge, due to high processor usage in that case.

It seems that such filesystems could be very effective for using in database that is mainly used for reading.

Just need time to check it in experiment.

Also interesting how mmap function works for this type of filesystems.

link:
how to mount FUSE filesystem