When I did 'vacuum ;', just found message in below.
" database disk image is malformed."
So, I did like those.
C>sqlite [malformed.db]
sqlite3>.mode insert
sqlite3>.output a.sql
sqlite3>.dump
and continues...
C>sqlite3 new.db
sqlite3>.read a.sql
finally I found the new.db which file size is 0 byte.
any idea?