sqlite by default creates the journal file at the start of a transaction,which is a good thing. Normally it deletes the file upon commit.

You can change this behavior to simply truncate the file (no create/delete necessary) or to zero it,via a PRAGMA sql command. Not all options may be supported on your version of sqlite.

PRAGMA journal_mode = DELETE | TRUNCATE | PERSIST | MEMORY | OFF

Write operations are normally not completed until you COMMIT,which is implemented by truncating,deleting,or invalidating the journal.

If this behavior is new,I have no explanation for why it might have changed,other than perhaps an upgrade of sqlite changed default behavior,or has become more sophisticated by not reopening the journal for every transaction.

来自：http://stackoverflow.com/questions/633274/what-causes-a-journal-file-to-be-created-in-sqlite