On Tue, Aug 13, 2013 at 11:35 AM, Ralf Ramsauer <r...@ramses-pyramidenbau.de > wrote:
> Now my Question: > According to [4], it seems that NFS also has problems with sharing > locks. So why does Sqlite make use of file locks instead of writing > those locks (including a timestamp for expiration) inside the database > file or by touching dotfiles for locking? > You cannot write into the database file to create a lock because that presents a race condition if two processes are trying to lock at the same time. If you open using the "unix-dotfile" VFS, it will use dotfile locking. However, you give up a lot of concurrency with this (since dot-files are always exclusive locks and never reader/writer locks) and it is slower and it does not work with WAL mode (which requires multiple reader/writer locks per file) and if your process dies unexpectedly it will leave stale locks that have to be removed by hand. -- D. Richard Hipp d...@sqlite.org _______________________________________________ sqlite-users mailing list sqlite-users@sqlite.org http://sqlite.org:8080/cgi-bin/mailman/listinfo/sqlite-users
