Hi Drake, Thanks for your comments below, I really appreciate your insight on this ;-)
Lynton -----Original Message----- From: sqlite-users-boun...@sqlite.org [mailto:sqlite-users-boun...@sqlite.org] On Behalf Of Drake Wilson Sent: 30 September 2010 12:29 PM To: General Discussion of SQLite Database Subject: Re: [sqlite] SQLite is perfect for FILE based MESSAGE QUEUE? Quoth Lynton Grice <lynton.gr...@logosworld.com>, on 2010-09-30 12:05:18 +0200: > BTW: What is WAL WAL mode uses a write-ahead log instead of a rollback journal, which can help reduce write activity but requires the use of shared memory to keep things consistent between database handles. If I were doing queues in SQLite I would use WAL mode if possible, based on what I read at http://sqlite.org/wal.html. > Also what is the "worst that can happen" with regard > to: > > "...rollback journal activity multiplying the number of synchronized writes. > " The rollback journal essentially implies that each transaction gets synced twice: once to keep the old data in the rollback journal, and once to write the new data. o/` Double the fsyncs, double your dues; it's a statement per transaction with SQLite queues. o/` Problems I can imagine with a plainer ring-buffer-like approach would be along the lines of unclear semantics on the platform side regarding which writes are stable with regard to others, such as whether a crash in the middle of an append is able to corrupt data from beforehand. ISTR SQLite doing fairly extensive work to overcome these kinds of limitations in some cases. > Thanks again > > Lynton ---> Drake Wilson _______________________________________________ sqlite-users mailing list sqlite-users@sqlite.org http://sqlite.org:8080/cgi-bin/mailman/listinfo/sqlite-users _______________________________________________ sqlite-users mailing list sqlite-users@sqlite.org http://sqlite.org:8080/cgi-bin/mailman/listinfo/sqlite-users
