Angus March <an...@uducat.com> wrote: > Pavel Ivanov wrote: >>> Hell if I know why they use fcntl() for locks, and don't even give >>> you the option to block. >>> >> >> I think because they need to detect dead locks. BTW, I believe in >> case of dead lock even busy_handler will not be called, just >> SQLITE_BUSY is returned... >> > I guess that makes sense, in cases where multiple tables are > involved.
It doesn't matter whether a single or multiple tables are involved - SQLite locks at the database level. The deadlock occurs when 1) transaction A starts to read, taking a SHARED lock; 2) transaction B prepares to write, taking a RESERVED lock; 3) transaction A now wants to write, too. At this point, transaction B is waiting for all readers (one of which is transaction A) to clear, while transaction A waits for the previous writer (which is transaction B) to complete. Igor Tandetnik _______________________________________________ sqlite-users mailing list sqlite-users@sqlite.org http://sqlite.org:8080/cgi-bin/mailman/listinfo/sqlite-users
