On Thu, Sep 28, 2017 at 1:16 PM, pisymbol . <pisym...@gmail.com> wrote:
> > > On Thu, Sep 28, 2017 at 11:55 AM, Simon Slavin <slav...@bigfraud.org> > wrote: > >> >> >> On 28 Sep 2017, at 3:31pm, pisymbol . <pisym...@gmail.com> wrote: >> >> > Specificially, if thread 1 and 2 both have a handle to sqlite3 with full >> > mutex, then both could start a transaction simultaneously, one will win >> the >> > other will wait, [snip] >> >> By "serialised" the documentation means that no two SQL commands will be >> allowed to take place at the same time. But SQL can’t separate your two >> different threads into two different sources of commands. As far as its >> concerned, anything which uses your single connection is part fo the same >> command-stream. So if one part of your program executes BEGIN then >> everything from any source from then onwards is part of the same >> transaction until some part of your program executes "COMMIT". >> >> If you want your program to execute two different transactions at the >> same time (and handle the bookkeeping necessary to make one wait for the >> other to complete) you must use two different connections. And if you have >> three independent parts of your program which may all depend on transaction >> isolation, you need three connections >> > > So even with full mutex, if I have thread 1 issue a "BEGIN" and it starts > processing, and another thread 2 issues a "BEGIN" somewhere in between > that, the other thread will just flat out fail because a transaction has > already started for thread 1. Is that correct? > > MAN, the doc is very unclear about this. > > The follow-up to this is what is the purpose of full mutex mode and when should it be used over no mutex mode? I was using no mutex for a while until I thought full mutex might simplify things a lot (pass one connection pointer around a few threads etc.). I guess it would if I used auto-commit mode instead, right? -aps _______________________________________________ sqlite-users mailing list sqlite-users@mailinglists.sqlite.org http://mailinglists.sqlite.org/cgi-bin/mailman/listinfo/sqlite-users
