On Thu, Sep 20, 2012 at 9:12 AM, Sebastian Krysmanski < sql...@lists.manski.net> wrote:
> Hi, > > I'm trying to use SQLite in a multi-threaded application. I've done some > tests and it seems that using the same connection on multiple threads is > faster than having one connection per thread. > > However, http://www.sqlite.org/c3ref/errcode.html states: > > "When the serialized threading mode (http://www.sqlite.org/threadsafe.html) > is in use, it might be the case that a second error occurs on a separate > thread in between the time of the first error and the call to these > interfaces. When that happens, the second error will be reported since > these interfaces always report the most recent result." > > So, this is a problem in my application (and I definitely need multi > threading). > > Obtaining an exclusive lock for the database connection, as suggested in > the documentation, is not an option for me because even read only > statements (SELECT) can potentially return an error. And obtaining an > exclusive lock for a read statement eliminates all concurrency there is in > SQLite. > Every operation on an SQLite database connection operates under an exclusive mutex on that database connection, so you don't have any concurrency anyhow. > > So the only solution I can come up with is to make "sqlite3_errmsg()" (and > related functions) use thread local memory. > > Is there (or has there ever been made) any attempt on storing the error > message in thread local memory? (I'm a C# and Java developer, so I'm not > sure whether thread local memory even exists in C. It does in C# and Java > though.) > Thread local storage has been available to C code since long before Java and C# were even invented. But it is accessed through library routines that are not cross-platform, so we are not interested in using it in SQLite. Furthermore, making such a change would break backwards compatibility, which is a huge no-no with SQLite. Best regards > Sebastian > > _______________________________________________ > sqlite-users mailing list > sqlite-users@sqlite.org > http://sqlite.org:8080/cgi-bin/mailman/listinfo/sqlite-users > -- D. Richard Hipp d...@sqlite.org _______________________________________________ sqlite-users mailing list sqlite-users@sqlite.org http://sqlite.org:8080/cgi-bin/mailman/listinfo/sqlite-users
