Jeff, I can agree that on Windows mutex performance can be awful especially in such frequently called place as pcache1Fetch. So you have only two options to solve the problem: 1) Split threads into different processes - make it one thread per process. 2) Make your own implementation of pcache. You can probably just take SQLite's implementation and change usage of mutex to spin lock for example, or make it work with TLS to make threads completely independent. In latter case you have to be sure that each connection is used solely in one thread though.
Pavel On Mon, Oct 18, 2010 at 1:24 PM, Powell, Jeff <jeff.pow...@sap.com> wrote: > I did some profiling of our current application through the Intel Parallel > Studio tools, and it identified the mutex in pcache1Fetch as the primary > source of waits. Each thread acts on its own, sharing nothing with the other > threads, so I would expect that there is zero waiting. > > -Jeff > > -----Original Message----- > From: sqlite-users-boun...@sqlite.org > [mailto:sqlite-users-boun...@sqlite.org] On Behalf Of Pavel Ivanov > Sent: Monday, October 18, 2010 12:03 PM > To: General Discussion of SQLite Database > Subject: Re: [sqlite] Scaling of Cache > >> In pcache1Fetch, sqlite mutexes around the cache handling, which appears to >> be causing significant waits/scalability issues in my application. If I >> disable this mutex, the application crashes. > > Why do you think that this mutex causes significant waits? > Anyway ... > >> Is it possible to cache on a thread-by-thread basis such that no mutexes are >> necessary? > > You can make your own pcache implementation which will work > independently between threads and thus probably consume a lot more > memory than it is now. > > > Pavel > > On Mon, Oct 18, 2010 at 12:25 PM, Powell, Jeff <jeff.pow...@sap.com> wrote: >> I'm seeing some scaling issues (which I'm hoping someone else has >> encountered before). I have an application which utilizes multiple threads, >> each of which never writes to the database, and none of which shares its >> cache. >> >> In pcache1Fetch, sqlite mutexes around the cache handling, which appears to >> be causing significant waits/scalability issues in my application. If I >> disable this mutex, the application crashes. >> >> Is it possible to cache on a thread-by-thread basis such that no mutexes are >> necessary? >> >> -Jeff >> >> >> _______________________________________________ >> 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 > _______________________________________________ > 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
