"The problem will affect you only if you have multiple reads/writes happening at the same time."
ie. The problem will only manifest if the user is doing anything at all with their computer? :P Interesting analysis - thanks for sharing. -Rowan On Tue, 30 Oct 2018 at 10:13, Simon Slavin <slav...@bigfraud.org> wrote: > This post is about a problem with Apple's new APFS file system. The > problem will affect you only if you have multiple reads/writes happening at > the same time. The problem involves merely slowing of performance, not > corruption of databases or incorrect answers being returned by SQLite. > > Gregory Szorc, expert on Mercurial (revision control and tracking > software) investigated a report that Mercurial was performing slowly on new > Macs, and deduced that the cause was that APFS uses a kernel-level global > lock, not only on writes (expected) but also on reads when no writing was > happening (unexpected). Technical details can be found here: > > <https://gregoryszorc.com/blog/2018/10/29/global-kernel-locks-in-apfs/> > > The more parallel operations are trying to access the storage device, the > slower it gets. > > This post is intended to urge users to avoid premature optimization by > parallel processing, and to consider that slow performance may not be > SQLite's fault. This is not a "Macs suck" post. Please consider the > following text from the article (which comes with relevant links): > > "While this post is about APFS, this issue of global kernel locks during > common I/O operations is not unique to APFS. I already referenced similar > issues in AUFS. And I've encountered similar behaviors with Btrfs (although > I can't recall exactly which operations). And NTFS has its own bag of > problems." > > Simon. > _______________________________________________ > sqlite-users mailing list > sqlite-users@mailinglists.sqlite.org > http://mailinglists.sqlite.org/cgi-bin/mailman/listinfo/sqlite-users > _______________________________________________ sqlite-users mailing list sqlite-users@mailinglists.sqlite.org http://mailinglists.sqlite.org/cgi-bin/mailman/listinfo/sqlite-users
