On Wednesday 15 July 2015 23:16:08 Dmitry Smirnov wrote: > On 15/07/15 22:38, David Goodenough wrote: > > I am running sid, so I have 3.8.10.2-1 and I am still getting these > > deadlocks. What gives you the idea that they shoud have gone away? > > Experimentation: I fed ~500 MiB maildir folder to akonadi/sqlite and > deadlocks disappeared with upgrade of sqlite3/libsqlite. It is quite > possible that I did not test long enough however I'm trying to determine > whether it is a real error or merely a warning? > Can you confirm? I suspect that doing something essentially sequential does not show deadlocks. I hit this all the time because I have LOTS of mail filters and they seem to happen while processing those - I guess it spawns processes at least for the spam filter. > > By the way I think I've seen some quiet deadlocks (when akonadi doesn't > do anything while kmail waits for akonadi) even on backend-mysql. I > think akonadi _is_ a problem but I'm just not sure if deadlocks on > sqlite are really that bad, comparing to the whole thing. > > In any case upstream admits that there are problems with concurrent > access on sqlite backend: > > https://techbase.kde.org/Projects/PIM/Akonadi#Why_not_use_sqlite.3F > > So as bad as it sounds sqlite just seems to be a poorly supported > backend... :( My prefered DBM is Postgresql, but it has real problems when updating in that it does not automatically upgrade DBs on update, at least the way that Debian packages it. Also sometimes, especially on sid you get an update where you can not even use the supplied upgrade scripts and you have to do it manually. Having that underlying my email system is not an acceptable risk.
Personally I will not have MySql on my machine, I simply do not trust it. Lots of other systems use Sqlite without problems, and I have to say that my suspicion is that the problems with akonadi are simply becuase it was implemented by people who did not really understand how to use an SQL DB. For instance, a deadlock is a retryable error, you hit it, rollback your transaction and try again. In development this can lead to problems if you do not plan the order in which you access tables, but this is a basic principle of all SQL DBs. So these errors should never appear as errors, they should just trigger an internal retry. Sqlite has had sufficient locking to get around this problem for a while now, and this suggests tha the ordering of table access has simply not been planned properly. All in all this is leading me to an inexorable conclusion, I have will have (after many many years) to give up on kmail and move to something else. My problem is what to move to. I really would like to remain within the KDE world as it will then be better integrated, and I need both IMAP and POP - there appears to be little option. David -- To UNSUBSCRIBE, email to debian-bugs-dist-requ...@lists.debian.org with a subject of "unsubscribe". Trouble? Contact listmas...@lists.debian.org
