akonadiserver lockup with sqlite

[David Faure]

Hi Dan,

Thanks for the advice (in reply to Laurent) on how to debug command handlers in akonadiserver, very useful.

I just used it to debug the test failure from akonadi_sqlite_foldertreewidgettest, which passes with mysql
https://build.kde.org/job/mailcommon%20master%20kf5-qt5/119/PLATFORM=Linux,compiler=gcc/testReport/(root)/TestSuite/akonadi_sqlite_foldertreewidgettest/
(I get the same locally, and it used to work, when I wrote that test)

Here's the backtrace from akonadiserver:

#2  0x00007f72f5b3bea3 in QWaitCondition::wait (this=0x7f72c2ffba48, mutex=0x7f72c2ffba50, time=18446744073709551615) at /d/qt/5/kde/qtbase/src/corelib/thread/qwaitcondition_unix.cpp:215
#3  0x00007f72eb14236c in qSqlite3WaitForUnlockNotify (db=0x7f72b4004ed8) at /d/kde/src/5/kde/pim/akonadi/src/qsqlite/src/sqlite_blocking.cpp:67
#4  0x00007f72eb1423d2 in sqlite3_blocking_step (pStmt=0x7f72b402be98) at /d/kde/src/5/kde/pim/akonadi/src/qsqlite/src/sqlite_blocking.cpp:80
#5  0x00007f72eb143a6c in QSQLiteResultPrivate::fetchNext (this=0x7f72b40295c0, values=empty QVector<QVariant>, idx=0, initialFetch=true) at /d/kde/src/5/kde/pim/akonadi/src/qsqlite/src/qsql_sqlite.cpp:311
#6  0x00007f72eb1450f3 in QSQLiteResult::exec (this=0x7f72b402aab0) at /d/kde/src/5/kde/pim/akonadi/src/qsqlite/src/qsql_sqlite.cpp:555
#7  0x00007f72eb1444fd in QSQLiteResult::reset (this=0x7f72b402aab0, query="BEGIN IMMEDIATE TRANSACTION") at /d/kde/src/5/kde/pim/akonadi/src/qsqlite/src/qsql_sqlite.cpp:427
#8  0x00007f72f67bcb4c in QSqlQuery::exec (this=0x7f72c2ffbfc0, query="BEGIN IMMEDIATE TRANSACTION") at /d/qt/5/kde/qtbase/src/sql/kernel/qsqlquery.cpp:399
#9  0x00007f72f67c0f2a in QSqlDatabase::exec (this=0x7f72b40042a8, query="BEGIN IMMEDIATE TRANSACTION") at /d/qt/5/kde/qtbase/src/sql/kernel/qsqldatabase.cpp:700
#10 0x00000000004d6b27 in Akonadi::Server::DataStore::beginTransaction (this=0x7f72b4004290) at /d/kde/src/5/kde/pim/akonadi/src/server/storage/datastore.cpp:1352
#11 0x000000000052535d in Akonadi::Server::Transaction::Transaction (this=0x7f72c2ffc080, db=0x7f72b4004290, beginTransaction=true) at /d/kde/src/5/kde/pim/akonadi/src/server/storage/transaction.cpp:30
#12 0x000000000056ad26 in Akonadi::Server::Delete::parseStream (this=0x7f72b40181e0) at /d/kde/src/5/kde/pim/akonadi/src/server/handler/delete.cpp:65

How does that unlock-notify stuff work? I don't see any other thread doing anything with sqlite in the backtraces, so what is this thread waiting for?

-- 
David Faure, faure at kde.org, http://www.davidfaure.fr
Working on KDE Frameworks 5