SUMMARY
I had a crash of akonadictl right after I had asked a restart of akonadi in akonadiconsole. The reason for the restart was kmail being stuck ‘fetching’ a message. (This is always a sign that there's a problem and closing kmail and restarting akonadi is then typically required to get things working again.)

Backtrace by DrKonqi:

Application: akonadictl (akonadictl), signal: Aborted
Using host libthread_db library "/lib64/libthread_db.so.1".
[KCrash Handler]
#6  0x00007f225ec5bf6b in raise () from /lib64/libc.so.6
#7  0x00007f225ec45535 in abort () from /lib64/libc.so.6
#8  0x00007f225f110b85 in qt_message_fatal (context=..., message=<synthetic pointer>...) at global/qlogging.cpp:1907
#9  QMessageLogger::fatal (this=this@entry=0x7ffd4f64d5a0, msg=msg@entry=0x56113c359a40 "Cannot rename log file '%s' to '%s': %s") at global/qlogging.cpp:888
#10 0x000056113c34a978 in akInit (appName=...) at /usr/include/qt5/QtCore/qarraydata.h:208
#11 0x000056113c352d73 in AkApplicationBase::init (this=this@entry=0x7ffd4f64d7e0) at /var/tmp/portage/kde-apps/akonadi-19.08.3/work/akonadi-19.08.3/src/shared/akapplication.cpp:61
#12 0x000056113c35090d in AkApplicationImpl<QCoreApplication>::AkApplicationImpl (this=0x7ffd4f64d7e0, argc=@0x7ffd4f64d73c: 2, argv=0x7ffd4f64d958, loggingCategory=...) at /usr/lib/gcc/x86_64-pc-linux-gnu/9.2.0/include/g++-v9/bits/unique_ptr.h:75
#13 0x000056113c34ae64 in main (argc=<optimized out>, argv=0x7ffd4f64d958) at /var/tmp/portage/kde-apps/akonadi-19.08.3/work/akonadi-19.08.3/src/akonadictl/main.cpp:221
[Inferior 1 (process 20546) detached]


SOFTWARE/OS VERSIONS
KDE Applications: 19.08.3
KDE Plasma Version: 5.16.5
KDE Frameworks Version: 5.64.0
Qt Version: 5.12.5