Created attachment 118315 [details]
Screenshot of the black "Pixel hole"

SUMMARY
this is the current version of baloo indexer of opensuse Leap 15. As the output seems entirely different of the LMDB bug, I thought it might be of interest.

STEPS TO REPRODUCE
1. Kontact /kmail with several IMAP mailinglist accounts. 
2. go through the emails with the preview and do a search for a search term."Lock the search term". Done the scroll through the mail folder, close the application to the lid without unlocking the search term. 
3. When reopening it from the tray, baloo indexer did crash and the konqi popped up in the tray.
4. in the same moment a "black hole" appears on the screen. I observed this crash / issue also on another account but there (pop) it does not give a backtrace.
The black hole is on a specific position every time, you can see it in the screenshot I do provide. 
5. When you hover on the spot with you mouse it "doubles" as it would expect the border of a window to be resized. 
6. Spectacle is not able to capture this "doubling" it does not take a snapshot of the screen as long as the cursor is over it. 
7. The whole will stay open until you exit the Kontact/Kmail application completely with "exit". 



OBSERVED RESULT
A visual disturbance on the screen and a baloo indexer crash 

EXPECTED RESULT
a clean appearance and no baloo indexer crash (obviously ;-) ) 

SOFTWARE/OS VERSIONS
Windows: 
MacOS: 
Linux/KDE Plasma: 5 opensuse Leap 15 (regular repo rpm)
(available in About System)
KDE Plasma Version: 5.12.6
KDE Frameworks Version: 5.45.0
Qt Version: 5.9.4

ADDITIONAL INFORMATION
Hardware Lenovo X201 (with kernel video driver)
Video Driver Intel 2.1 Mesa 18.02

backtrace:
Application: Baloo File Indexing Daemon (baloo_file), signal: Segmentation fault
Using host libthread_db library "/lib64/libthread_db.so.1".
[Current thread is 1 (Thread 0x7f88b6328100 (LWP 2859))]

Thread 3 (Thread 0x7f88aaf08700 (LWP 4493)):
[KCrash Handler]
#6  0x00007f88b3cf649e in __memmove_sse2_unaligned_erms () from /lib64/libc.so.6
#7  0x00007f88b5332a93 in memcpy (__len=1666392165, __src=<optimized out>, __dest=<optimized out>) at /usr/include/bits/string_fortified.h:34
#8  Baloo::PostingCodec::decode (this=this@entry=0x7f88aaf07997, arr=...) at /usr/src/debug/baloo5-5.45.0-lp150.2.1.x86_64/src/codecs/postingcodec.cpp:42
#9  0x00007f88b5323f64 in Baloo::PostingDB::get (this=this@entry=0x7f88aaf07a80, term=...) at /usr/src/debug/baloo5-5.45.0-lp150.2.1.x86_64/src/engine/postingdb.cpp:100
#10 0x00007f88b5330180 in Baloo::WriteTransaction::commit (this=0x7f489c0121f0) at /usr/src/debug/baloo5-5.45.0-lp150.2.1.x86_64/src/engine/writetransaction.cpp:259
#11 0x00007f88b53294c2 in Baloo::Transaction::commit (this=this@entry=0x7f88aaf07b90) at /usr/src/debug/baloo5-5.45.0-lp150.2.1.x86_64/src/engine/transaction.cpp:262
#12 0x000056421ec216cd in Baloo::NewFileIndexer::run (this=0x564220378290) at /usr/src/debug/baloo5-5.45.0-lp150.2.1.x86_64/src/file/newfileindexer.cpp:75
#13 0x00007f88b4796372 in QThreadPoolThread::run (this=0x5642202c5e60) at thread/qthreadpool.cpp:99
#14 0x00007f88b47990ce in QThreadPrivate::start (arg=0x5642202c5e60) at thread/qthread_unix.cpp:368
#15 0x00007f88b2da2559 in start_thread () from /lib64/libpthread.so.0
#16 0x00007f88b3d4c81f in clone () from /lib64/libc.so.6

Thread 2 (Thread 0x7f88aba4b700 (LWP 2867)):
#0  0x00007f88b3d3db68 in read () from /lib64/libc.so.6
#1  0x00007f88b046ca50 in ?? () from /usr/lib64/libglib-2.0.so.0
#2  0x00007f88b0427c38 in g_main_context_check () from /usr/lib64/libglib-2.0.so.0
#3  0x00007f88b04280d0 in ?? () from /usr/lib64/libglib-2.0.so.0
#4  0x00007f88b042823c in g_main_context_iteration () from /usr/lib64/libglib-2.0.so.0
#5  0x00007f88b49bcbef in QEventDispatcherGlib::processEvents (this=0x7f88a4000b10, flags=...) at kernel/qeventdispatcher_glib.cpp:423
#6  0x00007f88b496509a in QEventLoop::exec (this=this@entry=0x7f88aba4aca0, flags=..., flags@entry=...) at kernel/qeventloop.cpp:212
#7  0x00007f88b47944da in QThread::exec (this=this@entry=0x7f88b5e49d60 <(anonymous namespace)::Q_QGS__q_manager::innerFunction()::holder>) at thread/qthread.cpp:515
#8  0x00007f88b5bd9985 in QDBusConnectionManager::run (this=0x7f88b5e49d60 <(anonymous namespace)::Q_QGS__q_manager::innerFunction()::holder>) at qdbusconnection.cpp:178
#9  0x00007f88b47990ce in QThreadPrivate::start (arg=0x7f88b5e49d60 <(anonymous namespace)::Q_QGS__q_manager::innerFunction()::holder>) at thread/qthread_unix.cpp:368
#10 0x00007f88b2da2559 in start_thread () from /lib64/libpthread.so.0
#11 0x00007f88b3d4c81f in clone () from /lib64/libc.so.6

Thread 1 (Thread 0x7f88b6328100 (LWP 2859)):
#0  0x00007f88b3d4207b in poll () from /lib64/libc.so.6
#1  0x00007f88b0428129 in ?? () from /usr/lib64/libglib-2.0.so.0
#2  0x00007f88b042823c in g_main_context_iteration () from /usr/lib64/libglib-2.0.so.0
#3  0x00007f88b49bcc0b in QEventDispatcherGlib::processEvents (this=0x5642202b28d0, flags=...) at kernel/qeventdispatcher_glib.cpp:425
#4  0x00007f88b496509a in QEventLoop::exec (this=this@entry=0x7ffc09fec6d0, flags=..., flags@entry=...) at kernel/qeventloop.cpp:212
#5  0x00007f88b496d9e4 in QCoreApplication::exec () at kernel/qcoreapplication.cpp:1289
#6  0x000056421ec1921c in main (argc=<optimized out>, argv=<optimized out>) at /usr/src/debug/baloo5-5.45.0-lp150.2.1.x86_64/src/file/main.cpp:104
[Inferior 1 (process 2859) detached]



screenshot (attachment)