Trying to hunt down a lockup

General
1

I have a stack dump from Activity Monitor here that is giving me some trouble, and I’m looking for some thoughts.

For all intents and purposes, I have three threads: the main and two import threads. I also have a SQLite database. As I’ve setup my database, the main thread is never allowed to write to the database. These two threads also do not have write permission. Each thread has its own connection to the database file, and I am not using a critical section to control access, since all three threads should have no trouble reading from the database at the same time.

Yet it locks up, as if I had called CriticalSection.Enter on the main thread. Looking over the dump, it looks like the Xojo framework is handling its own mutex on the file. The main thread is waiting on something, but when the main thread waits, all code stops and the app locks up. I consider this a bug personally, but Xojo hasn’t fixed this in years, so it is what it is.

Anybody have any idea what could be going on?

Analysis of sampling Beacon (pid 82980) every 1 millisecond
Process:         Beacon [82980]
Path:            /Applications/Beacon.app/Contents/MacOS/Beacon
Load Address:    0x100418000
Identifier:      com.thezaz.beacon
Version:         1.6.2.2 (1.6.2.3.2)
Code Type:       ARM64
Platform:        macOS
Parent Process:  ??? [1]

Date/Time:       2023-01-05 12:54:41.905 -0500
Launch Time:     2023-01-05 10:55:16.794 -0500
OS Version:      macOS 13.1 (22C65)
Report Version:  7
Analysis Tool:   /usr/bin/sample

Physical footprint:         317.9M
Physical footprint (peak):  318.5M
Idle exit: untracked
----

Call graph:
    2557 Thread_9139805   DispatchQueue_1: com.apple.main-thread  (serial)
    + 2557 start  (in dyld) + 2544  [0x1a61ebe50]
    +   2557 main  (in Beacon) + 20  [0x103e8eae8]
    +     2557 _Main  (in Beacon) + 384  [0x103e97b0c]
    +       2557 REALbasic._RuntimeRun  (in Beacon) + 28  [0x100739804]
    +         2557 RuntimeRun  (in XojoFramework) + 48  [0x1058f1c30]
    +           2557 -[NSApplication run]  (in AppKit) + 464  [0x1a98679e4]
    +             2557 ???  (in XojoFramework)  load address 0x105684000 + 0xe5214  [0x105769214]
    +               2557 CallFunctionWithExceptionHandling(void (*)())  (in XojoFramework) + 180  [0x1058f33d4]
    +                 2557 Application._CallFunctionWithExceptionHandling%%o<Application>p  (in Beacon) + 164  [0x100656fd0]
    +                   2557 ???  (in XojoFramework)  load address 0x105684000 + 0xe5278  [0x105769278]
    +                     2557 ???  (in XojoFramework)  load address 0x105684000 + 0xe51f0  [0x1057691f0]
    +                       2557 -[NSApplication(NSEvent) _nextEventMatchingEventMask:untilDate:inMode:dequeue:]  (in AppKit) + 728  [0x1a98735b4]
    +                         2557 _DPSNextEvent  (in AppKit) + 632  [0x1a9874424]
    +                           2557 _BlockUntilNextEventMatchingListInModeWithFilter  (in HIToolbox) + 72  [0x1afcc7b2c]
    +                             2557 ReceiveNextEventCommon  (in HIToolbox) + 672  [0x1afcc7de4]
    +                               2557 RunCurrentEventLoopInMode  (in HIToolbox) + 292  [0x1afcc7fa0]
    +                                 2557 CFRunLoopRunSpecific  (in CoreFoundation) + 612  [0x1a65f2888]
    +                                   2557 __CFRunLoopRun  (in CoreFoundation) + 1896  [0x1a65f3744]
    +                                     2557 __CFRunLoopDoTimers  (in CoreFoundation) + 356  [0x1a660dd5c]
    +                                       2557 __CFRunLoopDoTimer  (in CoreFoundation) + 940  [0x1a660e204]
    +                                         2557 __CFRUNLOOP_IS_CALLING_OUT_TO_A_TIMER_CALLBACK_FUNCTION__  (in CoreFoundation) + 32  [0x1a660e55c]
    +                                           2557 ???  (in XojoFramework)  load address 0x105684000 + 0xe5b38  [0x105769b38]
    +                                             2557 ???  (in XojoFramework)  load address 0x105684000 + 0x27d1b8  [0x1059011b8]
    +                                               2557 ???  (in XojoFramework)  load address 0x105684000 + 0x27f5a8  [0x1059035a8]
    +                                                 2557 xojo::ConditionVariable::Wait(xojo::UniqueLock&)  (in XojoFramework) + 20  [0x1057c29e0]
    +                                                   2557 _pthread_cond_wait  (in libsystem_pthread.dylib) + 1232  [0x1a6515638]
    +                                                     2557 __psynch_cvwait  (in libsystem_kernel.dylib) + 8  [0x1a64d9564]
    2557 Thread_9139864: com.apple.NSURLConnectionLoader
    + 2557 thread_start  (in libsystem_pthread.dylib) + 8  [0x1a650fe2c]
    +   2557 _pthread_start  (in libsystem_pthread.dylib) + 148  [0x1a651506c]
    +     2557 __NSThread__start__  (in Foundation) + 716  [0x1a74f5470]
    +       2557 ???  (in CFNetwork)  load address 0x1aad99000 + 0x253500  [0x1aafec500]
    +         2557 CFRunLoopRunSpecific  (in CoreFoundation) + 612  [0x1a65f2888]
    +           2557 __CFRunLoopRun  (in CoreFoundation) + 1232  [0x1a65f34ac]
    +             2557 __CFRunLoopServiceMachPort  (in CoreFoundation) + 160  [0x1a65f4bc0]
    +               2557 mach_msg  (in libsystem_kernel.dylib) + 24  [0x1a64d60ec]
    +                 2557 mach_msg_overwrite  (in libsystem_kernel.dylib) + 540  [0x1a64de5c4]
    +                   2557 mach_msg2_internal  (in libsystem_kernel.dylib) + 80  [0x1a64e78a4]
    +                     2557 mach_msg2_trap  (in libsystem_kernel.dylib) + 8  [0x1a64d5d70]
    2557 Thread_9139874: com.apple.NSEventThread
    + 2557 thread_start  (in libsystem_pthread.dylib) + 8  [0x1a650fe2c]
    +   2557 _pthread_start  (in libsystem_pthread.dylib) + 148  [0x1a651506c]
    +     2557 _NSEventThread  (in AppKit) + 172  [0x1a999e410]
    +       2557 CFRunLoopRunSpecific  (in CoreFoundation) + 612  [0x1a65f2888]
    +         2541 __CFRunLoopRun  (in CoreFoundation) + 1232  [0x1a65f34ac]
    +         ! 2541 __CFRunLoopServiceMachPort  (in CoreFoundation) + 160  [0x1a65f4bc0]
    +         !   2541 mach_msg  (in libsystem_kernel.dylib) + 24  [0x1a64d60ec]
    +         !     2541 mach_msg_overwrite  (in libsystem_kernel.dylib) + 540  [0x1a64de5c4]
    +         !       2541 mach_msg2_internal  (in libsystem_kernel.dylib) + 80  [0x1a64e78a4]
    +         !         2541 mach_msg2_trap  (in libsystem_kernel.dylib) + 8  [0x1a64d5d70]
    +         16 __CFRunLoopRun  (in CoreFoundation) + 2264  [0x1a65f38b4]
    +           16 __CFRunLoopDoSource1  (in CoreFoundation) + 520  [0x1a65f4ec8]
    +             16 __CFRUNLOOP_IS_CALLING_OUT_TO_A_SOURCE1_PERFORM_FUNCTION__  (in CoreFoundation) + 60  [0x1a65f4fa8]
    +               16 __CFMachPortPerform  (in CoreFoundation) + 260  [0x1a6624420]
    +                 16 MessageHandler(__CFMachPort*, void*, long, void*)  (in HIToolbox) + 60  [0x1afcd4ae0]
    +                   11 PullEventsFromWindowServerOnConnection(unsigned int, unsigned char, __CFMachPortBoost*)  (in HIToolbox) + 60  [0x1afcd4b58]
    +                   : 11 SLEventCreateNextEvent  (in SkyLight) + 16  [0x1ab3445a4]
    +                   :   11 SLSGetNextEventRecordInternal  (in SkyLight) + 344  [0x1ab542a8c]
    +                   :     9 CGSSnarfAndDispatchDatagrams  (in SkyLight) + 160  [0x1ab21ae50]
    +                   :     | 9 mach_msg  (in libsystem_kernel.dylib) + 24  [0x1a64d60ec]
    +                   :     |   9 mach_msg_overwrite  (in libsystem_kernel.dylib) + 540  [0x1a64de5c4]
    +                   :     |     9 mach_msg2_internal  (in libsystem_kernel.dylib) + 80  [0x1a64e78a4]
    +                   :     |       9 mach_msg2_trap  (in libsystem_kernel.dylib) + 8  [0x1a64d5d70]
    +                   :     2 CGSSnarfAndDispatchDatagrams  (in SkyLight) + 808  [0x1ab21b0d8]
    +                   :       2 event_datagram_handler(unsigned int, CGSDatagramType, void*, unsigned long, void*)  (in SkyLight) + 92  [0x1ab542164]
    +                   :         2 CGSDecodeEventRecord  (in SkyLight) + 56  [0x1ab21b8ec]
    +                   :           2 SLEventRecordCreateWithBytesAndSource(void const*, unsigned long, __CGEventSource*)  (in SkyLight) + 496  [0x1ab344944]
    +                   :             2 SLEventGetFieldDecodeDescriptor(SLEventToken)::$_18::__invoke(SLSEventRecord*, SLEventToken, SLEventData&)  (in SkyLight) + 84  [0x1ab3450f4]
    +                   :               2 IOHIDEventCreateWithBytes  (in IOKit) + 344  [0x1a97054c0]
    +                   :                 2 IOHIDEventAppendEvent  (in IOKit) + 60  [0x1a971117c]
    +                   :                   1 CFArrayCreateMutable  (in CoreFoundation) + 140  [0x1a6590440]
    +                   :                   + 1 CFArrayCreateMutable  (in CoreFoundation) + 176  [0x1a6590464]
    +                   :                   1 CFArrayCreateMutable  (in CoreFoundation) + 188  [0x1a6590470]
    +                   :                     1 objc_msgSend  (in libobjc.A.dylib) + 64  [0x1a61a9840]
    +                   5 PullEventsFromWindowServerOnConnection(unsigned int, unsigned char, __CFMachPortBoost*)  (in HIToolbox) + 312  [0x1afcd4c54]
    +                     5 SLEventCreateNextEvent  (in SkyLight) + 16  [0x1ab3445a4]
    +                       5 SLSGetNextEventRecordInternal  (in SkyLight) + 344  [0x1ab542a8c]
    +                         5 CGSSnarfAndDispatchDatagrams  (in SkyLight) + 160  [0x1ab21ae50]
    +                           5 mach_msg  (in libsystem_kernel.dylib) + 24  [0x1a64d60ec]
    +                             5 mach_msg_overwrite  (in libsystem_kernel.dylib) + 540  [0x1a64de5c4]
    +                               5 mach_msg2_internal  (in libsystem_kernel.dylib) + 80  [0x1a64e78a4]
    +                                 5 mach_msg2_trap  (in libsystem_kernel.dylib) + 8  [0x1a64d5d70]
    2557 Thread_9139912
    + 2557 thread_start  (in libsystem_pthread.dylib) + 8  [0x1a650fe2c]
    +   2557 _pthread_start  (in libsystem_pthread.dylib) + 148  [0x1a651506c]
    +     2557 ???  (in XojoFramework)  load address 0x105684000 + 0x13e6c4  [0x1057c26c4]
    +       2557 ???  (in XojoFramework)  load address 0x105684000 + 0x27e6d4  [0x1059026d4]
    +         2557 AnimationKit.Coordinator.ThreadedAnimator_Run%%o<AnimationKit.Coordinator>o<Thread>  (in Beacon) + 420  [0x101ec6b74]
    +           2557 Thread.Pause%%o<Thread>  (in Beacon) + 16  [0x100643e10]
    +             2557 ???  (in XojoFramework)  load address 0x105684000 + 0x27d1b8  [0x1059011b8]
    +               2557 ???  (in XojoFramework)  load address 0x105684000 + 0x27f5a8  [0x1059035a8]
    +                 2557 xojo::ConditionVariable::Wait(xojo::UniqueLock&)  (in XojoFramework) + 20  [0x1057c29e0]
    +                   2557 _pthread_cond_wait  (in libsystem_pthread.dylib) + 1232  [0x1a6515638]
    +                     2557 __psynch_cvwait  (in libsystem_kernel.dylib) + 8  [0x1a64d9564]
    2557 Thread_9222867
    + 2557 thread_start  (in libsystem_pthread.dylib) + 8  [0x1a650fe2c]
    +   2557 _pthread_start  (in libsystem_pthread.dylib) + 148  [0x1a651506c]
    +     2557 ???  (in XojoFramework)  load address 0x105684000 + 0x13e6c4  [0x1057c26c4]
    +       2557 ???  (in XojoFramework)  load address 0x105684000 + 0x27e6d4  [0x1059026d4]
    +         2557 Beacon.Thread.Event_Run%%o<Beacon.Thread>  (in Beacon) + 128  [0x100ba5078]
    +           2557 Ark.ImportThread.Event_Run%%o<Ark.ImportThread>  (in Beacon) + 23324  [0x101a760a4]
    +             2557 Ark.ImportThread.Import%v%o<Ark.ImportThread>s  (in Beacon) + 776  [0x101aa6dd4]
    +               2557 Ark.ImportThread.!ToXojoType%v%v  (in Beacon) + 9052  [0x101aaa234]
    +                 2557 Ark.ImportThread.!ToXojoType%v%v  (in Beacon) + 10380  [0x101aaa764]
    +                   2557 Ark.ImportThread.!ToXojoType%v%v  (in Beacon) + 7904  [0x101aa9db8]
    +                     2557 Ark.ImportThread.!ToXojoType%v%v  (in Beacon) + 10380  [0x101aaa764]
    +                       2557 Ark.ImportThread.!ToXojoType%v%v  (in Beacon) + 7904  [0x101aa9db8]
    +                         2557 Ark.ImportThread.!ToXojoType%v%v  (in Beacon) + 10488  [0x101aaa7d0]
    +                           2557 RuntimeBackgroundTask  (in XojoFramework) + 40  [0x1057f6fc4]
    +                             2557 ???  (in XojoFramework)  load address 0x105684000 + 0x27d1b8  [0x1059011b8]
    +                               2557 ???  (in XojoFramework)  load address 0x105684000 + 0x27f5a8  [0x1059035a8]
    +                                 2557 xojo::ConditionVariable::Wait(xojo::UniqueLock&)  (in XojoFramework) + 20  [0x1057c29e0]
    +                                   2557 _pthread_cond_wait  (in libsystem_pthread.dylib) + 1232  [0x1a6515638]
    +                                     2557 __psynch_cvwait  (in libsystem_kernel.dylib) + 8  [0x1a64d9564]
    2557 Thread_9222868
    + 2557 thread_start  (in libsystem_pthread.dylib) + 8  [0x1a650fe2c]
    +   2557 _pthread_start  (in libsystem_pthread.dylib) + 148  [0x1a651506c]
    +     2557 ???  (in XojoFramework)  load address 0x105684000 + 0x13e6c4  [0x1057c26c4]
    +       2557 ???  (in XojoFramework)  load address 0x105684000 + 0x27e6d4  [0x1059026d4]
    +         2557 Beacon.Thread.Event_Run%%o<Beacon.Thread>  (in Beacon) + 128  [0x100ba5078]
    +           2557 Ark.ImportThread.Event_Run%%o<Ark.ImportThread>  (in Beacon) + 59520  [0x101a7ee08]
    +             2557 Ark.ImportThread.BuildProject%o<Ark.Project>%o<Ark.ImportThread>o<Dictionary>o<Dictionary>  (in Beacon) + 119040  [0x101a9cb14]
    +               2557 Ark.Configs.CreateInstance%o<Ark.ConfigGroup>%so<Dictionary>o<Dictionary>o<Ark.Project>  (in Beacon) + 5028  [0x100de5e8c]
    +                 2557 Ark.Configs.LootDrops.!FromImport%o<Ark.Configs.LootDrops>%o<Dictionary>o<Dictionary>u8f8o<Beacon.StringList>  (in Beacon) + 4804  [0x100eddd48]
    +                   2557 Ark.LootContainer.!ImportFromConfig%o<Ark.LootContainer>%o<Dictionary>f8o<Beacon.StringList>  (in Beacon) + 43924  [0x1011b5f60]
    +                     2557 Ark.LootItemSet.!ImportFromConfig%o<Ark.LootItemSet>%o<Dictionary>o<Beacon.Range>f8o<Beacon.StringList>  (in Beacon) + 9804  [0x10170cf48]
    +                       2557 Ark.LootItemSetEntry.!ImportFromConfig%o<Ark.LootItemSetEntry>%o<Dictionary>o<Beacon.Range>f8o<Beacon.StringList>  (in Beacon) + 45132  [0x10174ae20]
    +                         2557 Ark.ResolveEngram%o<Ark.Engram>%ssso<Beacon.StringList>  (in Beacon) + 1940  [0x100d9e758]
    +                           2557 Ark.DataSource.GetEngramsByClass%A1o<Ark.Engram>%o<Ark.DataSource>so<Beacon.StringList>  (in Beacon) + 924  [0x10159978c]
    +                             2557 Beacon.DataSource.*SQLSelect%o<RowSet>%o<Beacon.DataSource>sA1v  (in Beacon) + 536  [0x100c59a50]
    +                               2557 Database.SelectSQL%o<RowSet>%o<Database>sA1v  (in Beacon) + 64  [0x100494e08]
    +                                 2557 DatabaseSelectSQL  (in XojoFramework) + 72  [0x105809d6c]
    +                                   2557 ???  (in SQLiteDatabase.dylib)  load address 0x1092fc000 + 0x6814  [0x109302814]
    +                                     2557 ???  (in SQLiteDatabase.dylib)  load address 0x1092fc000 + 0xe8b0  [0x10930a8b0]
    +                                       2557 ???  (in SQLiteDatabase.dylib)  load address 0x1092fc000 + 0x9d48  [0x109305d48]
    +                                         2557 ???  (in SQLiteDatabase.dylib)  load address 0x1092fc000 + 0x1da0c  [0x109319a0c]
    +                                           2557 _pthread_mutex_firstfit_lock_slow  (in libsystem_pthread.dylib) + 248  [0x1a650fa9c]
    +                                             2557 _pthread_mutex_firstfit_lock_wait  (in libsystem_pthread.dylib) + 84  [0x1a6512144]
    +                                               2557 __psynch_mutexwait  (in libsystem_kernel.dylib) + 8  [0x1a64d8a1c]
    2557 Thread_9222870
    + 2557 thread_start  (in libsystem_pthread.dylib) + 8  [0x1a650fe2c]
    +   2557 _pthread_start  (in libsystem_pthread.dylib) + 148  [0x1a651506c]
    +     2557 ???  (in XojoFramework)  load address 0x105684000 + 0x13e6c4  [0x1057c26c4]
    +       2557 ???  (in XojoFramework)  load address 0x105684000 + 0x27e6d4  [0x1059026d4]
    +         2557 Beacon.Thread.Event_Run%%o<Beacon.Thread>  (in Beacon) + 128  [0x100ba5078]
    +           2557 Ark.ImportThread.Event_Run%%o<Ark.ImportThread>  (in Beacon) + 59520  [0x101a7ee08]
    +             2557 Ark.ImportThread.BuildProject%o<Ark.Project>%o<Ark.ImportThread>o<Dictionary>o<Dictionary>  (in Beacon) + 119040  [0x101a9cb14]
    +               2557 Ark.Configs.CreateInstance%o<Ark.ConfigGroup>%so<Dictionary>o<Dictionary>o<Ark.Project>  (in Beacon) + 5028  [0x100de5e8c]
    +                 2557 Ark.Configs.LootDrops.!FromImport%o<Ark.Configs.LootDrops>%o<Dictionary>o<Dictionary>u8f8o<Beacon.StringList>  (in Beacon) + 4804  [0x100eddd48]
    +                   2557 Ark.LootContainer.!ImportFromConfig%o<Ark.LootContainer>%o<Dictionary>f8o<Beacon.StringList>  (in Beacon) + 43924  [0x1011b5f60]
    +                     2557 Ark.LootItemSet.!ImportFromConfig%o<Ark.LootItemSet>%o<Dictionary>o<Beacon.Range>f8o<Beacon.StringList>  (in Beacon) + 9804  [0x10170cf48]
    +                       2557 Ark.LootItemSetEntry.!ImportFromConfig%o<Ark.LootItemSetEntry>%o<Dictionary>o<Beacon.Range>f8o<Beacon.StringList>  (in Beacon) + 45132  [0x10174ae20]
    +                         2557 Ark.ResolveEngram%o<Ark.Engram>%ssso<Beacon.StringList>  (in Beacon) + 1940  [0x100d9e758]
    +                           2557 Ark.DataSource.GetEngramsByClass%A1o<Ark.Engram>%o<Ark.DataSource>so<Beacon.StringList>  (in Beacon) + 924  [0x10159978c]
    +                             2557 Beacon.DataSource.*SQLSelect%o<RowSet>%o<Beacon.DataSource>sA1v  (in Beacon) + 536  [0x100c59a50]
    +                               2557 Database.SelectSQL%o<RowSet>%o<Database>sA1v  (in Beacon) + 64  [0x100494e08]
    +                                 2557 DatabaseSelectSQL  (in XojoFramework) + 72  [0x105809d6c]
    +                                   2557 ???  (in SQLiteDatabase.dylib)  load address 0x1092fc000 + 0x6814  [0x109302814]
    +                                     2557 ???  (in SQLiteDatabase.dylib)  load address 0x1092fc000 + 0xf0f0  [0x10930b0f0]
    +                                       2557 ???  (in SQLiteDatabase.dylib)  load address 0x1092fc000 + 0x925c  [0x10930525c]
    +                                         2557 ???  (in SQLiteDatabase.dylib)  load address 0x1092fc000 + 0x15b1c  [0x109311b1c]
    +                                           2557 ???  (in SQLiteDatabase.dylib)  load address 0x1092fc000 + 0x42304  [0x10933e304]
    +                                             2557 ???  (in SQLiteDatabase.dylib)  load address 0x1092fc000 + 0xa458  [0x109306458]
    +                                               2557 RuntimeBackgroundTask  (in XojoFramework) + 40  [0x1057f6fc4]
    +                                                 2557 ???  (in XojoFramework)  load address 0x105684000 + 0x27d1b8  [0x1059011b8]
    +                                                   2557 ???  (in XojoFramework)  load address 0x105684000 + 0x27f5a8  [0x1059035a8]
    +                                                     2557 xojo::ConditionVariable::Wait(xojo::UniqueLock&)  (in XojoFramework) + 20  [0x1057c29e0]
    +                                                       2557 _pthread_cond_wait  (in libsystem_pthread.dylib) + 1232  [0x1a6515638]
    +                                                         2557 __psynch_cvwait  (in libsystem_kernel.dylib) + 8  [0x1a64d9564]
    2557 Thread_9223047
      2557 start_wqthread  (in libsystem_pthread.dylib) + 8  [0x1a650fe20]
        2557 _pthread_wqthread  (in libsystem_pthread.dylib) + 364  [0x1a651114c]
          2557 __workq_kernreturn  (in libsystem_kernel.dylib) + 8  [0x1a64d7a1c]

Total number in stack (recursive counted multiple, when >=5):
        6       _pthread_start  (in libsystem_pthread.dylib) + 148  [0x1a651506c]
        6       thread_start  (in libsystem_pthread.dylib) + 8  [0x1a650fe2c]

Sort by top of stack, same collapsed (when >= 5):
        __psynch_cvwait  (in libsystem_kernel.dylib)        10228
        mach_msg2_trap  (in libsystem_kernel.dylib)        5112
        __psynch_mutexwait  (in libsystem_kernel.dylib)        2557
        __workq_kernreturn  (in libsystem_kernel.dylib)        2557
2

You set WriteAheadLogging to True and ThreadYieldInterval to some non-zero value on the SQLiteDatabase?

3

Also use different connections for each virtual “parallel user” (thread).

4

Yes, though I’m turning on WAL with Self.mDatabase.ExecuteSQL("PRAGMA journal_mode = WAL;"). Do you think maybe setting WriteAheadLogging to false turns off some kind of lock management?

5

None of my databases runs with WAL. I implement my own backoff/retry although thanks to recent comments I do have ThreadYieldInterval set to some non-zero value on any connection. Seems to work reasonably well.

But I’m still hoping for some action on:

https://tracker.xojo.com/xojoinc/xojo/-/issues/71272

6

I’d think that using the property instead might trigger other functionality that direct use of the PRAGMA bypasses. Can you try just the property to be sure?

(I’m just throwing out ideas since I have no extensive experience with SQLite, and the old Multiuser property used to do the job for my simple cases.)

7

This is a pessimistic approach. WAL enabled your can get multiple “parallel reads” with almost no delay. No wait times.

8

Decent idea, and I’m going to keep the code change, but it made no difference. It still locks up if I try two selects on the same database file at the same time.

9

I may play around with that now that the latest update to my app is released.

10

Might be time to look into MBS SQLite…

11

“Locks up” you mean as in one connection will get SQLITE busy? Set a connection timeout of 1 sec.

12

No, I mean the app stops responding. Infinite loop. The main thread tries to fire timer events, hits some sort of wait condition, and that’s where everything stops. If you wait on the main thread, your app dies.

13

ThreadYieldInterval helps here. Set it to a few hundred for each connection. And see the Issue I referenced above.

14

Yeah, I have it set to 75.

15

Are you using any #pragma BackgroundTasks in your code?

16

Rarely. I think in one spot I’ve turned them off on the main thread, basically as a poor man’s lock.

17

I think I’ve figured it out. I’m not actually getting a new SQLiteDatabase instance / connection per thread as I intended. So all three are using the same instance. That’ll do it.

1 Like
18

Tilt !!

19

Good news.

20

I wish I had seen this before I set up a test project. :slight_smile:

Glad you got it solved.