Well, that issue is really hard to debug for me.
In the nextcloud log file, the filenames are truncated and the output of the occ command does not contain any filename or date/time information. So itās impossible to find any useful information for debugging.
Here is a typical output of the occ command, which was crashed after about 15 minutes.
sudo -u web12 php occ preview:generate-all -vvv
**** Error: Cannot find a 'startxref' anywhere in the file.
**** Warning: An error occurred while reading an XREF table.
**** The file has been damaged. This may have been caused
**** by a problem while converting or transfering the file.
**** Ghostscript will attempt to recover the data.
**** Error: Trailer is not found.
Requested FirstPage is greater than the number of pages in the file: 0
No pages will be processed (FirstPage > LastPage).
**** This file had errors that were repaired or ignored.
**** Please notify the author of the software that produced this
**** file that it does not conform to Adobe's published PDF
**** specification.
**** Error: Cannot find a 'startxref' anywhere in the file.
**** Warning: An error occurred while reading an XREF table.
**** The file has been damaged. This may have been caused
**** by a problem while converting or transfering the file.
**** Ghostscript will attempt to recover the data.
**** Error: Trailer is not found.
Requested FirstPage is greater than the number of pages in the file: 0
No pages will be processed (FirstPage > LastPage).
**** This file had errors that were repaired or ignored.
**** Please notify the author of the software that produced this
**** file that it does not conform to Adobe's published PDF
**** specification.
Getƶtet
Note the last line - it means killed.
The last 5 lines of nextcloud.log before the occ comand crashes:
{"reqId":"H59fJJ+USGx7MaHFmW6g","remoteAddr":"","app":"no app in context","message":"Exception: {\"Exception\":\"OC\\\\User\\\\NoUserException\",\"Message\":\"Backends provided no user object\",\"Code\":0,\"Trace\":\"#0 [internal function]: OC\\\\Files\\\\Node\\\\Root->getUserFolder(NULL)\\n#1 \\\/var\\\/www\\\/clients\\\/client3\\\/web12\\\/web\\\/lib\\\/private\\\/Files\\\/Node\\\/LazyRoot.php(65): call_user_func_array(Array, Array)\\n#2 \\\/var\\\/www\\\/clients\\\/client3\\\/web12\\\/web\\\/lib\\\/private\\\/Files\\\/Node\\\/LazyRoot.php(282): OC\\\\Files\\\\Node\\\\LazyRoot->__call('getUserFolder', Array)\\n#3 \\\/var\\\/www\\\/clients\\\/client3\\\/web12\\\/web\\\/apps\\\/files_downloadactivity\\\/lib\\\/Activity\\\/Listener.php(141): OC\\\\Files\\\\Node\\\\LazyRoot->getUserFolder(NULL)\\n#4 \\\/var\\\/www\\\/clients\\\/client3\\\/web12\\\/web\\\/apps\\\/files_downloadactivity\\\/lib\\\/Activity\\\/Listener.php(77): OCA\\\\FilesDownloadActivity\\\\Activity\\\\Listener->getSourcePathAndOwner('\\\/var\\\/www\\\/client...')\\n#5 \\\/var\\\/www\\\/clients\\\/client3\\\/web12\\\/web\\\/apps\\\/files_downloadactivity\\\/lib\\\/AppInfo\\\/Application.php(47): OCA\\\\FilesDownloadActivity\\\\Activity\\\\Listener->readFile('\\\/var\\\/www\\\/client...')\\n#6 \\\/var\\\/www\\\/clients\\\/client3\\\/web12\\\/web\\\/lib\\\/private\\\/legacy\\\/hook.php(106): OCA\\\\FilesDownloadActivity\\\\AppInfo\\\\Application->listenReadFile(Array)\\n#7 \\\/var\\\/www\\\/clients\\\/client3\\\/web12\\\/web\\\/lib\\\/private\\\/Files\\\/View.php(1243): OC_Hook::emit('OC_Filesystem', 'read', Array)\\n#8 \\\/var\\\/www\\\/clients\\\/client3\\\/web12\\\/web\\\/lib\\\/private\\\/Files\\\/View.php(1113): OC\\\\Files\\\\View->runHooks(Array, '\\\/var\\\/www\\\/client...')\\n#9 \\\/var\\\/www\\\/clients\\\/client3\\\/web12\\\/web\\\/lib\\\/private\\\/Files\\\/View.php(577): OC\\\\Files\\\\View->basicOperation('file_get_conten...', '\\\/var\\\/www\\\/client...', Array)\\n#10 \\\/var\\\/www\\\/clients\\\/client3\\\/web12\\\/web\\\/lib\\\/private\\\/Files\\\/Filesystem.php(719): OC\\\\Files\\\\View->file_get_contents('\\\/var\\\/www\\\/client...')\\n#11 \\\/var\\\/www\\\/clients\\\/client3\\\/web12\\\/web\\\/lib\\\/private\\\/legacy\\\/image.php(597): OC\\\\Files\\\\Filesystem::file_get_contents('\\\/var\\\/www\\\/client...')\\n#12 \\\/var\\\/www\\\/clients\\\/client3\\\/web12\\\/web\\\/lib\\\/private\\\/Preview\\\/MP3.php(80): OC_Image->loadFromFile('\\\/var\\\/www\\\/client...')\\n#13 \\\/var\\\/www\\\/clients\\\/client3\\\/web12\\\/web\\\/lib\\\/private\\\/Preview\\\/MP3.php(64): OC\\\\Preview\\\\MP3->getNoCoverThumbnail()\\n#14 \\\/var\\\/www\\\/clients\\\/client3\\\/web12\\\/web\\\/lib\\\/private\\\/Preview\\\/GeneratorHelper.php(54): OC\\\\Preview\\\\MP3->getThumbnail('\\\/files\\\/Archiv\\\/K...', 2048, 2048, false, Object(OC\\\\Files\\\\View))\\n#15 \\\/var\\\/www\\\/clients\\\/client3\\\/web12\\\/web\\\/lib\\\/private\\\/Preview\\\/Generator.php(155): OC\\\\Preview\\\\GeneratorHelper->getThumbnail(Object(OC\\\\Preview\\\\MP3), Object(OC\\\\Files\\\\Node\\\\File), 2048, 2048)\\n#16 \\\/var\\\/www\\\/clients\\\/client3\\\/web12\\\/web\\\/lib\\\/private\\\/Preview\\\/Generator.php(108): OC\\\\Preview\\\\Generator->getMaxPreview(Object(OC\\\\Files\\\\SimpleFS\\\\SimpleFolder), Object(OC\\\\Files\\\\Node\\\\File), 'audio\\\/mpeg')\\n#17 \\\/var\\\/www\\\/clients\\\/client3\\\/web12\\\/web\\\/lib\\\/private\\\/PreviewManager.php(182): OC\\\\Preview\\\\Generator->getPreview(Object(OC\\\\Files\\\\Node\\\\File), 32, 32, true, 'fill', 'audio\\\/mpeg')\\n#18 \\\/var\\\/www\\\/clients\\\/client3\\\/web12\\\/web\\\/apps\\\/previewgenerator\\\/lib\\\/Command\\\/Generate.php(167): OC\\\\PreviewManager->getPreview(Object(OC\\\\Files\\\\Node\\\\File), 32, 32, true)\\n#19 \\\/var\\\/www\\\/clients\\\/client3\\\/web12\\\/web\\\/apps\\\/previewgenerator\\\/lib\\\/Command\\\/Generate.php(155): OCA\\\\PreviewGenerator\\\\Command\\\\Generate->parseFile(Object(OC\\\\Files\\\\Node\\\\File))\\n#20 \\\/var\\\/www\\\/clients\\\/client3\\\/web12\\\/web\\\/apps\\\/previewgenerator\\\/lib\\\/Command\\\/Generate.php(153): OCA\\\\PreviewGenerator\\\\Command\\\\Generate->parseFolder(Object(OC\\\\Files\\\\Node\\\\Folder))\\n#21 \\\/var\\\/www\\\/clients\\\/client3\\\/web12\\\/web\\\/apps\\\/previewgenerator\\\/lib\\\/Command\\\/Generate.php(153): OCA\\\\PreviewGenerator\\\\Command\\\\Generate->parseFolder(Object(OC\\\\Files\\\\Node\\\\Folder))\\n#22 \\\/var\\\/www\\\/clients\\\/client3\\\/web12\\\/web\\\/apps\\\/previewgenerator\\\/lib\\\/Command\\\/Generate.php(153): OCA\\\\PreviewGenerator\\\\Command\\\\Generate->parseFolder(Object(OC\\\\Files\\\\Node\\\\Folder))\\n#23 \\\/var\\\/www\\\/clients\\\/client3\\\/web12\\\/web\\\/apps\\\/previewgenerator\\\/lib\\\/Command\\\/Generate.php(153): OCA\\\\PreviewGenerator\\\\Command\\\\Generate->parseFolder(Object(OC\\\\Files\\\\Node\\\\Folder))\\n#24 \\\/var\\\/www\\\/clients\\\/client3\\\/web12\\\/web\\\/apps\\\/previewgenerator\\\/lib\\\/Command\\\/Generate.php(153): OCA\\\\PreviewGenerator\\\\Command\\\\Generate->parseFolder(Object(OC\\\\Files\\\\Node\\\\Folder))\\n#25 \\\/var\\\/www\\\/clients\\\/client3\\\/web12\\\/web\\\/apps\\\/previewgenerator\\\/lib\\\/Command\\\/Generate.php(142): OCA\\\\PreviewGenerator\\\\Command\\\\Generate->parseFolder(Object(OC\\\\Files\\\\Node\\\\Folder))\\n#26 \\\/var\\\/www\\\/clients\\\/client3\\\/web12\\\/web\\\/apps\\\/previewgenerator\\\/lib\\\/Command\\\/Generate.php(96): OCA\\\\PreviewGenerator\\\\Command\\\\Generate->generateUserPreviews(Object(OC\\\\User\\\\User))\\n#27 \\\/var\\\/www\\\/clients\\\/client3\\\/web12\\\/web\\\/lib\\\/private\\\/User\\\/Manager.php(410): OCA\\\\PreviewGenerator\\\\Command\\\\Generate->OCA\\\\PreviewGenerator\\\\Command\\\\{closure}(Object(OC\\\\User\\\\User))\\n#28 \\\/var\\\/www\\\/clients\\\/client3\\\/web12\\\/web\\\/apps\\\/previewgenerator\\\/lib\\\/Command\\\/Generate.php(97): OC\\\\User\\\\Manager->callForSeenUsers(Object(Closure))\\n#29 \\\/var\\\/www\\\/clients\\\/client3\\\/web12\\\/web\\\/3rdparty\\\/symfony\\\/console\\\/Command\\\/Command.php(256): OCA\\\\PreviewGenerator\\\\Command\\\\Generate->execute(Object(Symfony\\\\Component\\\\Console\\\\Input\\\\ArgvInput), Object(Symfony\\\\Component\\\\Console\\\\Output\\\\ConsoleOutput))\\n#30 \\\/var\\\/www\\\/clients\\\/client3\\\/web12\\\/web\\\/3rdparty\\\/symfony\\\/console\\\/Application.php(818): Symfony\\\\Component\\\\Console\\\\Command\\\\Command->run(Object(Symfony\\\\Component\\\\Console\\\\Input\\\\ArgvInput), Object(Symfony\\\\Component\\\\Console\\\\Output\\\\ConsoleOutput))\\n#31 \\\/var\\\/www\\\/clients\\\/client3\\\/web12\\\/web\\\/3rdparty\\\/symfony\\\/console\\\/Application.php(186): Symfony\\\\Component\\\\Console\\\\Application->doRunCommand(Object(OCA\\\\PreviewGenerator\\\\Command\\\\Generate), Object(Symfony\\\\Component\\\\Console\\\\Input\\\\ArgvInput), Object(Symfony\\\\Component\\\\Console\\\\Output\\\\ConsoleOutput))\\n#32 \\\/var\\\/www\\\/clients\\\/client3\\\/web12\\\/web\\\/3rdparty\\\/symfony\\\/console\\\/Application.php(117): Symfony\\\\Component\\\\Console\\\\Application->doRun(Object(Symfony\\\\Component\\\\Console\\\\Input\\\\ArgvInput), Object(Symfony\\\\Component\\\\Console\\\\Output\\\\ConsoleOutput))\\n#33 \\\/var\\\/www\\\/clients\\\/client3\\\/web12\\\/web\\\/lib\\\/private\\\/Console\\\/Application.php(169): Symfony\\\\Component\\\\Console\\\\Application->run(Object(Symfony\\\\Component\\\\Console\\\\Input\\\\ArgvInput), Object(Symfony\\\\Component\\\\Console\\\\Output\\\\ConsoleOutput))\\n#34 \\\/var\\\/www\\\/clients\\\/client3\\\/web12\\\/web\\\/console.php(90): OC\\\\Console\\\\Application->run()\\n#35 \\\/var\\\/www\\\/clients\\\/client3\\\/web12\\\/web\\\/occ(11): require_once('\\\/var\\\/www\\\/client...')\\n#36 {main}\",\"File\":\"\\\/var\\\/www\\\/clients\\\/client3\\\/web12\\\/web\\\/lib\\\/private\\\/Files\\\/Node\\\/Root.php\",\"Line\":366}","level":3,"time":"2017-01-30T02:12:37+00:00","method":"--","url":"--","user":"--","version":"11.0.1.2"}
{"reqId":"H59fJJ+USGx7MaHFmW6g","remoteAddr":"","app":"files","message":"Backends provided no user object for ","level":3,"time":"2017-01-30T02:12:37+00:00","method":"--","url":"--","user":"--","version":"11.0.1.2"}
{"reqId":"H59fJJ+USGx7MaHFmW6g","remoteAddr":"","app":"no app in context","message":"Exception: {\"Exception\":\"OC\\\\User\\\\NoUserException\",\"Message\":\"Backends provided no user object\",\"Code\":0,\"Trace\":\"#0 [internal function]: OC\\\\Files\\\\Node\\\\Root->getUserFolder(NULL)\\n#1 \\\/var\\\/www\\\/clients\\\/client3\\\/web12\\\/web\\\/lib\\\/private\\\/Files\\\/Node\\\/LazyRoot.php(65): call_user_func_array(Array, Array)\\n#2 \\\/var\\\/www\\\/clients\\\/client3\\\/web12\\\/web\\\/lib\\\/private\\\/Files\\\/Node\\\/LazyRoot.php(282): OC\\\\Files\\\\Node\\\\LazyRoot->__call('getUserFolder', Array)\\n#3 \\\/var\\\/www\\\/clients\\\/client3\\\/web12\\\/web\\\/apps\\\/files_downloadactivity\\\/lib\\\/Activity\\\/Listener.php(141): OC\\\\Files\\\\Node\\\\LazyRoot->getUserFolder(NULL)\\n#4 \\\/var\\\/www\\\/clients\\\/client3\\\/web12\\\/web\\\/apps\\\/files_downloadactivity\\\/lib\\\/Activity\\\/Listener.php(77): OCA\\\\FilesDownloadActivity\\\\Activity\\\\Listener->getSourcePathAndOwner('\\\/Archiv\\\/Kamera-...')\\n#5 \\\/var\\\/www\\\/clients\\\/client3\\\/web12\\\/web\\\/apps\\\/files_downloadactivity\\\/lib\\\/AppInfo\\\/Application.php(47): OCA\\\\FilesDownloadActivity\\\\Activity\\\\Listener->readFile('\\\/Archiv\\\/Kamera-...')\\n#6 \\\/var\\\/www\\\/clients\\\/client3\\\/web12\\\/web\\\/lib\\\/private\\\/legacy\\\/hook.php(106): OCA\\\\FilesDownloadActivity\\\\AppInfo\\\\Application->listenReadFile(Array)\\n#7 \\\/var\\\/www\\\/clients\\\/client3\\\/web12\\\/web\\\/lib\\\/private\\\/Files\\\/View.php(1243): OC_Hook::emit('OC_Filesystem', 'read', Array)\\n#8 \\\/var\\\/www\\\/clients\\\/client3\\\/web12\\\/web\\\/lib\\\/private\\\/Files\\\/View.php(1113): OC\\\\Files\\\\View->runHooks(Array, '\\\/Archiv\\\/Kamera-...')\\n#9 \\\/var\\\/www\\\/clients\\\/client3\\\/web12\\\/web\\\/lib\\\/private\\\/Files\\\/View.php(967): OC\\\\Files\\\\View->basicOperation('fopen', '\\\/files\\\/Archiv\\\/K...', Array, 'r')\\n#10 \\\/var\\\/www\\\/clients\\\/client3\\\/web12\\\/web\\\/lib\\\/private\\\/Files\\\/View.php(978): OC\\\\Files\\\\View->fopen('\\\/files\\\/Archiv\\\/K...', 'r')\\n#11 \\\/var\\\/www\\\/clients\\\/client3\\\/web12\\\/web\\\/lib\\\/private\\\/Preview\\\/MP3.php(45): OC\\\\Files\\\\View->toTmpFile('\\\/files\\\/Archiv\\\/K...')\\n#12 \\\/var\\\/www\\\/clients\\\/client3\\\/web12\\\/web\\\/lib\\\/private\\\/Preview\\\/GeneratorHelper.php(54): OC\\\\Preview\\\\MP3->getThumbnail('\\\/files\\\/Archiv\\\/K...', 2048, 2048, false, Object(OC\\\\Files\\\\View))\\n#13 \\\/var\\\/www\\\/clients\\\/client3\\\/web12\\\/web\\\/lib\\\/private\\\/Preview\\\/Generator.php(155): OC\\\\Preview\\\\GeneratorHelper->getThumbnail(Object(OC\\\\Preview\\\\MP3), Object(OC\\\\Files\\\\Node\\\\File), 2048, 2048)\\n#14 \\\/var\\\/www\\\/clients\\\/client3\\\/web12\\\/web\\\/lib\\\/private\\\/Preview\\\/Generator.php(108): OC\\\\Preview\\\\Generator->getMaxPreview(Object(OC\\\\Files\\\\SimpleFS\\\\SimpleFolder), Object(OC\\\\Files\\\\Node\\\\File), 'audio\\\/mpeg')\\n#15 \\\/var\\\/www\\\/clients\\\/client3\\\/web12\\\/web\\\/lib\\\/private\\\/PreviewManager.php(182): OC\\\\Preview\\\\Generator->getPreview(Object(OC\\\\Files\\\\Node\\\\File), 32, 32, true, 'fill', 'audio\\\/mpeg')\\n#16 \\\/var\\\/www\\\/clients\\\/client3\\\/web12\\\/web\\\/apps\\\/previewgenerator\\\/lib\\\/Command\\\/Generate.php(167): OC\\\\PreviewManager->getPreview(Object(OC\\\\Files\\\\Node\\\\File), 32, 32, true)\\n#17 \\\/var\\\/www\\\/clients\\\/client3\\\/web12\\\/web\\\/apps\\\/previewgenerator\\\/lib\\\/Command\\\/Generate.php(155): OCA\\\\PreviewGenerator\\\\Command\\\\Generate->parseFile(Object(OC\\\\Files\\\\Node\\\\File))\\n#18 \\\/var\\\/www\\\/clients\\\/client3\\\/web12\\\/web\\\/apps\\\/previewgenerator\\\/lib\\\/Command\\\/Generate.php(153): OCA\\\\PreviewGenerator\\\\Command\\\\Generate->parseFolder(Object(OC\\\\Files\\\\Node\\\\Folder))\\n#19 \\\/var\\\/www\\\/clients\\\/client3\\\/web12\\\/web\\\/apps\\\/previewgenerator\\\/lib\\\/Command\\\/Generate.php(153): OCA\\\\PreviewGenerator\\\\Command\\\\Generate->parseFolder(Object(OC\\\\Files\\\\Node\\\\Folder))\\n#20 \\\/var\\\/www\\\/clients\\\/client3\\\/web12\\\/web\\\/apps\\\/previewgenerator\\\/lib\\\/Command\\\/Generate.php(153): OCA\\\\PreviewGenerator\\\\Command\\\\Generate->parseFolder(Object(OC\\\\Files\\\\Node\\\\Folder))\\n#21 \\\/var\\\/www\\\/clients\\\/client3\\\/web12\\\/web\\\/apps\\\/previewgenerator\\\/lib\\\/Command\\\/Generate.php(153): OCA\\\\PreviewGenerator\\\\Command\\\\Generate->parseFolder(Object(OC\\\\Files\\\\Node\\\\Folder))\\n#22 \\\/var\\\/www\\\/clients\\\/client3\\\/web12\\\/web\\\/apps\\\/previewgenerator\\\/lib\\\/Command\\\/Generate.php(153): OCA\\\\PreviewGenerator\\\\Command\\\\Generate->parseFolder(Object(OC\\\\Files\\\\Node\\\\Folder))\\n#23 \\\/var\\\/www\\\/clients\\\/client3\\\/web12\\\/web\\\/apps\\\/previewgenerator\\\/lib\\\/Command\\\/Generate.php(142): OCA\\\\PreviewGenerator\\\\Command\\\\Generate->parseFolder(Object(OC\\\\Files\\\\Node\\\\Folder))\\n#24 \\\/var\\\/www\\\/clients\\\/client3\\\/web12\\\/web\\\/apps\\\/previewgenerator\\\/lib\\\/Command\\\/Generate.php(96): OCA\\\\PreviewGenerator\\\\Command\\\\Generate->generateUserPreviews(Object(OC\\\\User\\\\User))\\n#25 \\\/var\\\/www\\\/clients\\\/client3\\\/web12\\\/web\\\/lib\\\/private\\\/User\\\/Manager.php(410): OCA\\\\PreviewGenerator\\\\Command\\\\Generate->OCA\\\\PreviewGenerator\\\\Command\\\\{closure}(Object(OC\\\\User\\\\User))\\n#26 \\\/var\\\/www\\\/clients\\\/client3\\\/web12\\\/web\\\/apps\\\/previewgenerator\\\/lib\\\/Command\\\/Generate.php(97): OC\\\\User\\\\Manager->callForSeenUsers(Object(Closure))\\n#27 \\\/var\\\/www\\\/clients\\\/client3\\\/web12\\\/web\\\/3rdparty\\\/symfony\\\/console\\\/Command\\\/Command.php(256): OCA\\\\PreviewGenerator\\\\Command\\\\Generate->execute(Object(Symfony\\\\Component\\\\Console\\\\Input\\\\ArgvInput), Object(Symfony\\\\Component\\\\Console\\\\Output\\\\ConsoleOutput))\\n#28 \\\/var\\\/www\\\/clients\\\/client3\\\/web12\\\/web\\\/3rdparty\\\/symfony\\\/console\\\/Application.php(818): Symfony\\\\Component\\\\Console\\\\Command\\\\Command->run(Object(Symfony\\\\Component\\\\Console\\\\Input\\\\ArgvInput), Object(Symfony\\\\Component\\\\Console\\\\Output\\\\ConsoleOutput))\\n#29 \\\/var\\\/www\\\/clients\\\/client3\\\/web12\\\/web\\\/3rdparty\\\/symfony\\\/console\\\/Application.php(186): Symfony\\\\Component\\\\Console\\\\Application->doRunCommand(Object(OCA\\\\PreviewGenerator\\\\Command\\\\Generate), Object(Symfony\\\\Component\\\\Console\\\\Input\\\\ArgvInput), Object(Symfony\\\\Component\\\\Console\\\\Output\\\\ConsoleOutput))\\n#30 \\\/var\\\/www\\\/clients\\\/client3\\\/web12\\\/web\\\/3rdparty\\\/symfony\\\/console\\\/Application.php(117): Symfony\\\\Component\\\\Console\\\\Application->doRun(Object(Symfony\\\\Component\\\\Console\\\\Input\\\\ArgvInput), Object(Symfony\\\\Component\\\\Console\\\\Output\\\\ConsoleOutput))\\n#31 \\\/var\\\/www\\\/clients\\\/client3\\\/web12\\\/web\\\/lib\\\/private\\\/Console\\\/Application.php(169): Symfony\\\\Component\\\\Console\\\\Application->run(Object(Symfony\\\\Component\\\\Console\\\\Input\\\\ArgvInput), Object(Symfony\\\\Component\\\\Console\\\\Output\\\\ConsoleOutput))\\n#32 \\\/var\\\/www\\\/clients\\\/client3\\\/web12\\\/web\\\/console.php(90): OC\\\\Console\\\\Application->run()\\n#33 \\\/var\\\/www\\\/clients\\\/client3\\\/web12\\\/web\\\/occ(11): require_once('\\\/var\\\/www\\\/client...')\\n#34 {main}\",\"File\":\"\\\/var\\\/www\\\/clients\\\/client3\\\/web12\\\/web\\\/lib\\\/private\\\/Files\\\/Node\\\/Root.php\",\"Line\":366}","level":3,"time":"2017-01-30T02:12:37+00:00","method":"--","url":"--","user":"--","version":"11.0.1.2"}
{"reqId":"H59fJJ+USGx7MaHFmW6g","remoteAddr":"","app":"files","message":"Backends provided no user object for ","level":3,"time":"2017-01-30T02:12:37+00:00","method":"--","url":"--","user":"--","version":"11.0.1.2"}
{"reqId":"H59fJJ+USGx7MaHFmW6g","remoteAddr":"","app":"no app in context","message":"Exception: {\"Exception\":\"OC\\\\User\\\\NoUserException\",\"Message\":\"Backends provided no user object\",\"Code\":0,\"Trace\":\"#0 [internal function]: OC\\\\Files\\\\Node\\\\Root->getUserFolder(NULL)\\n#1 \\\/var\\\/www\\\/clients\\\/client3\\\/web12\\\/web\\\/lib\\\/private\\\/Files\\\/Node\\\/LazyRoot.php(65): call_user_func_array(Array, Array)\\n#2 \\\/var\\\/www\\\/clients\\\/client3\\\/web12\\\/web\\\/lib\\\/private\\\/Files\\\/Node\\\/LazyRoot.php(282): OC\\\\Files\\\\Node\\\\LazyRoot->__call('getUserFolder', Array)\\n#3 \\\/var\\\/www\\\/clients\\\/client3\\\/web12\\\/web\\\/apps\\\/files_downloadactivity\\\/lib\\\/Activity\\\/Listener.php(141): OC\\\\Files\\\\Node\\\\LazyRoot->getUserFolder(NULL)\\n#4 \\\/var\\\/www\\\/clients\\\/client3\\\/web12\\\/web\\\/apps\\\/files_downloadactivity\\\/lib\\\/Activity\\\/Listener.php(77): OCA\\\\FilesDownloadActivity\\\\Activity\\\\Listener->getSourcePathAndOwner('\\\/var\\\/www\\\/client...')\\n#5 \\\/var\\\/www\\\/clients\\\/client3\\\/web12\\\/web\\\/apps\\\/files_downloadactivity\\\/lib\\\/AppInfo\\\/Application.php(47): OCA\\\\FilesDownloadActivity\\\\Activity\\\\Listener->readFile('\\\/var\\\/www\\\/client...')\\n#6 \\\/var\\\/www\\\/clients\\\/client3\\\/web12\\\/web\\\/lib\\\/private\\\/legacy\\\/hook.php(106): OCA\\\\FilesDownloadActivity\\\\AppInfo\\\\Application->listenReadFile(Array)\\n#7 \\\/var\\\/www\\\/clients\\\/client3\\\/web12\\\/web\\\/lib\\\/private\\\/Files\\\/View.php(1243): OC_Hook::emit('OC_Filesystem', 'read', Array)\\n#8 \\\/var\\\/www\\\/clients\\\/client3\\\/web12\\\/web\\\/lib\\\/private\\\/Files\\\/View.php(1113): OC\\\\Files\\\\View->runHooks(Array, '\\\/var\\\/www\\\/client...')\\n#9 \\\/var\\\/www\\\/clients\\\/client3\\\/web12\\\/web\\\/lib\\\/private\\\/Files\\\/View.php(577): OC\\\\Files\\\\View->basicOperation('file_get_conten...', '\\\/var\\\/www\\\/client...', Array)\\n#10 \\\/var\\\/www\\\/clients\\\/client3\\\/web12\\\/web\\\/lib\\\/private\\\/Files\\\/Filesystem.php(719): OC\\\\Files\\\\View->file_get_contents('\\\/var\\\/www\\\/client...')\\n#11 \\\/var\\\/www\\\/clients\\\/client3\\\/web12\\\/web\\\/lib\\\/private\\\/legacy\\\/image.php(597): OC\\\\Files\\\\Filesystem::file_get_contents('\\\/var\\\/www\\\/client...')\\n#12 \\\/var\\\/www\\\/clients\\\/client3\\\/web12\\\/web\\\/lib\\\/private\\\/Preview\\\/MP3.php(80): OC_Image->loadFromFile('\\\/var\\\/www\\\/client...')\\n#13 \\\/var\\\/www\\\/clients\\\/client3\\\/web12\\\/web\\\/lib\\\/private\\\/Preview\\\/MP3.php(64): OC\\\\Preview\\\\MP3->getNoCoverThumbnail()\\n#14 \\\/var\\\/www\\\/clients\\\/client3\\\/web12\\\/web\\\/lib\\\/private\\\/Preview\\\/GeneratorHelper.php(54): OC\\\\Preview\\\\MP3->getThumbnail('\\\/files\\\/Archiv\\\/K...', 2048, 2048, false, Object(OC\\\\Files\\\\View))\\n#15 \\\/var\\\/www\\\/clients\\\/client3\\\/web12\\\/web\\\/lib\\\/private\\\/Preview\\\/Generator.php(155): OC\\\\Preview\\\\GeneratorHelper->getThumbnail(Object(OC\\\\Preview\\\\MP3), Object(OC\\\\Files\\\\Node\\\\File), 2048, 2048)\\n#16 \\\/var\\\/www\\\/clients\\\/client3\\\/web12\\\/web\\\/lib\\\/private\\\/Preview\\\/Generator.php(108): OC\\\\Preview\\\\Generator->getMaxPreview(Object(OC\\\\Files\\\\SimpleFS\\\\SimpleFolder), Object(OC\\\\Files\\\\Node\\\\File), 'audio\\\/mpeg')\\n#17 \\\/var\\\/www\\\/clients\\\/client3\\\/web12\\\/web\\\/lib\\\/private\\\/PreviewManager.php(182): OC\\\\Preview\\\\Generator->getPreview(Object(OC\\\\Files\\\\Node\\\\File), 32, 32, true, 'fill', 'audio\\\/mpeg')\\n#18 \\\/var\\\/www\\\/clients\\\/client3\\\/web12\\\/web\\\/apps\\\/previewgenerator\\\/lib\\\/Command\\\/Generate.php(167): OC\\\\PreviewManager->getPreview(Object(OC\\\\Files\\\\Node\\\\File), 32, 32, true)\\n#19 \\\/var\\\/www\\\/clients\\\/client3\\\/web12\\\/web\\\/apps\\\/previewgenerator\\\/lib\\\/Command\\\/Generate.php(155): OCA\\\\PreviewGenerator\\\\Command\\\\Generate->parseFile(Object(OC\\\\Files\\\\Node\\\\File))\\n#20 \\\/var\\\/www\\\/clients\\\/client3\\\/web12\\\/web\\\/apps\\\/previewgenerator\\\/lib\\\/Command\\\/Generate.php(153): OCA\\\\PreviewGenerator\\\\Command\\\\Generate->parseFolder(Object(OC\\\\Files\\\\Node\\\\Folder))\\n#21 \\\/var\\\/www\\\/clients\\\/client3\\\/web12\\\/web\\\/apps\\\/previewgenerator\\\/lib\\\/Command\\\/Generate.php(153): OCA\\\\PreviewGenerator\\\\Command\\\\Generate->parseFolder(Object(OC\\\\Files\\\\Node\\\\Folder))\\n#22 \\\/var\\\/www\\\/clients\\\/client3\\\/web12\\\/web\\\/apps\\\/previewgenerator\\\/lib\\\/Command\\\/Generate.php(153): OCA\\\\PreviewGenerator\\\\Command\\\\Generate->parseFolder(Object(OC\\\\Files\\\\Node\\\\Folder))\\n#23 \\\/var\\\/www\\\/clients\\\/client3\\\/web12\\\/web\\\/apps\\\/previewgenerator\\\/lib\\\/Command\\\/Generate.php(153): OCA\\\\PreviewGenerator\\\\Command\\\\Generate->parseFolder(Object(OC\\\\Files\\\\Node\\\\Folder))\\n#24 \\\/var\\\/www\\\/clients\\\/client3\\\/web12\\\/web\\\/apps\\\/previewgenerator\\\/lib\\\/Command\\\/Generate.php(153): OCA\\\\PreviewGenerator\\\\Command\\\\Generate->parseFolder(Object(OC\\\\Files\\\\Node\\\\Folder))\\n#25 \\\/var\\\/www\\\/clients\\\/client3\\\/web12\\\/web\\\/apps\\\/previewgenerator\\\/lib\\\/Command\\\/Generate.php(142): OCA\\\\PreviewGenerator\\\\Command\\\\Generate->parseFolder(Object(OC\\\\Files\\\\Node\\\\Folder))\\n#26 \\\/var\\\/www\\\/clients\\\/client3\\\/web12\\\/web\\\/apps\\\/previewgenerator\\\/lib\\\/Command\\\/Generate.php(96): OCA\\\\PreviewGenerator\\\\Command\\\\Generate->generateUserPreviews(Object(OC\\\\User\\\\User))\\n#27 \\\/var\\\/www\\\/clients\\\/client3\\\/web12\\\/web\\\/lib\\\/private\\\/User\\\/Manager.php(410): OCA\\\\PreviewGenerator\\\\Command\\\\Generate->OCA\\\\PreviewGenerator\\\\Command\\\\{closure}(Object(OC\\\\User\\\\User))\\n#28 \\\/var\\\/www\\\/clients\\\/client3\\\/web12\\\/web\\\/apps\\\/previewgenerator\\\/lib\\\/Command\\\/Generate.php(97): OC\\\\User\\\\Manager->callForSeenUsers(Object(Closure))\\n#29 \\\/var\\\/www\\\/clients\\\/client3\\\/web12\\\/web\\\/3rdparty\\\/symfony\\\/console\\\/Command\\\/Command.php(256): OCA\\\\PreviewGenerator\\\\Command\\\\Generate->execute(Object(Symfony\\\\Component\\\\Console\\\\Input\\\\ArgvInput), Object(Symfony\\\\Component\\\\Console\\\\Output\\\\ConsoleOutput))\\n#30 \\\/var\\\/www\\\/clients\\\/client3\\\/web12\\\/web\\\/3rdparty\\\/symfony\\\/console\\\/Application.php(818): Symfony\\\\Component\\\\Console\\\\Command\\\\Command->run(Object(Symfony\\\\Component\\\\Console\\\\Input\\\\ArgvInput), Object(Symfony\\\\Component\\\\Console\\\\Output\\\\ConsoleOutput))\\n#31 \\\/var\\\/www\\\/clients\\\/client3\\\/web12\\\/web\\\/3rdparty\\\/symfony\\\/console\\\/Application.php(186): Symfony\\\\Component\\\\Console\\\\Application->doRunCommand(Object(OCA\\\\PreviewGenerator\\\\Command\\\\Generate), Object(Symfony\\\\Component\\\\Console\\\\Input\\\\ArgvInput), Object(Symfony\\\\Component\\\\Console\\\\Output\\\\ConsoleOutput))\\n#32 \\\/var\\\/www\\\/clients\\\/client3\\\/web12\\\/web\\\/3rdparty\\\/symfony\\\/console\\\/Application.php(117): Symfony\\\\Component\\\\Console\\\\Application->doRun(Object(Symfony\\\\Component\\\\Console\\\\Input\\\\ArgvInput), Object(Symfony\\\\Component\\\\Console\\\\Output\\\\ConsoleOutput))\\n#33 \\\/var\\\/www\\\/clients\\\/client3\\\/web12\\\/web\\\/lib\\\/private\\\/Console\\\/Application.php(169): Symfony\\\\Component\\\\Console\\\\Application->run(Object(Symfony\\\\Component\\\\Console\\\\Input\\\\ArgvInput), Object(Symfony\\\\Component\\\\Console\\\\Output\\\\ConsoleOutput))\\n#34 \\\/var\\\/www\\\/clients\\\/client3\\\/web12\\\/web\\\/console.php(90): OC\\\\Console\\\\Application->run()\\n#35 \\\/var\\\/www\\\/clients\\\/client3\\\/web12\\\/web\\\/occ(11): require_once('\\\/var\\\/www\\\/client...')\\n#36 {main}\",\"File\":\"\\\/var\\\/www\\\/clients\\\/client3\\\/web12\\\/web\\\/lib\\\/private\\\/Files\\\/Node\\\/Root.php\",\"Line\":366}","level":3,"time":"2017-01-30T02:12:37+00:00","method":"--","url":"--","user":"--","version":"11.0.1.2"}
As you can see, the filename is truncated:
MP3->getThumbnail(ā\/files\/Archiv\/Kā¦ā, 2048, 2048, false, O
So, how can i gather useful debug information?