SIGABRT - please_report_this_issue_in_github_realm_realm_core_v_20_1_2

#### SDK and version SDK : `Realm .Net` Version: `20.1.0` #### Observations * How frequent do the crash occur? * Sometimes/Some users * Does it happen in production or during dev/test? * Production * Can the crash be reproduced by you? * No * Can you provide instructions for how we can reproduce it? * Not really #### Crash log / stacktrace ``` Thread 40 Crashed: 0 libsystem_kernel.dylib 0x1e88adf74 __pthread_kill + 8 1 libsystem_pthread.dylib 0x1fa780fa4 pthread_kill + 208 2 libsystem_c.dylib 0x1ac704708 abort + 104 3 realm-wrappers 0x10e44b968 please_report_this_issue_in_github_realm_realm_core_v_20_1_2 + 12 4 realm-wrappers 0x10e44bc74 realm::util::terminate_internal(std::__1::basic_stringstream<char, std::__1::char_traits<char>, std::__1::allocator<char>>&) + 260 5 realm-wrappers 0x10e44bb08 realm::util::terminate_with_info(char const*, char const*, long, char const*, std::initializer_list<realm::util::Printable>&&) + 396 6 realm-wrappers 0x10e44b97c realm::util::terminate(char const*, char const*, long, std::initializer_list<realm::util::Printable>&&) + 20 7 realm-wrappers 0x10e441084 realm::util::EncryptedFileMapping::~EncryptedFileMapping() + 360 8 realm-wrappers 0x10e446128 realm::util::File::MapBase::unmap() + 56 9 realm-wrappers 0x10e36107c std::__1::vector<std::__1::unique_ptr<realm::WriteWindowMgr::MapWindow, std::__1::default_delete<realm::WriteWindowMgr::MapWindow>>, std::__1::allocator<std::__1::unique_ptr<realm::WriteWindowMgr::MapWindow, std::__1::default_delete<realm::WriteWindowMgr::MapWindow>>>>::__destroy_vector::operator()[abi:ne180100]() + 84 10 realm-wrappers 0x10e35bf34 realm::GroupWriter::~GroupWriter() + 120 11 realm-wrappers 0x10e33eebc realm::DB::low_level_commit(unsigned long long, realm::Transaction&, bool) + 1400 12 realm-wrappers 0x10e33e84c realm::DB::do_commit(realm::Transaction&, bool) + 140 13 realm-wrappers 0x10e439a28 realm::Transaction::commit_and_continue_as_read(bool) + 72 14 realm-wrappers 0x10e20eecc realm::_impl::RealmCoordinator::commit_write(realm::Realm&, bool) + 100 15 realm-wrappers 0x10e25e64c realm::Realm::commit_transaction() + 140 16 realm-wrappers 0x10e1dd96c shared_realm_commit_transaction + 40 17 SnagR.Forms.iOS 0x106e16e70 0x100b68000 + 103476848 18 SnagR.Forms.iOS 0x106ddbc7c 0x100b68000 + 103234684 19 SnagR.Forms.iOS 0x106eb9b94 0x100b68000 + 104143764 20 SnagR.Forms.iOS 0x101ca0458 0x100b68000 + 18056280 21 SnagR.Forms.iOS 0x101cb7370 0x100b68000 + 18150256 22 SnagR.Forms.iOS 0x101ca0458 0x100b68000 + 18056280 23 Mono 0x10f15bc4c mono_jit_runtime_invoke + 1136 24 Mono 0x10f21641c mono_runtime_invoke_checked + 148 25 Mono 0x10f21bdb8 mono_runtime_delegate_try_invoke + 168 26 Mono 0x10f26406c start_wrapper_internal + 604 27 Mono 0x10f263df8 start_wrapper + 68 28 libsystem_pthread.dylib 0x1fa77f82c _pthread_start + 104 29 libsystem_pthread.dylib 0x1fa77bcd8 thread_start + 8 ``` #### Steps & Code to Reproduce We are using Realm as our main app's DB. The realm DB is configured with an encryption key. We are seeing this exception on iOS devices (but may or may not exist on other platforms as well). Users are experiencing app crashes from time to time. The crash seems to occur for: * Rather large DB files ~200MB * On devices with limited amount of RAM (2 - 4 GB) * When the app is using a transaction to insert/delete couple thousands of records As the crash is caused by a low level exception in Realm, the app does not catch it, and crashes. Unfortunately we are not able to reproduce the problem on our end, but it seems to affect our users quite often 😕. Most of the time, relaunching the app and retrying allows the user to go past this problem (temporarily). Could it be caused by a memory problem? Anything I can do to help diagnose this problem, even though we hardly can reproduce the problem on our testing devices? Thank you.