sqlite3.dylib:非法多线程访问数据库连接

Question

我有一个使用的iOS应用程序,sqlite3我正面临多线程问题,使应用程序崩溃illegal multi-threaded access to database connection.当然,这是因为我正在使用多线程; 问题是,我的sqlyte3实例配置为使用多线程:

sqlite3_config(SQLITE_CONFIG_MULTITHREAD);

即使我使用多线程(sqlite3构建也使用多线程标志编译),当多个线程同时写入或读取数据库时,它会导致我的应用程序崩溃.

崩溃报告

Application Specific Information:
BUG IN CLIENT OF sqlite3.dylib: illegal multi-threaded access to database connection

Exception Type:  EXC_BREAKPOINT (SIGTRAP)
Exception Codes: 0x0000000000000001, 0x00000001823ed2fc
Termination Signal: Trace/BPT trap: 5
Termination Reason: Namespace SIGNAL, Code 0x5
Terminating Process: exc handler [0]
Triggered by Thread:  12

Thread 12 Crashed:

0   libsqlite3.dylib                0x00000001823ed2fc sqlite3MutexMisuseAssert + 144 (sqlite3.c:23788)
1   libsqlite3.dylib                0x00000001823ed2ec sqlite3MutexMisuseAssert + 128 (once.h:84)
2   libsqlite3.dylib                0x000000018235248c sqlite3LockAndPrepare + 320 (sqlite3.c:23801)
3   MyCodeCall.m ...........

我已经在这个问题上苦苦挣扎了一段时间,我在谷歌上找不到任何关于这个问题的不幸.

UPDATE

+(sqlite3*) getInstance {
  if (instance == NULL) {
    sqlite3_shutdown();
    sqlite3_config(SQLITE_CONFIG_MULTITHREAD);
    sqlite3_initialize();

    NSLog(@"isThreadSafe %d", sqlite3_threadsafe());

    const char *path = [@"./path/to/db/db.sqlite" cStringUsingEncoding:NSUTF8StringEncoding];

    if (sqlite3_open_v2(path, &database, SQLITE_OPEN_READWRITE|SQLITE_OPEN_CREATE, NULL) != SQLITE_OK) {
      NSLog(@"Database opening failed!");
    }
  }

  return instance;
}

Answer 1

事实证明,SQLITE_CONFIG_MULTITHREAD只要您不同时使用相同的连接,模式在多线程环境中运行良好; 这恰好是我的确切场景.因此,要解决此问题,您可以为每个线程打开一个新连接,也可以SQLITE_CONFIG_SERIALIZED使用SQLITE_OPEN_FULLMUTEX标志在完全互斥模式下打开连接.

辅助方法最终如下:

+(sqlite3*) getInstance {
  if (instance == NULL) {
    sqlite3_shutdown();
    sqlite3_config(SQLITE_CONFIG_SERIALIZED);
    sqlite3_initialize();

    NSLog(@"isThreadSafe %d", sqlite3_threadsafe());

    const char *path = [@"./path/to/db/db.sqlite" cStringUsingEncoding:NSUTF8StringEncoding];

    if (sqlite3_open_v2(path, &database, SQLITE_OPEN_READWRITE|SQLITE_OPEN_FULLMUTEX, NULL) != SQLITE_OK) {
      NSLog(@"Database opening failed!");
    }
  }

  return instance;
}

Answer 2

如果有人在 Swift 中遇到这个问题。解决方案将是：

let dbName = "first.db"
static let shared = DatabaseManger()
var db: OpaquePointer?


private init(){
    print("singletone initialized")
    sqlite3_shutdown();
    let dbPath = try! FileManager.default.url(for: .documentDirectory, in: .userDomainMask, appropriateFor: nil, create: false)
        .appendingPathComponent(dbName)
    if sqlite3_open_v2(dbPath.path, &db, SQLITE_OPEN_CREATE | SQLITE_OPEN_READWRITE | SQLITE_OPEN_FULLMUTEX, nil) == SQLITE_OK {
        print("Successfully opened database connection at \(dbPath.path)")
    }
    else {
        print("unable to open database connection")
    }
}

此代码在 swift 版本 4.0 和 4.2 中测试

Answer 3

请使用 SQLite 共享缓存模式 https://www.sqlite.org/sharedcache.html

sqlite3_open_v2(path.path, &db, SQLITE_OPEN_CREATE | SQLITE_OPEN_READWRITE | SQLITE_OPEN_SHAREDCACHE, nil) != SQLITE_OK

SQLITE_OPEN_SHAREDCACHE

100%可靠:)