c# - SQLiteConnection.BeginTransaction 是否在数据库锁定时重试？

Question

我在多线程 Windows 桌面程序中使用 SQLite (System.Data.SQLite.dll)。我使用这段代码:

using (var cn = new SQLiteConnection(connectionString))
{
    cn.Open();
    using (var tx = cn.BeginTransaction())
    {
          // do some work here

         tx.Commit();
    }
}

我强调程序使用 8 个并发线程同时写入数据库。有时我会在 Visual Studio 输出窗口中看到这条消息:

SQLite error (517): statement aborts at 1: [BEGIN IMMEDIATE] database is locked 

但是根本没有抛出异常，一切都按预期进行。所以我猜 SQLConnection.BeginTrasaction() 在收到 SQLite 错误 (517) 数据库被锁定时会重试。

我说得对吗？

如果是，SQLConnection.BeginTransaction 在抛出异常之前重试了多少次。这是可配置的吗？

Answer 1

这由 BUSY TIMEOUT 处理:

PRAGMA busy_timeout;
PRAGMA busy_timeout = milliseconds;

Query or change the setting of the busy timeout. This pragma is analternative to the sqlite3_busy_timeout() C-language interface whichis made available as a pragma for use with language bindings that donot provide direct access to sqlite3_busy_timeout().

Each database connection can only have a single busy handler. ThisPRAGMA sets the busy handler for the process, possibly overwriting anypreviously set busy handler.

超时间隔在 SQLite.dll 中默认定义为 30 秒。原来你不能改变它，只能通过调用不安全的 C 函数。

来自SQLite C Interface :

int sqlite3_busy_timeout(sqlite3*, int ms);

Calling this routine with an argument less than or equal to zero turns off all busy handlers.