在这种情况下，

• HOLDLOCK = SERIALIZABLE = 持续时间，并发
• TABLOCKX = 独占表锁

这两个概念是不同的，你想要的也不是.

The 2 concepts are different and neither does what you want.

做你想做的事，避免竞争条件，需要强制一个非阻塞(READPAST)排他(UPDLOCK)行级(ROWLOCK)锁，.您还可以使用 OUTPUT 子句使其成为具有原子性的单个语句.这可以很好地扩展.

To do what you want, to avoid race conditions, you need to force a non-blocking (READPAST) exclusive (UPDLOCK) row level (ROWLOCK) lock,. You can also use the OUTPUT clause to make it a single statement that will be atomic. This scales well.

UPDATE
    E
SET
   [status] = 'PROCESSING', [username] = @Username
OUTPUT
   INSERTED.*
FROM
   (
    SELECT TOP 1 id, [status], [username]
    FROM Exceptions (ROWLOCK, READPAST, UPDLOCK)
    WHERE [status] = 'READY'
    ORDER BY id
   ) E

总的来说，锁有3个方面

In general, locks have 3 aspects

• 粒度 = 锁定的内容 = 行、页、表(PAGLOCK、ROWLOCK、TABLOCK)
• 隔离级别 = 锁定持续时间、并发性(HOLDLOCK、READCOMMITTED、REPEATABLEREAD、SERIALIZABLE)
• 模式 = 共享/排他性 (UPDLOCK, XLOCK)

和

• 组合"例如 NOLOCK, TABLOCKX