When you drop or rebuild large indexes, or drop or truncate large tables, the Database Engine defers the actual page deallocations, and their associated locks, until after the transaction commits.

• 在删除或重新生成大型索引时,或者在删除或截断大型表时,数据库引擎将延迟实际页释放及其关联锁,直至事务提交完毕为止。