For a given SQL statement, there are often multipleaccess path choices, and the different access paths usually have different performance characteristics.
对于一个给定的sql语句，往往有多个访问路径选择，而不同的访问路径具有不同的性能特点。
2
A critical section is a portion of code that is protected against multipleaccess.
一个临界段是一段不允许多路访问的受保护的代码。
3
Most providers implement multipleaccess methods, but Web service APIs are common.