如何解释sybase限制算子(VA = 1)(4)(0)(0)(0)(0)

Question

有人能帮助澄清限制操作员吗？

据我所知，Sybase限制运算符用于计算基于列的表达式。但是，在查询计划中，我仍然不知道限制操作符的确切含义。

下面是我的sql的查询计划片段。限制算子(VA =1) (4)(0)(0)(0)(0) (0)(0)(0)(0)(0)(0)(0)(0)(0)是什么意思？

    10 operator(s) under root



   |ROOT:EMIT Operator (VA = 10)

   |

   |   |SCALAR AGGREGATE Operator (VA = 9)

   |   |  Evaluate Ungrouped COUNT AGGREGATE.

   |   |

   |   |   |N-ARY NESTED LOOP JOIN Operator (VA = 8) has 7 children.

   |   |   |

   |   |   |   |RESTRICT Operator (VA = 1)(4)(0)(0)(0)(0)

   |   |   |   |

   |   |   |   |   |SCAN Operator (VA = 0)

   |   |   |   |   |  FROM TABLE

   |   |   |   |   |  trade

   |   |   |   |   |  t

   |   |   |   |   |  Index : i1

   |   |   |   |   |  Forward Scan.

   |   |   |   |   |  Positioning by key.

   |   |   |   |   |  Keys are:

   |   |   |   |   |    order_number ASC

   |   |   |   |   |  Using I/O Size 16 Kbytes for index leaf pages.

   |   |   |   |   |  With LRU Buffer Replacement Strategy for index leaf pages.

   |   |   |   |   |  Using I/O Size 16 Kbytes for data pages.

   |   |   |   |   |  With LRU Buffer Replacement Strategy for data pages.

   |   |   |

   |   |   |   |SCAN Operator (VA = 2)

   |   |   |   |  FROM TABLE

   |   |   |   |  product

   |   |   |   |  mp

   |   |   |   |  Index : mp

   |   |   |   |  Forward Scan.

   |   |   |   |  Positioning by key.

   |   |   |   |  Keys are:

   |   |   |   |    prod_id ASC

   |   |   |   |  Using I/O Size 16 Kbytes for index leaf pages.

   |   |   |   |  With LRU Buffer Replacement Strategy for index leaf pages.

   |   |   |   |  Using I/O Size 16 Kbytes for data pages.

   |   |   |   |  With LRU Buffer Replacement Strategy for data pages.

   |   |   |

   |   |   |   |SCAN Operator (VA = 3)

   |   |   |   |  FROM TABLE

   |   |   |   |  Accounts

   |   |   |   |  a

   |   |   |   |  Index : i2

   |   |   |   |  Forward Scan.

   |   |   |   |  Positioning by key.

   |   |   |   |  Index contains all needed columns. Base table will not be read.

   |   |   |   |  Keys are:

   |   |   |   |    account ASC

   |   |   |   |  Using I/O Size 16 Kbytes for index leaf pages.

   |   |   |   |  With LRU Buffer Replacement Strategy for index leaf pages.

Answer 1

显示计划输出的一部分，如操作符后面的数字，是ASE优化器的内部部件。没有关于这些问题的有记录的信息，而这些信息包括在帮助技术支持解决问题方面。'VA = n‘部分只是反映了查询计划中每个操作符的唯一数字'n’。