优化SQL与Interbase的

Question

我是从我以前的问题灵感来自很好的答案有关SQL。 现在这个SQL是一个DB与2009年Interbase的是约21 GB的大小运行。

SELECT DistanceAsMeters, AddrDistance.Bold_Id, AddrDistance.Created, AddressFrom.CityName_CO as FromCity, AddressTo.CityName_CO as ToCity
FROM AddrDistance
LEFT JOIN Address AddressFrom ON AddrDistance.FromAddress = AddressFrom.Bold_Id
LEFT JOIN Address AddressTo ON AddrDistance.ToAddress = AddressTo.Bold_Id
Where  DistanceAsMeters = 0 and PseudoDistanceAsCostKm = 0
       and not AddrDistance.bold_id in (select bold_id from DistanceQueryTask)
Order By Created Desc

有84万行与AddrDistance 190000行与地址和4 DistanceQueryTask。

的问题是，可以这样做快？我想，同样的查询运行多次选择bold_id从DistanceQueryTask 。请注意，我不感兴趣，在存储过程中，只是简单的SQL：）

<强> EDIT1 以下是当前执行计划：

Statement: SELECT DistanceAsMeters, AddrDistance.Bold_Id, AddrDistance.Created, AddressFrom.CityName_CO as FromCity, AddressTo.CityName_CO as ToCity
FROM AddrDistance
LEFT JOIN Address AddressFrom ON AddrDistance.FromAddress = AddressFrom.Bold_Id
LEFT JOIN Address AddressTo ON AddrDistance.ToAddress = AddressTo.Bold_Id
Where  DistanceAsMeters = 0 and PseudoDistanceAsCostKm = 0
       and not AddrDistance.bold_id in (select bold_id from DistanceQueryTask)
Order By Created Desc

PLAN (DISTANCEQUERYTASK INDEX (RDB$PRIMARY218))
PLAN SORT (JOIN (JOIN (ADDRDISTANCE NATURAL,ADDRESSFROM INDEX (RDB$PRIMARY234)),ADDRESSTO INDEX (RDB$PRIMARY234)))

和是的，DistanceQueryTask是指具有低的号码，如果在数据库中的行。

Answer 1

使用左联接和子查询将任何查询减慢。

您可以得到一些改进，以正确的索引（上Bold_id，DistanceMeters，PseudoDistanceAsCostKm）请记住，更多的索引增加数据库的大小

Answer 2

我想bold_id是你的钥匙，因而适当的索引。点击 然后更换子查询和不...在由加入可能有助于优化。

SELECT DistanceAsMeters, Bold_Id, Created, AddressFrom.CityName_CO as FromCity, AddressTo.CityName_CO as ToCity
FROM AddrDistance
LEFT JOIN Address AddressFrom ON AddrDistance.FromAddress = AddressFrom.Bold_Id
LEFT JOIN Address AddressTo ON AddrDistance.ToAddress = AddressTo.Bold_Id
LEFT JOIN DistanceQueryTask ON AddrDistance.bold_id = DistanceQueryTask.bold_id
Where  DistanceAsMeters = 0 and PseudoDistanceAsCostKm = 0
  and DistanceQueryTask.bold_id is null
Order By Created Desc

Answer 3

创建此部分的索引：（DistanceAsMeters = 0和PseudoDistanceAsCostKm = 0） 因为它确实（差）表扫描它：ADDRDISTANCE自然科学

和尝试使用由弗朗索瓦规定的加入，而不是子查询中。

Answer 4

作为丹尼尔和Andre sugges索引有很大帮助。结果 我建议这个指数（DistanceMeters，PseudoDistanceAsCostKm，Bold_id），由于第一部件2的索引是恒定的，则其被读取所需的索引的SmaI位部分。

如果这是一个事实，FROMADDRESS和/或存在的toAddress你可以改变LEFT JOIN到INNER JOIN，因为它往往是更快（查询优化器可以作出一些假设）。