SQL Server-用最小和最大范围索引映射表

Question

I am having an issue with performance when it comes to using a mapping table that has multiple ranges. The mapping table is laid out like the following.

ResultNumber param1Min param1Max param2Min param2Max ... param8min param8max

Those are the column names of the mapping table. What is joined on the table is param1, param2, param3 ... param8 .

I need to find the row where (param1 is between param1Min and param1Max) and (param2 is between param2Min and param2Max) ... and get the Result number from the matching row. The issue is the mapping table has over 2 million rows and I am having trouble indexing this table because it has to use ranges to find what it needs.

Any thoughts on how to speed this up?

I also included the index I tried that did not help at all

SELECT ResultNumber
FROM   MappingTable
WHERE  ( param1 BETWEEN param1Min AND param1Max )
       AND ( param2 BETWEEN param2Min AND param2Max )
       AND ( param3 BETWEEN param3Min AND param3Max ) 
 ...



CREATE CLUSTERED INDEX [index] ON [dbo].MappingTable 
(
    [param1Min] ASC,
    [param1Max] ASC,
    [param2Min] ASC,
    [param2Max] ASC,
    [param3Min] ASC,
    [param3Max] ASC,
)WITH (PAD_INDEX  = OFF, STATISTICS_NORECOMPUTE  = OFF, SORT_IN_TEMPDB = OFF, IGNORE_DUP_KEY = OFF, DROP_EXISTING = OFF, ONLINE = OFF, ALLOW_ROW_LOCKS  = ON, ALLOW_PAGE_LOCKS  = ON)

Answer 1

Are the "param1, param2, param3 ... param8" variables or columns in another table? In any event I would break it into chunks to get usage out of the indexes and slice down the work that needs to be done with each subsequent parameter check.

You want to create a clustered index on resultnumber and only resultnumber and then create nonclustered indexes on resultnumber, param#min, param#max combinations. Should be a total of 9 indexes on [dbo].[MappingTable].

Create Clustered Index ix_rn On [dbo].[MappingTable] (resultnumber)
Create NonClustered Index ix_p1 On [dbo].[MappingTable] (resultnumber, param1min, param1max)
...
Create NonClustered Index ix_p8 On [dbo].[MappingTable] (resultnumber, param8min, param8max)

This will allow you to get performance gains from the code below. It should run extremely fast.

With    param1 As
(
        Select  resultnumber
        From    [dbo].[MappingTable]
        Where   @param1 Between param1min And param1max
),      param2 As
(
        Select  m.resultNumber
        From    [dbo].[MappingTable] m
        Join    param1 p1
                On  m.resultnumber = p1.resultnumber
        Where   @param2 Between param2min And param2max
),      param3 As
(
        ...
        ...
),      param8 As
(
        Select  m.resultNumber
        From    [dbo].[MappingTable] m
        Join    param7 p7
                On  m.resultnumber = p7.resultnumber
        Where   @param8 Between param8min And param8max
)
Select  resultNumber
From    param8

A table implementation would look something like this. It would still take awhile depending on the size of the table you're joining, but it should still run faster than your original query.

With    param1 As
(
        Select  m.resultnumber, w.tableIdentityValue
        From    [dbo].[MappingTable] m
        Join    whateverJoinTable w
                On w.param1 Between m.param1min And m.param1max
),      param2 As
(
        Select  m.resultNumber, w.tableIdentityValue
        From    [dbo].[MappingTable] m
        Join    param1 p1
                On  m.resultnumber = p1.resultnumber
        Join    whateverJoinTable w
                On  m.tableIdentityValue = w.tableIdentityValue
                And w.param2 Between m.param2min And m.param2max
),      param3 As
(
        ...
        ...
),      param8 As
(
        Select  m.resultNumber, w.tableIdentityValue
        From    [dbo].[MappingTable] m
        Join    param7 p7
                On  m.resultnumber = p7.resultnumber
        Join    whateverJoinTable w
                On  m.tableIdentityValue = w.tableIdentityValue
                And w.param8 Between m.param8min And m.param8max
)
Select  resultNumber, tableIdentityValue
From    param8