Question

我正在处理性能不佳的查询，该查询无法处理具有数百万条记录的大型数据集。参数作为JSON传递到存储过程中，并在该过程中提取。

在公用表表达式中使用OPENJSON分配JSON数据时，查询需要 74秒：

create procedure [getResults] ( @Input nvarchar(max) = '' ) as
declare @MaxResults int = json_value(@Input, '$.MaxResults');

with SearchInfo (FirstName, MiddleName, LastName) as (
    select FirstName, MiddleName, LastName
    from openjson(@Input)
    with ( FirstName nvarchar(50) '$.FirstName', MiddleName nvarchar(50) '$.MiddleName', LastName nvarchar(50) '$.LastName' )
)
select top (@RowCount) * from SearchInfo cross apply getMatches(FirstName, MiddleName, LastName)

如果将OPENJSON移到公用表表达式之外，则查询仅需 18秒：

create procedure [getResults] ( @Input nvarchar(max) = '' ) as
declare @MaxResults int = json_value(@Input, '$.MaxResults');
declare @FirstName nvarchar(50), @MiddleName nvarchar(50), @LastName nvarchar(50);

select @FirstName = FirstName, @MiddleName = MiddleName, @LastName = LastName
from openjson(@Input)
with ( FirstName = '$.FirstName', MiddleName = '$.MiddleName', LastName = '$.LastName' );

with SearchInfo (FirstName, MiddleName, LastName) as (
    select FirstName, MiddleName, LastName
    from (values (@FirstName, @MiddleName, @LastName))
)
select top (@RowCount) * from SearchInfo cross apply getMatches(@FirstName, @MiddleName, @LastName)

如果我完全放弃OPENJSON，并且仅使用JSON_VALUE，则查询仅需 4秒：

create procedure [getResults] ( @Input nvarchar(max) = '' ) as
declare @MaxResults int = json_value(@Input, '$.MaxResults');
declare @FirstName nvarchar(50) = json_value(@Input, '$.FirstName');
declare @MiddleName nvarchar(1) = json_value(@Input, '$.MiddleName');
declare @LastName nvarchar(50) = json_value(@Input, '$.LastName');

with SearchInfo (FirstName, MiddleName, LastName) as (
    select FirstName, MiddleName, LastName
    from (values (@FirstName, @MiddleName , @LastName))
)
select top (@RowCount) * from SearchInfo cross apply getMatches(@FirstName, @MiddleName, @LastName)

最后，如果我完全删除JSON调用，则查询仅需 1秒：

create procedure [getResults] ( @Input nvarchar(max) = '' ) as
declare @MaxResults int = json_value(@Input, '$.MaxResults');
declare @FirstName nvarchar(50) = 'Chris';
declare @MiddleName nvarchar(1) = 'H';
declare @LastName nvarchar(50) = 'Schiffhauer';

select @FirstName = FirstName, @MiddleName = MiddleName, @LastName = LastName
from openjson(@Input)
with ( FirstName = '$.FirstName', MiddleName = '$.MiddleName', LastName = '$.LastName' );

with SearchInfo (FirstName, MiddleName, LastName) as (
    select FirstName, MiddleName, LastName
    from (values (@FirstName, @MiddleName, @LastName))
)
select top (@RowCount) * from SearchInfo cross apply getMatches(@FirstName, @MiddleName, @LastName)

在SQL Server存储过程中提取JSON数据以免引入不必要的延迟的最快方法是什么？

SQL Server OPENJSON执行不佳

0 个答案: