使用TSQL解析JSON，提高性能

我尝试使用 SQL Server 2016 使用 TSQL 解析 JSON 请求。所以我使用这个函数：

ALTER FUNCTION [dbo].[AA_F_ParseJSON]( @JSON NVARCHAR(MAX))

    RETURNS @hierarchy TABLE
      (
       Element_ID INT IDENTITY(1, 1) NOT NULL, /* internal surrogate primary key gives the order of parsing and the list order */
       SequenceNo [int] NULL, /* the place in the sequence for the element */
       Parent_ID INT null, /* if the element has a parent then it is in this column. The document is the ultimate parent, so you can get the structure from recursing from the document */
       Object_ID INT null, /* each list or object has an object id. This ties all elements to a parent. Lists are treated as objects here */
       Name NVARCHAR(2000) NULL, /* the Name of the object */
       StringValue NVARCHAR(MAX) NOT NULL,/*the string representation of the value of the element. */
       ValueType VARCHAR(10) NOT null /* the declared type of the value represented as a string in StringValue*/
      )
    AS
    BEGIN
      DECLARE
        @FirstObject INT, --the index of the first open bracket found in the JSON string
        @OpenDelimiter INT,--the index of the next open bracket found in the JSON string
        @NextOpenDelimiter INT,--the index of subsequent open bracket found in the JSON string
        @NextCloseDelimiter INT,--the index of subsequent close bracket found in the JSON string
        @Type NVARCHAR(10),--whether it denotes an object or an array
        @NextCloseDelimiterChar CHAR(1),--either a '}' or a ']'
        @Contents NVARCHAR(MAX), --the unparsed contents of the bracketed expression
        @Start INT, --index of the start of the token that you are parsing
        @end INT,--index of the end of the token that you are parsing
        @param INT,--the parameter at the end of the next Object/Array token
        @EndOfName INT,--the index of the start of the parameter at end of Object/Array token
        @token NVARCHAR(200),--either a string or object
        @value NVARCHAR(MAX), -- the value as a string
        @SequenceNo int, -- the sequence number within a list
        @Name NVARCHAR(200), --the Name as a string
        @Parent_ID INT,--the next parent ID to allocate
        @lenJSON INT,--the current length of the JSON String
        @characters NCHAR(36),--used to convert hex to decimal
        @result BIGINT,--the value of the hex symbol being parsed
        @index SMALLINT,--used for parsing the hex value
        @Escape INT --the index of the next escape character
        
      DECLARE @Strings TABLE /* in this temporary table we keep all strings, even the Names of the elements, since they are 'escaped' in a different way, and may contain, unescaped, brackets denoting objects or lists. These are replaced in the JSON string by tokens representing the string */
        (
         String_ID INT IDENTITY(1, 1),
         StringValue NVARCHAR(MAX)
        )
      SELECT--initialise the characters to convert hex to ascii
        @characters='0123456789abcdefghijklmnopqrstuvwxyz',
        @SequenceNo=0, --set the sequence no. to something sensible.
      /* firstly we process all strings. This is done because [{} and ] aren't escaped in strings, which complicates an iterative parse. */
        @Parent_ID=0;
      WHILE 1=1 --forever until there is nothing more to do
        BEGIN
          SELECT
            @start=PATINDEX('%[^a-zA-Z]["]%', @json collate SQL_Latin1_General_CP850_Bin);--next delimited string
          IF @start=0 BREAK --no more so drop through the WHILE loop
          IF SUBSTRING(@json, @start+1, 1)='"' 
            BEGIN --Delimited Name
              SET @start=@Start+1;
              SET @end=PATINDEX('%[^\]["]%', RIGHT(@json, LEN(@json+'|')-@start) collate SQL_Latin1_General_CP850_Bin);
            END
          IF @end=0 --either the end or no end delimiter to last string
            BEGIN-- check if ending with a double slash...
             SET @end=PATINDEX('%[\][\]["]%', RIGHT(@json, LEN(@json+'|')-@start) collate SQL_Latin1_General_CP850_Bin);
             IF @end=0 --we really have reached the end 
                BEGIN
                BREAK --assume all tokens found
                END
            END 
          SELECT @token=SUBSTRING(@json, @start+1, @end-1)
          --now put in the escaped control characters
          SELECT @token=REPLACE(@token, FromString, ToString)
          FROM
            (SELECT           '\b', CHAR(08)
             UNION ALL SELECT '\f', CHAR(12)
             UNION ALL SELECT '\n', CHAR(10)
             UNION ALL SELECT '\r', CHAR(13)
             UNION ALL SELECT '\t', CHAR(09)
             UNION ALL SELECT '\"', '"'
             UNION ALL SELECT '\/', '/'
            ) substitutions(FromString, ToString)
        SELECT @token=Replace(@token, '\\', '\')
          SELECT @result=0, @escape=1
      --Begin to take out any hex escape codes
          WHILE @escape>0
            BEGIN
              SELECT @index=0,
              --find the next hex escape sequence
              @escape=PATINDEX('%\x[0-9a-f][0-9a-f][0-9a-f][0-9a-f]%', @token collate SQL_Latin1_General_CP850_Bin)
              IF @escape>0 --if there is one
                BEGIN
                  WHILE @index<4 --there are always four digits to a \x sequence   
                    BEGIN
                      SELECT --determine its value
                        @result=@result+POWER(16, @index)
                        *(CHARINDEX(SUBSTRING(@token, @escape+2+3-@index, 1),
                                    @characters)-1), @index=@index+1 ;
             
                    END
                    -- and replace the hex sequence by its unicode value
                  SELECT @token=STUFF(@token, @escape, 6, NCHAR(@result))
                END
            END
          --now store the string away 
          INSERT INTO @Strings (StringValue) SELECT @token
          -- and replace the string with a token
          SELECT @JSON=STUFF(@json, @start, @end+1,
                        '@string'+CONVERT(NCHAR(5), @@identity))
        END
      -- all strings are now removed. Now we find the first leaf.  
      WHILE 1=1  --forever until there is nothing more to do
      BEGIN
     
      SELECT @Parent_ID=@Parent_ID+1
      --find the first object or list by looking for the open bracket
      SELECT @FirstObject=PATINDEX('%[{[[]%', @json collate SQL_Latin1_General_CP850_Bin)--object or array
      IF @FirstObject = 0 BREAK
      IF (SUBSTRING(@json, @FirstObject, 1)='{') 
        SELECT @NextCloseDelimiterChar='}', @type='object'
      ELSE 
        SELECT @NextCloseDelimiterChar=']', @type='array'
      SELECT @OpenDelimiter=@firstObject
      WHILE 1=1 --find the innermost object or list...
        BEGIN
          SELECT
            @lenJSON=LEN(@JSON+'|')-1
      --find the matching close-delimiter proceeding after the open-delimiter
          SELECT
            @NextCloseDelimiter=CHARINDEX(@NextCloseDelimiterChar, @json,
                                          @OpenDelimiter+1)
      --is there an intervening open-delimiter of either type
          SELECT @NextOpenDelimiter=PATINDEX('%[{[[]%',
                 RIGHT(@json, @lenJSON-@OpenDelimiter)collate SQL_Latin1_General_CP850_Bin)--object
          IF @NextOpenDelimiter=0 
            BREAK
          SELECT @NextOpenDelimiter=@NextOpenDelimiter+@OpenDelimiter
          IF @NextCloseDelimiter<@NextOpenDelimiter 
            BREAK
          IF SUBSTRING(@json, @NextOpenDelimiter, 1)='{' 
            SELECT @NextCloseDelimiterChar='}', @type='object'
          ELSE 
            SELECT @NextCloseDelimiterChar=']', @type='array'
          SELECT @OpenDelimiter=@NextOpenDelimiter
        END
      ---and parse out the list or Name/value pairs
      SELECT
        @contents=SUBSTRING(@json, @OpenDelimiter+1,
                            @NextCloseDelimiter-@OpenDelimiter-1)
      SELECT
        @JSON=STUFF(@json, @OpenDelimiter,
                    @NextCloseDelimiter-@OpenDelimiter+1,
                    '@'+@type+CONVERT(NCHAR(5), @Parent_ID))
      WHILE (PATINDEX('%[A-Za-z0-9@+.e]%', @contents collate SQL_Latin1_General_CP850_Bin))<>0 
        BEGIN
          IF @Type='object' --it will be a 0-n list containing a string followed by a string, number,boolean, or null
            BEGIN
              SELECT
                @SequenceNo=0,@end=CHARINDEX(':', ' '+@contents)--if there is anything, it will be a string-based Name.
              SELECT  @start=PATINDEX('%[^A-Za-z@][@]%', ' '+@contents collate SQL_Latin1_General_CP850_Bin)--AAAAAAAA
              SELECT @token=RTrim(Substring(' '+@contents, @start+1, @End-@Start-1)),
                @endofName=PATINDEX('%[0-9]%', @token collate SQL_Latin1_General_CP850_Bin),
                @param=RIGHT(@token, LEN(@token)-@endofName+1)
              SELECT
                @token=LEFT(@token, @endofName-1),
                @Contents=RIGHT(' '+@contents, LEN(' '+@contents+'|')-@end-1)
              SELECT  @Name=StringValue FROM @strings
                WHERE string_id=@param --fetch the Name
            END
          ELSE 
            SELECT @Name=null,@SequenceNo=@SequenceNo+1 
          SELECT
            @end=CHARINDEX(',', @contents)-- a string-token, object-token, list-token, number,boolean, or null
                IF @end=0
            --HR Engineering notation bugfix start
              IF ISNUMERIC(@contents) = 1
            SELECT @end = LEN(@contents) + 1
              Else
            --HR Engineering notation bugfix end 
          SELECT  @end=PATINDEX('%[A-Za-z0-9@+.e][^A-Za-z0-9@+.e]%', @contents+' ' collate SQL_Latin1_General_CP850_Bin) + 1
           SELECT
            @start=PATINDEX('%[^A-Za-z0-9@+.e][A-Za-z0-9@+.e]%', ' '+@contents collate SQL_Latin1_General_CP850_Bin)
          --select @start,@end, LEN(@contents+'|'), @contents  
          SELECT
            @Value=RTRIM(SUBSTRING(@contents, @start, @End-@Start)),
            @Contents=RIGHT(@contents+' ', LEN(@contents+'|')-@end)
          IF SUBSTRING(@value, 1, 7)='@object' 
            INSERT INTO @hierarchy
              (Name, SequenceNo, Parent_ID, StringValue, Object_ID, ValueType)
              SELECT @Name, @SequenceNo, @Parent_ID, SUBSTRING(@value, 8, 5),
                SUBSTRING(@value, 8, 5), 'object' 
          ELSE 
            IF SUBSTRING(@value, 1, 6)='@array' 
              INSERT INTO @hierarchy
                (Name, SequenceNo, Parent_ID, StringValue, Object_ID, ValueType)
                SELECT @Name, @SequenceNo, @Parent_ID, SUBSTRING(@value, 7, 5),
                  SUBSTRING(@value, 7, 5), 'array' 
            ELSE 
              IF SUBSTRING(@value, 1, 7)='@string' 
                INSERT INTO @hierarchy
                  (Name, SequenceNo, Parent_ID, StringValue, ValueType)
                  SELECT @Name, @SequenceNo, @Parent_ID, StringValue, 'string'
                  FROM @strings
                  WHERE string_id=SUBSTRING(@value, 8, 5)
              ELSE 
                IF @value IN ('true', 'false') 
                  INSERT INTO @hierarchy
                    (Name, SequenceNo, Parent_ID, StringValue, ValueType)
                    SELECT @Name, @SequenceNo, @Parent_ID, @value, 'boolean'
                ELSE
                  IF @value='null' 
                    INSERT INTO @hierarchy
                      (Name, SequenceNo, Parent_ID, StringValue, ValueType)
                      SELECT @Name, @SequenceNo, @Parent_ID, @value, 'null'
                  ELSE
                    IF PATINDEX('%[^0-9]%', @value collate SQL_Latin1_General_CP850_Bin)>0 
                      INSERT INTO @hierarchy
                        (Name, SequenceNo, Parent_ID, StringValue, ValueType)
                        SELECT @Name, @SequenceNo, @Parent_ID, @value, 'real'
                    ELSE
                      INSERT INTO @hierarchy
                        (Name, SequenceNo, Parent_ID, StringValue, ValueType)
                        SELECT @Name, @SequenceNo, @Parent_ID, @value, 'int'
          if @Contents=' ' Select @SequenceNo=0
        END
      END
    INSERT INTO @hierarchy (Name, SequenceNo, Parent_ID, StringValue, Object_ID, ValueType)
      SELECT '-',1, NULL, '', @Parent_ID-1, @type
    --
       RETURN
    END

所以这个函数返回一个包含输入 JSON 的所有元素的表，它可以工作，但现在我尝试解析一个非常大的 json，如下所示：

[https://www.dropbox.com/scl/fi/fh69qiigfkfu0v7t67a4b/example-json.txt?rlkey=bvs3cw9wbxlwo84mnldjr4gv0&dl=0][1]

我减少了示例 json，因为超出了允许的最大长度。但该函数需要花费很多分钟来解析所有 json。我该如何解决？