sp_estimated_rowsize_reduction_for_vardecimal (Transact-SQL MetaData) Definition

Please note: that the following source code is provided and copyrighted by Microsoft and is for educational purpose only.
The meta data is from an SQL 2012 Server.

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Definition:

sys.sp_estimated_rowsize_reduction_for_vardecimal(nvarchar @table_name)

MetaData:

 create procedure sys.sp_estimated_rowsize_reduction_for_vardecimal    
    @table_name nvarchar (776)  
as  
begin  
    set nocount on  
  
    --  Get the table ID.  
    declare @table_id int;  
    set @table_id = object_id(@table_name);  
  
    --  If we can't find an object with this name, or if it's not a user table, or if  
    --  it doesn't belong to this database, give up.  
    if (@table_id is null  
        or objectproperty(@table_id, 'IsUserTable') = 0  
        or not exists (select * from sys.tables where object_id = @table_id))  
    begin  
        raiserror(15388, -1, -1, @table_name);  
        return @@error;  
    end;  
  
    --  Get physical stats for the table.  
    create table #physical_stats(alloc_unit_type_desc nvarchar(60), record_count bigint, avg_record_size_in_bytes float);  
    insert into #physical_stats select alloc_unit_type_desc, record_count, avg_record_size_in_bytes from  
        sys.dm_db_index_physical_stats(db_id(), @table_id, objectproperty(@table_id, 'TableHasClustIndex'), 0, 'SAMPLED');  
  
    --  Get the table's size.  
    declare @table_size float;  
    select @table_size = sum(avg_record_size_in_bytes * record_count) from #physical_stats;  
  
    --  Get the row count.  
    declare @row_count bigint;  
    select @row_count = sum(record_count) from #physical_stats where alloc_unit_type_desc = 'IN_ROW_DATA';  
  
    --  Now estimate the average savings per row.  
    declare @avg_savings float;  
    exec sys.sp_decimal_estimate_savings_for_table @table_id, @avg_savings output;  
  
    declare @avg_rowlen_fixed_format float, @avg_rowlen_vardecimal_format float;  
    if (@row_count > 0)  
    begin  
        --  Get the average row size.  
        declare @avg_row_size float;  
        set @avg_row_size = @table_size / @row_count;  
  
        --  If the table is not compressed, subtract the savings from the actual size to get the  
        --  compressed size. If the table is already compressed, add the savings to the actual  
        --  size to get the uncompressed size.  
        if (objectproperty(@table_id, 'tablehasvardecimalstorageformat') = 0)  
            select @avg_rowlen_fixed_format = @avg_row_size, @avg_rowlen_vardecimal_format = @avg_row_size - @avg_savings;  
        else  
            select @avg_rowlen_fixed_format = @avg_row_size + @avg_savings, @avg_rowlen_vardecimal_format = @avg_row_size;  
    end  
    else  
    begin  
        select @avg_rowlen_fixed_format = 0, @avg_rowlen_vardecimal_format = 0;  
    end;  
      
    --  Select the result set.   
    select cast(@avg_rowlen_fixed_format as decimal(12, 2)) as avg_rowlen_fixed_format,  
        cast(@avg_rowlen_vardecimal_format as decimal(12, 2)) as avg_rowlen_vardecimal_format,  
        @row_count as row_count;  
end;