sp_clean_db_file_free_space (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_clean_db_file_free_space(nvarchar @dbname
, int @fileid
, int @cleaning_delay)

MetaData:

   
create procedure sys.sp_clean_db_file_free_space (  
    @dbname sysname,  
    @fileid int,  
    @cleaning_delay int = 0)  
as  
begin  
    SET NOCOUNT ON  
    declare @quoted_dbname nvarchar(258)  
    set @quoted_dbname=QUOTENAME(@dbname)  
  
    declare @flush nvarchar(1024)  
    set @flush =  'USE ' + @quoted_dbname +  ' checkpoint'  
    --   
    --  Parameter check  
    --  @dbname  
    --   
    if (db_id(@dbname) is null)  
    begin  
        RAISERROR(15010, 16, -1, @quoted_dbname)  
        return (1)  
    end  
  
    --   
    --  security check  
    --  only db_owner can execute this  
    --   
    declare @check nvarchar(1024)  
    set @check = 'USE ' + @quoted_dbname +  
    'if (is_member (''db_owner'') != 1)   
    begin  
        raiserror(14260, 16, -1)  
    end'  
    exec (@check)  
    if @@error =14260  
    begin  
        return (1)  
    end  
  
    declare @page int  
    set @page = 0  
    declare @dbid int  
  
    create table #continueclean (  
        fileid int,  
        page int)  
    declare @sql as nvarchar(1024)  
    set @sql = 'insert #continueclean (fileid, page) select file_id, size from ' + @quoted_dbname + '.sys.database_files where file_id=' + cast(@fileid as nvarchar) + ' and type=0'  
    exec (@sql)  
  
    select @dbid=db_id(@dbname)  
    while exists(select * from #continueclean where fileid = @fileid and page > @page)  
    begin  
        dbcc cleanpage(@dbid , @fileid, @page)  
        set @page = @page+1  
  
        --  delay execution to throttle impact on system  
        if (@cleaning_delay > 0)  
            waitfor delay @cleaning_delay  
  
        --  checkpoint periodically   
        if @page % 10000 = 0  
        begin  
            exec (@flush)  
        end  
  
        set @sql = 'update #continueclean set fileid=file_id, page=size from ' + @quoted_dbname + '.sys.database_files where file_id=' + cast(@fileid as nvarchar) + ' and type=0'  
        exec (@sql)  
    end  
    drop table #continueclean  
    exec (@flush)  
    end