Skip to main content

Bug in Microsoft Management Data Warehouse (MDW).

For those who use MDW and complain about the bug in the report Disk Usage Collection Set - Database, I updated the query so that it shows now the correct data. The bug is very consistent: it's in there from 2008 R2 and still there.

Take a look at the report:

As you can see the report shows more than 8 GB but in the data below you can see that the database size is no more than 4,3 GB. 

 Someone just made a programming error at Microsoft and unknown on what the field values mean in MDW just mixed up some numbers. I have to admit that it is not easy :-)

 I rewrote the query after comparing the values with a real database and added the log value. Now it is to Microsoft to add it. 

Here's the code (I highlighted the changes):


exec sp_executesql @stmt=N'BEGIN TRY
DECLARE @snapshot_id int
SELECT TOP 1 @snapshot_id = snapshot_id FROM (

SELECT DISTINCT TOP 100 d.snapshot_id
FROM snapshots.disk_usage d, core.snapshots ss
WHERE ss.instance_name = @ServerName
AND ss.snapshot_id = d.snapshot_id
ORDER BY d.snapshot_id DESC

) AS q
ORDER BY snapshot_id ASC


SELECT
            CONVERT (datetime, SWITCHOFFSET (CAST (d.collection_time AS datetimeoffset), ''+00:00'')) AS collection_time,
            d.snapshot_id,
            ((convert(dec (15,2),d.dbsize) + convert(dec(15,2),d.logsize)) * 8192 / 1048576.0) AS ''database_size_mb'',
            (convert(dec(15,2),d.logsize) * 8192 / 1048576.0) AS ''log_size_mb'',
            ((d.usedpages - (d.usedpages - d.pages))  * 8192 / 1048576.0) AS ''data_size_mb'',
            ((d.reservedpages - d.usedpages) * 8192 / 1048576.0) AS ''reserved_mb'',
            (
                  case 
                        when d.dbsize >= d.reservedpages
                        then (convert (dec (15,2),d.dbsize) - convert (dec (15,2),d.reservedpages)) * 8192 / 1048576.0 
                  else 0 
                  end) AS ''unallocated_space_mb'',
            ((d.usedpages - d.pages) * 8192 / 1048576.0) AS ''index_mb''
FROM snapshots.disk_usage d, core.snapshots ss
WHERE database_name=@SelectedDatabaseName
  AND d.snapshot_id >= @snapshot_id
  AND ss.instance_name = @ServerName
  AND d.snapshot_id = ss.snapshot_id
ORDER BY collection_time

END TRY
BEGIN CATCH

SELECT
null AS collection_time,
ERROR_NUMBER() AS snapshot_id,
ERROR_SEVERITY() AS database_size_mb,
ERROR_STATE() AS reserved_mb,
ERROR_MESSAGE() AS unallocated_space_mb,
1 AS index_mb

END CATCH',@params=N'@ServerName NVarChar(max), @SelectedDatabaseName NVarChar(max)',@ServerName=N'MyServer',@SelectedDatabaseName=N'MDW'


I verified it with the real database data and it is 100% correct. 

This change wasn't too difficult. Maybe it can be added in a Cummulative Update for SQL Server versions 2008 R2 to 2012.


Labels:

Comments

Post a Comment

Popular posts from this blog

Privacy and the liberty to express yourself on LinkedIn

Unaware that LinkedIn has such a strong filtering policy that it does not allow me posting a completely innocent post on a Chinese extreme photography website I tried to post the following: "As an Mpx lover I was suprised to find out that the M from Million is now replaced by the B from Billion. This picture is 24 Bpx! Yes you read this well, 24 billion pixels.  Searching on the picture I stumbled on a fellow Nikon lover. If you want to search for him yourself you can find him here: http://www.bigpixel.cn/t/5834170785f26b37002af46a " In my eyes nothing is wrong with this post, but LinkedIn considers it as offending. I changed the lover words, but I could not post it.  Even taking a picture and post it will not let this pass:  Or my critical post on LinkedIn crazy posting policy: it will not pass and I cannot post it.  The technology LinkedIn shows here is an example what to expect in the near future.  Newspapers will have a unified re...
Post a Comment
Read more

How to run SQL Server 2016 with In-Databasse R on Windows 2016 CTP5

For those who like me tried to run SQL Server 2016 with In-Database R might have run into the same problem as me: In-Database R or the LaunchPad service gives a timeout and won't start. I did several clean installations with different configuration options - for instance I like to put my data on another disk than the system disk - but in the end I tried to do the next, next, next, finish install to see if it something in the setup options is hard coded in there (yes, it happens developers!). For some reason this problem is related to Windows 2016 and not on Windows 2012R2 and I hope the SQL Server team will soon resolve these issues because they are in one word a bit sloppy.  There are 2 issues (maybe even 3 so I give this one also):  The R setup does not create the ExtensibilityLog directory in the "C:\Program Files\Microsoft SQL Server\MSSQL13.MSSQLSERVER\MSSQL\Log" directory The R setup sets the number of users in the SQL Server Launchpad service to 0 it is pos...
Post a Comment
Read more

Truncate a table in SQL Server and nobody will ever see it....

Today I ran into a very strange problem. I was doing an audit because a client lost 32 billion records in a table and he wanted to know "Who did it!". They did not use auditing because it had a too large impact on performance. The server and instance was not restarted so the DMV's were still available with data.  I presumed there were two options how the data could have been lost and so quickly: run a TRUNCATE TABLE. Very fast and and in less than a second your table is unrecoverable empty  Switch a partition out into a temporary table and just truncate the original table. Yes it happens and the effect is the same: nothing!  So I ran this query to collect the last queries: SELECT t.TEXT QueryName, s.execution_count AS ExecutionCount, s.max_elapsed_time AS MaxElapsedTime, ISNULL(s.total_elapsed_time / s.execution_count, 0) AS AvgElapsedTime, s.creation_time AS LogCreatedOn FROM sys.dm_exec_query_stats s CROSS APPLY sys.dm_exec_sql_text( s.sql_handle ) t WHERE t.TE...
Post a Comment
Read more