Friday, 11 September 2015

SQL SERVER – Who Dropped Table or Database?

I used to run a series on Hero’s and Sherlock Holmes is one of my favorite. There is always a need to get to the bottom of the problem statement and whether you are a developer or a DBA, at least once you might have been asked one of the following “Who” question after a disaster.
  • Who dropped table in the database? From which application? When?
  • Who dropped database? What was the date and time?
  • Who created database on production server?
  • Who altered the database?
  • Who dropped the schema?
  • Who altered the schema?
And there are many other similar questions. Generally rich companies have auditing enabled and they have many tools which might be capturing all DDLs via either Auditing or via 3rd party tools.  Many of DBAs and developer don’t know that there is a default trace which runs in the background in every SQL Server installation
Here are few usage of default traces which are via SSMS.
Let’s look at the events captured by the default trace.
SELECT DISTINCT Trace.Event_ID, TraceEvents.NAME AS Event_Desc
FROM   ::fn_trace_geteventinfo(1) Trace
,sys.trace_events TraceEvents
WHERE Trace.eventID = TraceEvents.trace_event_id
Here is what we would get in SQL Server 2014
Event_ID Event_Desc
18 Audit Server Starts And Stops
20 Audit Login Failed
22 ErrorLog
46 Object:Created
47 Object:Deleted
55 Hash Warning
69 Sort Warnings
79 Missing Column Statistics
80 Missing Join Predicate
81 Server Memory Change
92 Data File Auto Grow
93 Log File Auto Grow
94 Data File Auto Shrink
95 Log File Auto Shrink
102 Audit Database Scope GDR Event
103 Audit Schema Object GDR Event
104 Audit Addlogin Event
105 Audit Login GDR Event
106 Audit Login Change Property Event
108 Audit Add Login to Server Role Event
109 Audit Add DB User Event
110 Audit Add Member to DB Role Event
111 Audit Add Role Event
115 Audit Backup/Restore Event
116 Audit DBCC Event
117 Audit Change Audit Event
152 Audit Change Database Owner
153 Audit Schema Object Take Ownership Event
155 FT:Crawl Started
156 FT:Crawl Stopped
164 Object:Altered
167 Database Mirroring State Change
175 Audit Server Alter Trace Event
218 Plan Guide Unsuccessful
As we can see there are various interesting events. Object:Altered, Object:Created and Object:Deleted can help us in identifying who dropped, altered or created any object. Once we get event class ID for the event of interest, we can use below query and replace the Event class ID.
-- read all available traces.
DECLARE @current VARCHAR(500);
DECLARE @start VARCHAR(500);
DECLARE @indx INT;
SELECT @current = path
FROM sys.traces
WHERE is_default = 1;
SET @current = REVERSE(@current)
SELECT @indx = PATINDEX('%\%', @current)
SET @current = REVERSE(@current)
SET @start = LEFT(@current, LEN(@current) - @indx) + '\log.trc';
-- CHNAGE FILER AS NEEDED
SELECT *
FROM::fn_trace_gettable(@start, DEFAULT)
WHERE EventClass IN (92,93) -- growth event
ORDER BY StartTime DESC
In above, I have used EventClass 92 and 93 to track database auto-growth events. Here is the query to find who dropped / created or altered object in database or database itself.
-- read all available traces.
DECLARE @current VARCHAR(500);
DECLARE @start VARCHAR(500);
DECLARE @indx INT;
SELECT @current = path
FROM sys.traces
WHERE is_default = 1;
SET @current = REVERSE(@current)
SELECT @indx = PATINDEX('%\%', @current)
SET @current = REVERSE(@current)
SET @start = LEFT(@current, LEN(@current) - @indx) + '\log.trc';
-- CHNAGE FILER AS NEEDED
SELECT CASE EventClass
WHEN 46 THEN 'Object:Created'
WHEN 47 THEN 'Object:Deleted'
WHEN 164 THEN 'Object:Altered'
END, DatabaseName, ObjectName, HostName, ApplicationName, LoginName, StartTime
FROM::fn_trace_gettable
(@start, DEFAULT)
WHERE EventClass IN (46,47,164) AND EventSubclass = 0 AND DatabaseID <> 2
ORDER BY StartTime DESC
Have you ever heard of someone being fired based on such auditing?

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