Missing Column Statistics Event Class
The Missing Column Statistics event class indicates that column statistics that could have been useful for the optimizer are not available.
By monitoring the Missing Column Statistics event class, you can determine if there are statistics missing for a column used by a query. This can cause the optimizer to choose a less efficient query plan than expected.
Missing Column Statistics Event Class Data Columns
Data column name |
Data type |
Description |
Column ID |
Filterable |
|---|---|---|---|---|
ApplicationName |
nvarchar |
Name of the client application that created the connection to an instance of SQL Server. This column is populated with the values passed by the application rather than the displayed name of the program. |
10 |
Yes |
ClientProcessID |
int |
ID assigned by the host computer to the process where the client application is running. This data column is populated if the client provides the client process ID. |
9 |
Yes |
DatabaseID |
int |
ID of the database specified by the USE database statement or the default database if no USE database statement has been issued for a given instance. SQL Server Profiler displays the name of the database if the ServerName data column is captured in the trace and the server is available. Determine the value for a database by using the DB_ID function. |
3 |
Yes |
DatabaseName |
nvarchar |
Name of the database in which the user statement is running. |
35 |
Yes |
EventClass |
int |
Type of event=79. |
27 |
No |
EventSequence |
int |
Sequence of a given event within the request. |
51 |
No |
GroupID |
int |
ID of the workload group where the SQL Trace event fires. |
66 |
Yes |
HostName |
nvarchar |
Name of the computer on which the client is running. This data column is populated if the client provides the host name. To determine the host name, use the HOST_NAME function. |
8 |
Yes |
IsSystem |
int |
Indicates whether the event occurred on a system process or a user process. 1 = system, 0 = user. |
60 |
Yes |
LoginName |
nvarchar |
Name of the login of the user (either SQL Server security login or the Microsoft Windows login credentials in the form of DOMAIN\username). |
11 |
Yes |
LoginSid |
image |
Security identification number (SID) of the logged-in user. You can find this information in the sys.server_principals catalog view. Each SID is unique for each login in the server. |
41 |
Yes |
NTDomainName |
nvarchar |
Windows domain to which the user belongs. |
7 |
Yes |
NTUserName |
nvarchar |
Windows user name. |
6 |
Yes |
RequestID |
int |
ID of the request containing the statement. |
49 |
Yes |
ServerName |
nvarchar |
Name of the instance of SQL Server being traced. |
26 |
No |
SessionLoginName |
nvarchar |
Login name of the user who originated the session. For example, if you connect to SQL Server using Login1 and execute a statement as Login2, SessionLoginName shows Login1 and LoginName shows Login2. This column displays both SQL Server and Windows logins. |
64 |
Yes |
SPID |
int |
ID of the session on which the event occurred. |
12 |
Yes |
StartTime |
datetime |
Time at which the event started, if available. |
14 |
Yes |
TextData |
ntext |
List of the columns with missing statistics. |
1 |
Yes |
TransactionID |
bigint |
System-assigned ID of the transaction. |
4 |
Yes |
XactSequence |
bigint |
Token that describes the current transaction. |
50 |
Yes |
Zobacz także
Odwołanie
sp_trace_setevent (Transact-SQL)
CREATE STATISTICS (Transact-SQL)