sys.dm_exec_text_query_plan
New: 12 December 2006
Returns the Showplan in text format for a Transact-SQL batch or for a specific statement within the batch. The query plan specified by the plan handle can either be cached or currently executing. This table-valued function is similar to sys.dm_exec_query_plan, but has the following differences:
- The output of the query plan is returned in text format.
- The output of the query plan is not limited in size.
- Individual statements within the batch can be specified.
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Transact-SQL Syntax Conventions
Syntax
sys.dm_exec_text_query_plan
(
plan_handle
, { statement_start_offset | 0 | DEFAULT }
, { statement_end_offset | -1 | DEFAULT }
)
Arguments
plan_handle
Uniquely identifies a query plan for a batch that is cached or is currently executing. plan_handle is varbinary(64).The plan handle can be obtained from the following dynamic management objects:
statement_start_offset | 0 | DEFAULT
Indicates, in bytes, the starting position of the query that the row describes within the text of its batch or persisted object. statement_start_offset is int. A value of 0 indicates the beginning of the batch. The default value is 0.The statement start offset can be obtained from the following dynamic management objects:
statement_end_offset | -1 | DEFAULT
Indicates, in bytes, the ending position of the query that the row describes within the text of its batch or persisted object.statement_start_offset is int.
A value of -1 indicates the end of the batch. The default value is -1.
Table Returned
| Column name | Data type | Description |
|---|---|---|
dbid |
smallint |
ID of the context database that was in effect when the Transact-SQL statement corresponding to this plan was compiled. For ad hoc and prepared batches, this column is null. Column is nullable. |
objectid |
int |
ID of the object (for example, stored procedure or user-defined function) for this query plan. For ad hoc and prepared batches, this column is null. Column is nullable. |
number |
smallint |
Numbered stored procedure integer. For example, a group of procedures for the orders application may be named orderproc;1, orderproc;2, and so on. For ad hoc and prepared batches, this column is null. Column is nullable. |
encrypted |
bit |
Indicates whether the corresponding stored procedure is encrypted. 0 = not encrypted 1 = encrypted Column is not nullable. |
query_plan |
nvarchar(max) |
Contains the compile-time Showplan representation of the query execution plan that is specified with plan_handle. The Showplan is in text format. One plan is generated for each batch that contains, for example ad hoc Transact-SQL statements, stored procedure calls, and user-defined function calls. Column is nullable. |
Remarks
Under the following conditions, no Showplan output is returned in the plan column of the returned table for sys.dm_exec_text_query_plan:
- If the query plan that is specified by using plan_handle has been evicted from the plan cache, the query_plan column of the returned table is null. For example, this condition may occur if there is a time delay between when the plan handle was captured and when it was used with sys.dm_exec_text_query_plan.
- Some Transact-SQL statements are not cached, such as bulk operation statements or statements containing string literals larger than 8 KB in size. Showplans for such statements cannot be retrieved by using sys.dm_exec_text_query_plan because they do not exist in the cache.
- If a Transact-SQL batch or stored procedure contains a call to a user-defined function or a call to dynamic SQL, for example using EXEC (string), the compiled XML Showplan for the user-defined function is not included in the table returned by sys.dm_exec_text_query_plan for the batch or stored procedure. Instead, you must make a separate call to sys.dm_exec_text_query_plan for the plan_handle that corresponds to the user-defined function.
When an ad hoc query uses simple or forced parameterization, the query_plan column will contain only the statement text and not the actual query plan. To return the query plan, call sys.dm_exec_text_query_plan for the plan handle of the prepared parameterized query. You can determine whether the query was parameterized by referencing the sql column of the sys.syscacheobjects view or the text column of the sys.dm_exec_sql_text dynamic management view. For more information about parameterization see, Simple Parameterization and Forced Parameterization.
Permissions
To execute sys.dm_exec_text_query_plan, a user must be a member of the sysadmin fixed server role or have the VIEW SERVER STATE permission on the server.
Examples
A. Retrieve the cached query plan for a slow-running Transact-SQL query or batch
If a Transact-SQL query or batch runs a long time on a particular connection to SQL Server, retrieve the execution plan for that query or batch to discover what is causing the delay. The following example shows how to retrieve the Showplan for a slow-running query or batch.
Note
To run this example, replace the values for session_id and plan_handle with values specific to your server.
First, retrieve the server process ID (SPID) for the process that is executing the query or batch by using the sp_who stored procedure:
USE master;
GO
EXEC sp_who;
GO
The result set that is returned by sp_who indicates that the SPID is 54. You can use the SPID with the sys.dm_exec_requests dynamic management view to retrieve the plan handle by using the following query:
USE master;
GO
SELECT * FROM sys.dm_exec_requests
WHERE session_id = 54;
GO
The table that is returned by sys.dm_exec_requests indicates that the plan handle for the slow-running query or batch is 0x06000100A27E7C1FA821B10600. The following example returns the query plan for the specified plan handle and uses the default values 0 and -1 to return all statements in the query or batch.
USE master;
GO
SELECT query_plan
FROM sys.dm_exec_text_query_plan (0x06000100A27E7C1FA821B10600,0,-1);
GO
B. Retrieve every query plan from the plan cache
To retrieve a snapshot of all query plans residing in the plan cache, retrieve the plan handles of all query plans in the cache by querying the sys.dm_exec_cached_plans dynamic management view. The plan handles are stored in the plan_handle column of sys.dm_exec_cached_plans. Then use the CROSS APPLY operator to pass the plan handles to sys.dm_exec_text_query_plan as follows. The Showplan output for each plan currently in the plan cache is in the query_plan column of the table that is returned.
USE master;
GO
SELECT *
FROM sys.dm_exec_cached_plans AS cp
CROSS APPLY sys.dm_exec_text_query_plan(cp.plan_handle, DEFAULT, DEFAULT);
GO
C. Retrieve every query plan for which the server has gathered query statistics from the plan cache
To retrieve a snapshot of all query plans for which the server has gathered statistics that currently reside in the plan cache, retrieve the plan handles of these plans in the cache by querying the sys.dm_exec_query_stats dynamic management view. The plan handles are stored in the plan_handle column of sys.dm_exec_query_stats. Then use the CROSS APPLY operator to pass the plan handles to sys.dm_exec_text_query_plan as follows. The Showplan output for each plan is in the query_plan column of the table that is returned.
USE master;
GO
SELECT * FROM sys.dm_exec_query_stats AS qs
CROSS APPLY sys.dm_exec_text_query_plan(qs.plan_handle, qs.statement_start_offset, qs.statement_end_offset);
GO
D. Retrieve information about the top five queries by average CPU time
The following example returns the query plans and average CPU time for the top five queries. The sys.dm_exec_text_query_plan function specifies the default values 0 and -1 to return all statements in the batch in the query plan.
SELECT TOP 5 total_worker_time/execution_count AS [Avg CPU Time],
Plan_handle, query_plan
FROM sys.dm_exec_query_stats AS qs
CROSS APPLY sys.dm_exec_text_query_plan(qs.plan_handle, 0, -1)
ORDER BY total_worker_time/execution_count DESC;
GO