sys.dm_exec_plan_attributes (Transact-SQL)

THIS TOPIC APPLIES TO:yesSQL Server (starting with 2008)noAzure SQL DatabasenoAzure SQL Data Warehouse noParallel Data Warehouse

Returns one row per plan attribute for the plan specified by the plan handle. You can use this table-valued function to get details about a particular plan, such as the cache key values or the number of current simultaneous executions of the plan.

Note

Some of the information returned through this function maps to the sys.syscacheobjects backward compatibility view.

Syntax

sys.dm_exec_plan_attributes ( plan_handle )  

Arguments

plan_handle
Uniquely identifies a query plan for a batch that has executed and whose plan resides in the plan cache. plan_handle is varbinary(64). The plan handle can be obtained from the sys.dm_exec_cached_plans dynamic management view.

Table Returned

Column name Data type Description
attribute varchar(128) Name of the attribute associated with this plan. The table immediately below this one lists the possible attributes, their data types, and their descriptions.
value sql_variant Value of the attribute that is associated with this plan.
is_cache_key bit Indicates whether the attribute is used as part of the cache lookup key for the plan.

From the above table, attribute can have the following values:

Attribute Data type Description
set_options int Indicates the option values that the plan was compiled with.
objectid int One of the main keys used for looking up an object in the cache. This is the object ID stored in sys.objects for database objects (procedures, views, triggers, and so on). For plans of type "Adhoc" or "Prepared", it is an internal hash of the batch text.
dbid int Is the ID of the database containing the entity the plan refers to.

For ad hoc or prepared plans, it is the database ID from which the batch is executed.
dbid_execute int For system objects stored in the Resource database, the database ID from which the cached plan is executed. For all other cases, it is 0.
user_id int Value of -2 indicates that the batch submitted does not depend on implicit name resolution and can be shared among different users. This is the preferred method. Any other value represents the user ID of the user submitting the query in the database.
language_id smallint ID of the language of the connection that created the cache object. For more information, see sys.syslanguages (Transact-SQL).
date_format smallint Date format of the connection that created the cache object. For more information, see SET DATEFORMAT (Transact-SQL).
date_first tinyint Date first value. For more information, see SET DATEFIRST (Transact-SQL).
status int Internal status bits that are part of the cache lookup key.
required_cursor_options int Cursor options specified by the user such as the cursor type.
acceptable_cursor_options int Cursor options that SQL Server may implicitly convert to in order to support the execution of the statement. For example, the user may specify a dynamic cursor, but the query optimizer is permitted to convert this cursor type to a static cursor.
inuse_exec_context int Number of currently executing batches that are using the query plan.
free_exec_context int Number of cached execution contexts for the query plan that are not being currently used.
hits_exec_context int Number of times the execution context was obtained from the plan cache and reused, saving the overhead of recompiling the SQL statement. The value is an aggregate for all batch executions so far.
misses_exec_context int Number of times that an execution context could not be found in the plan cache, resulting in the creation of a new execution context for the batch execution.
removed_exec_context int Number of execution contexts that have been removed because of memory pressure on the cached plan.
inuse_cursors int Number of currently executing batches containing one or more cursors that are using the cached plan.
free_cursors int Number of idle or free cursors for the cached plan.
hits_cursors int Number of times that an inactive cursor was obtained from the cached plan and reused. The value is an aggregate for all batch executions so far.
misses_cursors int Number of times that an inactive cursor could not be found in the cache.
removed_cursors int Number of cursors that have been removed because of memory pressure on the cached plan.
sql_handle varbinary(64) The SQL handle for the batch.
merge_action_type smallint The type of trigger execution plan used as the result of a MERGE statement.

0 indicates a non-trigger plan, a trigger plan that does not execute as the result of a MERGE statement, or a trigger plan that executes as the result of a MERGE statement that only specifies a DELETE action.

1 indicates an INSERT trigger plan that runs as the result of a MERGE statement.

2 indicates an UPDATE trigger plan that runs as the result of a MERGE statement.

3 indicates a DELETE trigger plan that runs as the result of a MERGE statement containing a corresponding INSERT or UPDATE action.

For nested triggers run by cascading actions, this value is the action of the MERGE statement that caused the cascade.

Permissions

On SQL Server requires VIEW SERVER STATE permission on the server.

On SQL Database Premium Tiers requires the VIEW DATABASE STATE permission in the database. On SQL Database Standard and Basic Tiers requires the SQL Database admin account.

Remarks

Set Options

Copies of the same compiled plan might differ only by the value in the set_options column. This indicates that different connections are using different sets of SET options for the same query. Using different sets of options is usually undesirable because it can cause extra compilations, less plan reuse, and plan cache inflation because of multiple copies of plans in the cache.

Evaluating Set Options

To translate the value returned in set_options to the options with which the plan was compiled, subtract the values from the set_options value, starting with the largest possible value, until you reach 0. Each value you subtract corresponds to an option that was used in the query plan. For example, if the value in set_options is 251, the options the plan was compiled with are ANSI_NULL_DFLT_ON (128), QUOTED_IDENTIFIER (64), ANSI_NULLS(32), ANSI_WARNINGS (16), CONCAT_NULL_YIELDS_NULL (8), Parallel Plan(2) and ANSI_PADDING (1).

Option Value
ANSI_PADDING 1
Parallel Plan 2
FORCEPLAN 4
CONCAT_NULL_YIELDS_NULL 8
ANSI_WARNINGS 16
ANSI_NULLS 32
QUOTED_IDENTIFIER 64
ANSI_NULL_DFLT_ON 128
ANSI_NULL_DFLT_OFF 256
NoBrowseTable

Indicates that the plan does not use a work table to implement a FOR BROWSE operation.
512
TriggerOneRow

Indicates that the plan contains single row optimization for AFTER trigger delta tables.
1024
ResyncQuery

Indicates that the query was submitted by internal system stored procedures.
2048
ARITH_ABORT 4096
NUMERIC_ROUNDABORT 8192
DATEFIRST 16384
DATEFORMAT 32768
LanguageID 65536
UPON

Indicates that the database option PARAMETERIZATION was set to FORCED when the plan was compiled.
131072
ROWCOUNT Applies To: SQL Server 2012 to SQL Server 2017

262144

Cursors

Inactive cursors are cached in a compiled plan so that the memory used to store the cursor can be reused by concurrent users of cursors. For example, suppose that a batch declares and uses a cursor without deallocating it. If there are two users executing the same batch, there will be two active cursors. Once the cursors are deallocated (potentially in different batches), the memory used to store the cursor is cached and not released. This list of inactive cursors is kept in the compiled plan. The next time a user executes the batch, the cached cursor memory will be reused and initialized appropriately as an active cursor.

Evaluating Cursor Options

To translate the value returned in required_cursor_options and acceptable_cursor_options to the options with which the plan was compiled, subtract the values from the column value, starting with the largest possible value, until you reach 0. Each value you subtract corresponds to a cursor option that was used in the query plan.

Option Value
None 0
INSENSITIVE 1
SCROLL 2
READ ONLY 4
FOR UPDATE 8
LOCAL 16
GLOBAL 32
FORWARD_ONLY 64
KEYSET 128
DYNAMIC 256
SCROLL_LOCKS 512
OPTIMISTIC 1024
STATIC 2048
FAST_FORWARD 4096
IN PLACE 8192
FOR select_statement 16384

Examples

A. Returning the attributes for a specific plan

The following example returns all plan attributes for a specified plan. The sys.dm_exec_cached_plans dynamic management view is queried first to obtain the plan handle for the specified plan. In the second query, replace <plan_handle> with a plan handle value from the first query.

SELECT plan_handle, refcounts, usecounts, size_in_bytes, cacheobjtype, objtype   
FROM sys.dm_exec_cached_plans;  
GO  
SELECT attribute, value, is_cache_key  
FROM sys.dm_exec_plan_attributes(<plan_handle>);  
GO  

B. Returning the SET options for compiled plans and the SQL handle for cached plans

The following example returns a value representing the options that each plan was compiled with. In addition, the SQL handle for all the cached plans is returned.

SELECT plan_handle, pvt.set_options, pvt.sql_handle  
FROM (  
    SELECT plan_handle, epa.attribute, epa.value   
    FROM sys.dm_exec_cached_plans   
        OUTER APPLY sys.dm_exec_plan_attributes(plan_handle) AS epa  
    WHERE cacheobjtype = 'Compiled Plan') AS ecpa   
PIVOT (MAX(ecpa.value) FOR ecpa.attribute IN ("set_options", "sql_handle")) AS pvt;  
GO  

See Also

Dynamic Management Views and Functions (Transact-SQL)
Execution Related Dynamic Management Views and Functions (Transact-SQL)
sys.dm_exec_cached_plans (Transact-SQL)
sys.databases (Transact-SQL)
sys.objects (Transact-SQL)