sys.dm_exec_plan_attributes (Transact-SQL)

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. For more information, see Query Tuning Recommendations.

Evaluating Set Options

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

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

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