Finds top N execution plans in cache that took the most time to complete, extracts statistics with low sampling with changed rows (and other filtering), and issues UPDATE STATISTIC commands for each. Meant to be run in high frequency on busy systems. Optionally add NORECOMPUTE to stop SQL Server from auto-updating managed statistics.

Adaptive Statistics Update.sql

/* To persist statistics and disallow engine rebuilding with default sampling, set @WithNoRecompute = 1 */
DECLARE @WithNoRecompute BIT		 = 1
		,@NoRecomputeSQL VARCHAR(50) = '';

IF @WithNoRecompute = 1
BEGIN
	SET @NoRecomputeSQL = ',NORECOMPUTE';
END;

DROP TABLE IF EXISTS #Temp;

DECLARE @Count INT = 1000;

DECLARE @plans TABLE
(
	query_text			  NVARCHAR(MAX)
	,o_name				  sysname
	,execution_plan		  XML
	,last_execution_time  DATETIME
	,execution_count	  BIGINT
	,total_worker_time	  BIGINT
	,total_physical_reads BIGINT
	,total_logical_reads  BIGINT
);

DECLARE @lookups TABLE
(
	table_name	sysname
	,index_name sysname
	,index_cols NVARCHAR(MAX)
);

WITH query_stats AS
(
	SELECT	TOP (@Count)
			dm_exec_query_stats.sql_handle
			,dm_exec_query_stats.plan_handle
			,SUM(total_dop) AS total_dop
			,MAX(dm_exec_query_stats.last_execution_time) AS last_execution_time
			,SUM(dm_exec_query_stats.execution_count) AS execution_count
			,SUM(dm_exec_query_stats.total_worker_time) AS total_worker_time
			,SUM(dm_exec_query_stats.total_physical_reads) AS total_physical_reads
			,SUM(dm_exec_query_stats.total_logical_reads) AS total_logical_reads
	FROM	sys.dm_exec_query_stats
	GROUP BY
			dm_exec_query_stats.sql_handle
			,dm_exec_query_stats.plan_handle
	ORDER BY
			execution_count DESC
)
SELECT	TOP (@Count)
		sql_text.text
		,DB_NAME(query_plan.dbid) AS DatabaseName
		,query_stats.total_dop
		,CASE
			 WHEN sql_text.objectid IS NOT NULL THEN ISNULL(OBJECT_NAME(sql_text.objectid, sql_text.dbid), 'Unresolved')
			 ELSE CAST('Ad-hoc\Prepared' AS sysname)
		 END AS QueryType
		,query_plan.query_plan
		,query_stats.last_execution_time
		,query_stats.execution_count
		,query_stats.total_worker_time
		,query_stats.total_physical_reads
		,query_stats.total_logical_reads
INTO	#Temp
FROM	query_stats
		CROSS APPLY sys.dm_exec_sql_text(query_stats.sql_handle) AS sql_text
		CROSS APPLY sys.dm_exec_query_plan(query_stats.plan_handle) AS query_plan
WHERE	query_plan.query_plan IS NOT NULL
ORDER BY
		query_stats.total_worker_time DESC;

DECLARE @sql				NVARCHAR(MAX)
		,@SamplingPercent	DECIMAL(5, 2)
		,@LastUpdated		DATETIME
		,@TableName			sysname
		,@StatName			sysname
		,@PercentDataChange DECIMAL(8, 2)
		,@RowCount			VARCHAR(100)
		,@Message			VARCHAR(150);

DECLARE db_cursor CURSOR FAST_FORWARD FOR 
WITH XMLNAMESPACES (DEFAULT 'http://schemas.microsoft.com/sqlserver/2004/07/showplan')
SELECT	SQLStatement
		,SamplingPercent
		,MAX(LastUpdate) AS MaxUpdate
		,TableName
		,StatisticsName
		,SUM(PercentDataChange) AS PercentDataChange
		,TableRows
FROM	(
			SELECT	DISTINCT
					'UPDATE STATISTICS ' + x.value('@Schema', 'sysname') + '.' + x.value('@Table', 'sysname') + ' '
					+ x.value('@Statistics', 'sysname') + ' WITH SAMPLE '
					+ CASE
						  WHEN TableRows <= 100000 THEN '100'	/* 100,000 */
						  WHEN TableRows <= 1000000 THEN '80'	/* 1,000,000 */
						  WHEN TableRows <= 5000000 THEN '50'	/* 5,000,000 */
						  WHEN TableRows <= 10000000 THEN '30'	/* 10,000,000 */
						  WHEN TableRows <= 100000000 THEN '20' /* 100,000,000 */
						  WHEN TableRows <= 500000000 THEN '10' /* 500,000,000 */
						  ELSE '5'								/* > 500,000,000 */
					  END + ' PERCENT' + @NoRecomputeSQL AS SQLStatement
					,CEILING(((sp.rows_sampled * 1.0) / (rows * 1.0)) * 100) AS SamplingPercent
					,sp.last_updated AS LastUpdate
					,x.value('@Table', 'sysname') AS TableName
					,x.value('@Statistics', 'sysname') AS StatisticsName
					,CASE
						 WHEN TableRows = 0 THEN 0
						 ELSE (sp.modification_counter * 1.0) / tr.TableRows
					 END AS PercentDataChange
					,tr.TableRows
			FROM	#Temp t
					CROSS APPLY t.query_plan.nodes('//OptimizerStatsUsage/StatisticsInfo') AS p(x)
					CROSS APPLY (
									SELECT	SUM(ps.row_count) AS TableRows
									FROM	sys.dm_db_partition_stats ps
									WHERE	ps.object_id = OBJECT_ID(PARSENAME(x.value('@Schema', 'sysname'), 1) + '.'
																	 + PARSENAME(x.value('@Table', 'sysname'), 1)
																	)
											AND ps.index_id IN (0, 1)
								) AS tr
					INNER JOIN sys.stats AS ss ON ss.object_id = OBJECT_ID(PARSENAME(x.value('@Schema', 'sysname'), 1)
																		   + '.'
																		   + PARSENAME(x.value('@Table', 'sysname'), 1)
																		  )
												  AND	ss.name = PARSENAME(x.value('@Statistics', 'sysname'), 1)
					CROSS APPLY sys.dm_db_stats_properties(ss.object_id, ss.stats_id) sp
			WHERE	1 = 1
					AND CEILING(((sp.rows_sampled * 1.0) / (rows * 1.0)) * 100) < CASE
																					  WHEN TableRows <= 100000 THEN '100'	/* 100,000 */
																					  WHEN TableRows <= 1000000 THEN '80'	/* 1,000,000 */
																					  WHEN TableRows <= 5000000 THEN '50'	/* 5,000,000 */
																					  WHEN TableRows <= 10000000 THEN '30'	/* 10,000,000 */
																					  WHEN TableRows <= 100000000 THEN '20' /* 100,000,000 */
																					  WHEN TableRows <= 500000000 THEN '10' /* 500,000,000 */
																					  ELSE '5'								/* > 500,000,000 */
																				  END
					AND (
							sp.modification_counter > 10000
							OR	DATEDIFF(HOUR, sp.last_updated, GETDATE()) > 24
						)
		) t
GROUP BY
		SQLStatement
		,SamplingPercent
		,TableName
		,StatisticsName
		,TableRows
ORDER BY
		PercentDataChange DESC;

OPEN db_cursor;

FETCH NEXT FROM db_cursor
INTO @sql
	 ,@SamplingPercent
	 ,@LastUpdated
	 ,@TableName
	 ,@StatName
	 ,@PercentDataChange
	 ,@RowCount;

WHILE @@FETCH_STATUS = 0
BEGIN
	DECLARE @Timestamp DATETIME2(3) = SYSDATETIME();

	SET @Message = 'Start Updating Stat...' + @TableName + ' ' + @StatName + '. ' + CAST(@SamplingPercent AS VARCHAR)
				   + ': ' + CONVERT(VARCHAR, @Timestamp, 120);

	RAISERROR(@Message, 0, 1) WITH NOWAIT;

	SET @Message = CAST(@SamplingPercent AS VARCHAR) + ' sampling. Last updated ' + CONVERT(VARCHAR, @LastUpdated, 120);

	RAISERROR(@Message, 0, 1) WITH NOWAIT;

	BEGIN TRY
		EXEC sp_executesql @sql;

		SET @Message = 'Stat Updated ' + @TableName + ' ' + @StatName + '. Seconds Elapsed: '
					   + CAST(DATEDIFF(SECOND, @Timestamp, SYSDATETIME()) AS VARCHAR);

		RAISERROR(@Message, 0, 1) WITH NOWAIT;
	END TRY
	BEGIN CATCH
		SET @Message = 'ERROR updating ' + @TableName + ' ' + @StatName + ': ' + ERROR_MESSAGE();

		RAISERROR(@Message, 16, 1) WITH NOWAIT;
	END CATCH;

	-- Blank line for readability in output
	RAISERROR('', 0, 1) WITH NOWAIT;

	FETCH NEXT FROM db_cursor
	INTO @sql
		 ,@SamplingPercent
		 ,@LastUpdated
		 ,@TableName
		 ,@StatName
		 ,@PercentDataChange
		 ,@RowCount;
END;

CLOSE db_cursor;
DEALLOCATE db_cursor;