-- Azure SQL Database Diagnostic Information Queries
-- Glenn Berry 
-- Last Modified: September 1, 2020
-- https://glennsqlperformance.com/
-- https://sqlserverperformance.wordpress.com/
-- YouTube: https://bit.ly/2PkoAM1 
-- Twitter: GlennAlanBerry

-- Diagnostic Queries are available here
-- https://glennsqlperformance.com/resources/


-- If you like PowerShell, there is a very useful community solution for running these queries in an automated fashion
-- https://dbatools.io/

-- Invoke-DbaDiagnosticQuery
-- https://dbatools.io/functions/invoke-dbadiagnosticquery/


--******************************************************************************
--*   Copyright (C) 2020 Glenn Berry
--*   All rights reserved. 
--*
--*
--*   You may alter this code for your own *non-commercial* purposes. You may
--*   republish altered code as long as you include this copyright and give due credit. 
--*
--*
--*   THIS CODE AND INFORMATION ARE PROVIDED "AS IS" WITHOUT WARRANTY OF 
--*   ANY KIND, EITHER EXPRESSED OR IMPLIED, INCLUDING BUT NOT LIMITED 
--*   TO THE IMPLIED WARRANTIES OF MERCHANTABILITY AND/OR FITNESS FOR A
--*   PARTICULAR PURPOSE. 
--*
--******************************************************************************

-- Make sure you are connected a user database, rather than the master system database


-- Server level queries *******************************

-- SQL and OS Version information for current instance  (Query 1) (Version Info)
SELECT @@SERVERNAME AS [Server Name], @@VERSION AS [SQL Server and OS Version Info];
------

-- Azure SQL Database does not expose as much information as on-premises SQL Server does
													


-- Get logical instance-level configuration values for instance  (Query 2) (Configuration Values)
SELECT name, value, value_in_use, minimum, maximum, [description], is_dynamic, is_advanced
FROM sys.configurations WITH (NOLOCK)
ORDER BY name OPTION (RECOMPILE);
------

-- All of these settings are read-only in Azure SQL Database, so they are informational only



-- SQL Server NUMA Node information  (Query 3) (SQL Server NUMA Info)
SELECT node_id, node_state_desc, memory_node_id, processor_group, cpu_count, online_scheduler_count, 
       idle_scheduler_count, active_worker_count, avg_load_balance, resource_monitor_state
FROM sys.dm_os_nodes WITH (NOLOCK) 
WHERE node_state_desc <> N'ONLINE DAC' OPTION (RECOMPILE);
------

-- Gives you some useful information about the composition and relative load on your NUMA nodes
-- You want to see an equal number of schedulers on each NUMA node



-- Calculates average stalls per read, per write, and per total input/output for each database file  (Query 4) (IO Stalls by File)
SELECT DB_NAME(fs.database_id) AS [Database Name], CAST(fs.io_stall_read_ms/(1.0 + fs.num_of_reads) AS NUMERIC(16,1)) AS [avg_read_stall_ms],
CAST(fs.io_stall_write_ms/(1.0 + fs.num_of_writes) AS NUMERIC(16,1)) AS [avg_write_stall_ms],
CAST((fs.io_stall_read_ms + fs.io_stall_write_ms)/(1.0 + fs.num_of_reads + fs.num_of_writes) AS NUMERIC(16,1)) AS [avg_io_stall_ms],
fs.io_stall_read_ms, fs.num_of_reads, 
fs.io_stall_write_ms, fs.num_of_writes, fs.io_stall_read_ms + fs.io_stall_write_ms AS [io_stalls], fs.num_of_reads + fs.num_of_writes AS [total_io],
io_stall_queued_read_ms AS [Resource Governor Total Read IO Latency (ms)], io_stall_queued_write_ms AS [Resource Governor Total Write IO Latency (ms)]
FROM sys.dm_io_virtual_file_stats(null,null) AS fs
ORDER BY avg_io_stall_ms DESC OPTION (RECOMPILE);
------

-- Helps determine which database files on the entire instance have the most I/O bottlenecks
-- This can help you decide whether certain LUNs are overloaded and whether you might
-- want to move some files to a different location or perhaps improve your I/O performance
-- These latency numbers include all file activity against each SQL Server 
-- database file since SQL Server was last started



-- Get I/O utilization by database (Query 5) (IO Usage By Database)
WITH Aggregate_IO_Statistics
AS (SELECT DB_NAME(database_id) AS [Database Name],
    CAST(SUM(num_of_bytes_read + num_of_bytes_written) / 1048576 AS DECIMAL(12, 2)) AS [ioTotalMB],
    CAST(SUM(num_of_bytes_read ) / 1048576 AS DECIMAL(12, 2)) AS [ioReadMB],
    CAST(SUM(num_of_bytes_written) / 1048576 AS DECIMAL(12, 2)) AS [ioWriteMB]
    FROM sys.dm_io_virtual_file_stats(NULL, NULL) AS [DM_IO_STATS]
    GROUP BY database_id)
SELECT ROW_NUMBER() OVER (ORDER BY ioTotalMB DESC) AS [I/O Rank],
        [Database Name], ioTotalMB AS [Total I/O (MB)],
        CAST(ioTotalMB / SUM(ioTotalMB) OVER () * 100.0 AS DECIMAL(5, 2)) AS [Total I/O %],
        ioReadMB AS [Read I/O (MB)], 
		CAST(ioReadMB / SUM(ioReadMB) OVER () * 100.0 AS DECIMAL(5, 2)) AS [Read I/O %],
        ioWriteMB AS [Write I/O (MB)], 
		CAST(ioWriteMB / SUM(ioWriteMB) OVER () * 100.0 AS DECIMAL(5, 2)) AS [Write I/O %]
FROM Aggregate_IO_Statistics
ORDER BY [I/O Rank] OPTION (RECOMPILE);
------

-- Helps determine which database is using the most I/O resources on the instance


-- Get total buffer usage by database for current instance  (Query 6) (Total Buffer Usage by Database)
-- This make take some time to run on a busy instance
WITH AggregateBufferPoolUsage
AS
(SELECT DB_NAME(database_id) AS [Database Name], COUNT(page_id) AS [Page Count],
CAST(COUNT(*) * 8/1024.0 AS DECIMAL (10,2))  AS [CachedSize],
AVG(read_microsec) AS [Avg Read Time (microseconds)]
FROM sys.dm_os_buffer_descriptors WITH (NOLOCK)
GROUP BY DB_NAME(database_id))
SELECT ROW_NUMBER() OVER(ORDER BY CachedSize DESC) AS [Buffer Pool Rank], [Database Name], 
       CAST(CachedSize / SUM(CachedSize) OVER() * 100.0 AS DECIMAL(5,2)) AS [Buffer Pool Percent],
       [Page Count], CachedSize AS [Cached Size (MB)], [Avg Read Time (microseconds)]
FROM AggregateBufferPoolUsage
ORDER BY [Buffer Pool Rank] OPTION (RECOMPILE);
------

-- Tells you how much memory (in the buffer pool) 
-- is being used by each database on the instance



-- Get a count of SQL connections by IP address (Query 7) (Connection Counts by IP Address)    
SELECT ec.client_net_address, es.[program_name], es.[host_name], es.login_name, 
COUNT(ec.session_id) AS [connection count] 
FROM sys.dm_exec_sessions AS es WITH (NOLOCK) 
INNER JOIN sys.dm_exec_connections AS ec WITH (NOLOCK) 
ON es.session_id = ec.session_id 
GROUP BY ec.client_net_address, es.[program_name], es.[host_name], es.login_name  
ORDER BY ec.client_net_address, es.[program_name] OPTION (RECOMPILE);
------

-- This helps you figure where your database load is coming from
-- and verifies connectivity from other machines

-- Solving Connectivity errors to SQL Server
-- https://bit.ly/2EgzoD0



-- Get Average Task Counts (run multiple times)  (Query 8) (Avg Task Counts)
SELECT AVG(current_tasks_count) AS [Avg Task Count], 
AVG(work_queue_count) AS [Avg Work Queue Count],
AVG(runnable_tasks_count) AS [Avg Runnable Task Count],
AVG(pending_disk_io_count) AS [Avg Pending DiskIO Count]
FROM sys.dm_os_schedulers WITH (NOLOCK)
WHERE scheduler_id < 255 OPTION (RECOMPILE);
------

-- Sustained values above 10 suggest further investigation in that area (depending on your Service Tier)
-- Avg Task Counts will be higher with lower service tiers
-- High Avg Task Counts are often caused by blocking/deadlocking or other resource contention

-- Sustained values above 1 suggest further investigation in that area
-- High Avg Runnable Task Counts are a good sign of CPU pressure
-- High Avg Pending DiskIO Counts are a sign of disk pressure



-- Detect blocking (run multiple times)  (Query 9) (Detect Blocking)						
SELECT t1.resource_type AS [lock type], DB_NAME(resource_database_id) AS [database],
t1.resource_associated_entity_id AS [blk object],t1.request_mode AS [lock req],  -- lock requested
t1.request_session_id AS [waiter sid], t2.wait_duration_ms AS [wait time],       -- spid of waiter  
(SELECT [text] FROM sys.dm_exec_requests AS r WITH (NOLOCK)                      -- get sql for waiter
CROSS APPLY sys.dm_exec_sql_text(r.[sql_handle]) 
WHERE r.session_id = t1.request_session_id) AS [waiter_batch],
(SELECT SUBSTRING(qt.[text],r.statement_start_offset/2, 
    (CASE WHEN r.statement_end_offset = -1 
    THEN LEN(CONVERT(nvarchar(max), qt.[text])) * 2 
    ELSE r.statement_end_offset END - r.statement_start_offset)/2) 
FROM sys.dm_exec_requests AS r WITH (NOLOCK)
CROSS APPLY sys.dm_exec_sql_text(r.[sql_handle]) AS qt
WHERE r.session_id = t1.request_session_id) AS [waiter_stmt],					-- statement blocked
t2.blocking_session_id AS [blocker sid],										-- spid of blocker
(SELECT [text] FROM sys.sysprocesses AS p										-- get sql for blocker
CROSS APPLY sys.dm_exec_sql_text(p.[sql_handle]) 
WHERE p.spid = t2.blocking_session_id) AS [blocker_batch]
FROM sys.dm_tran_locks AS t1 WITH (NOLOCK)
INNER JOIN sys.dm_os_waiting_tasks AS t2 WITH (NOLOCK)
ON t1.lock_owner_address = t2.resource_address OPTION (RECOMPILE);
------

-- Helps troubleshoot blocking and deadlocking issues
-- The results will change from second to second on a busy system
-- You should run this query multiple times when you see signs of blocking



-- Page Life Expectancy (PLE) value for each NUMA node in current instance  (Query 10) (PLE by NUMA Node)
SELECT @@SERVERNAME AS [Server Name], RTRIM([object_name]) AS [Object Name], 
       instance_name, cntr_value AS [Page Life Expectancy]
FROM sys.dm_os_performance_counters WITH (NOLOCK)
WHERE [object_name] LIKE N'%Buffer Node%' -- Handles named instances
AND counter_name = N'Page life expectancy' OPTION (RECOMPILE);
------

-- PLE is a good measurement of internal memory pressure
-- Higher PLE is better. Watch the trend over time, not the absolute value
-- This will only return one row for non-NUMA systems

-- Page Life Expectancy isn’t what you think…
-- https://bit.ly/2EgynLa


-- Memory Grants Pending value for current instance  (Query 11) (Memory Grants Pending)
SELECT @@SERVERNAME AS [Server Name], RTRIM([object_name]) AS [Object Name], cntr_value AS [Memory Grants Pending]                                                                                                       
FROM sys.dm_os_performance_counters WITH (NOLOCK)
WHERE [object_name] LIKE N'%Memory Manager%' -- Handles named instances
AND counter_name = N'Memory Grants Pending' OPTION (RECOMPILE);
------

-- Run multiple times, and run periodically if you suspect you are under memory pressure
-- Memory Grants Pending above zero for a sustained period is a very strong indicator of internal memory pressure


-- Memory Clerk Usage for instance  (Query 12) (Memory Clerk Usage)
-- Look for high value for CACHESTORE_SQLCP (Ad-hoc query plans)
SELECT TOP(10) mc.[type] AS [Memory Clerk Type], 
       CAST((SUM(mc.pages_kb)/1024.0) AS DECIMAL (15,2)) AS [Memory Usage (MB)] 
FROM sys.dm_os_memory_clerks AS mc WITH (NOLOCK)
GROUP BY mc.[type]  
ORDER BY SUM(mc.pages_kb) DESC OPTION (RECOMPILE);
------

-- MEMORYCLERK_SQLBUFFERPOOL was new for SQL Server 2012. It should be your highest consumer of memory

-- CACHESTORE_SQLCP  SQL Plans         
-- These are cached SQL statements or batches that aren't in stored procedures, functions and triggers
-- Watch out for high values for CACHESTORE_SQLCP
-- Enabling 'optimize for ad hoc workloads' at the instance level can help reduce this


-- CACHESTORE_OBJCP  Object Plans      
-- These are compiled plans for stored procedures, functions and triggers



-- Find single-use, ad-hoc and prepared queries that are bloating the plan cache  (Query 13) (Ad hoc Queries)   
SELECT TOP(50) DB_NAME(t.[dbid]) AS [Database Name], t.[text] AS [Query Text], 
cp.objtype AS [Object Type], cp.cacheobjtype AS [Cache Object Type],  
cp.size_in_bytes/1024 AS [Plan Size in KB]
FROM sys.dm_exec_cached_plans AS cp WITH (NOLOCK)
CROSS APPLY sys.dm_exec_sql_text(plan_handle) AS t
WHERE cp.cacheobjtype = N'Compiled Plan' 
AND cp.objtype IN (N'Adhoc', N'Prepared') 
AND cp.usecounts = 1
ORDER BY cp.size_in_bytes DESC, DB_NAME(t.[dbid]) OPTION (RECOMPILE);
------

-- Gives you the text, type and size of single-use ad-hoc and prepared queries that waste space in the plan cache
-- Enabling forced parameterization for the database can help, but test first!

-- Plan cache, adhoc workloads and clearing the single-use plan cache bloat
-- https://bit.ly/2EfYOkl






-- Database specific queries *****************************************************************


-- Azure SQL Database size  (Query 14) (Azure SQL DB Size)
SELECT CAST(SUM(CAST(FILEPROPERTY(name, 'SpaceUsed') AS bigint) * 8192.) / 1024 / 1024 AS DECIMAL(15,2)) AS [Database Size In MB],
       CAST(SUM(CAST(FILEPROPERTY(name, 'SpaceUsed') AS bigint) * 8192.) / 1024 / 1024 / 1024 AS DECIMAL(15,2)) AS [Database Size In GB]
FROM sys.database_files WITH (NOLOCK)
WHERE [type_desc] = N'ROWS' OPTION (RECOMPILE);
------

-- This gives you the actual space usage within the data file only, to match what the Azure portal shows for the database size

-- Determining Database Size in Azure SQL Database V12
-- https://bit.ly/2JjrqNh



-- Individual File Sizes and space available for current database  (Query 15) (File Sizes and Space)
SELECT f.name AS [File Name] , f.physical_name AS [Physical Name], 
CAST((f.size/128.0) AS DECIMAL(15,2)) AS [Total Size in MB],
CAST(f.size/128.0 - CAST(FILEPROPERTY(f.name, 'SpaceUsed') AS int)/128.0 AS DECIMAL(15,2)) 
AS [Available Space In MB], f.[file_id], fg.name AS [Filegroup Name],
f.is_percent_growth, f.growth, fg.is_default, fg.is_read_only, 
fg.is_autogrow_all_files
FROM sys.database_files AS f WITH (NOLOCK) 
LEFT OUTER JOIN sys.filegroups AS fg WITH (NOLOCK)
ON f.data_space_id = fg.data_space_id
ORDER BY f.[file_id] OPTION (RECOMPILE);
------

-- Look at how large and how full the files are and where they are located

-- is_autogrow_all_files was new for SQL Server 2016. Equivalent to TF 1117 for user databases

-- SQL Server 2016: Changes in default behavior for autogrow and allocations for tempdb and user databases
-- http://bit.ly/2evRZSR



-- Log space usage for current database  (Query 16) (Log Space Usage)
SELECT DB_NAME(lsu.database_id) AS [Database Name], db.recovery_model_desc AS [Recovery Model],
		CAST(lsu.total_log_size_in_bytes/1048576.0 AS DECIMAL(10, 2)) AS [Total Log Space (MB)],
		CAST(lsu.used_log_space_in_bytes/1048576.0 AS DECIMAL(10, 2)) AS [Used Log Space (MB)], 
		CAST(lsu.used_log_space_in_percent AS DECIMAL(10, 2)) AS [Used Log Space %],
		CAST(lsu.log_space_in_bytes_since_last_backup/1048576.0 AS DECIMAL(10, 2)) AS [Used Log Space Since Last Backup (MB)],
		db.log_reuse_wait_desc		 
FROM sys.dm_db_log_space_usage AS lsu WITH (NOLOCK)
INNER JOIN sys.databases AS db WITH (NOLOCK)
ON lsu.database_id = db.database_id
OPTION (RECOMPILE);
------

-- Look at log file size and usage, along with the log reuse wait description for the current database


-- Get VLF Count for current database (Query 17) (VLF Counts)
SELECT [name] AS [Database Name], [VLF Count]
FROM sys.databases AS db WITH (NOLOCK)
CROSS APPLY (SELECT file_id, COUNT(*) AS [VLF Count]
		     FROM sys.dm_db_log_info(db.database_id)
			 GROUP BY file_id) AS li
WHERE [name] <> N'master'
ORDER BY [VLF Count] DESC OPTION (RECOMPILE);
------

-- High VLF counts can affect write performance to the log file
-- and they can make full database restores and crash recovery take much longer
-- Try to keep your VLF counts under 200 in most cases (depending on log file size)

-- Important change to VLF creation algorithm in SQL Server 2014
-- https://bit.ly/2Hsjbg4



-- Status of last VLF for current database  (Query 18) (Last VLF Status)
SELECT TOP(1) DB_NAME(li.database_id) AS [Database Name], li.[file_id],
               li.vlf_size_mb, li.vlf_sequence_number, li.vlf_active, li.vlf_status
FROM sys.dm_db_log_info(DB_ID()) AS li 
ORDER BY vlf_sequence_number DESC OPTION (RECOMPILE);
------

-- Determine whether you will be able to shrink the transaction log file

-- vlf_status Values
-- 0 is inactive 
-- 1 is initialized but unused 
-- 2 is active


-- Important database properties for current database   (Query 19) (Database Properties)
SELECT db.[name] AS [Database Name], db.recovery_model_desc AS [Recovery Model], 
db.state_desc, db.containment_desc, db.log_reuse_wait_desc AS [Log Reuse Wait Description], 
db.[compatibility_level] AS [DB Compatibility Level], 
db.is_mixed_page_allocation_on, db.page_verify_option_desc AS [Page Verify Option], 
db.is_auto_create_stats_on, db.is_auto_update_stats_on, db.is_auto_update_stats_async_on, db.is_parameterization_forced, 
db.snapshot_isolation_state_desc, db.is_read_committed_snapshot_on, db.is_auto_close_on, db.is_auto_shrink_on, 
db.target_recovery_time_in_seconds, db.is_cdc_enabled, db.is_memory_optimized_elevate_to_snapshot_on, 
db.delayed_durability_desc, db.is_auto_create_stats_incremental_on,
db.is_query_store_on, db.is_sync_with_backup, db.is_temporal_history_retention_enabled,
db.is_encrypted, is_result_set_caching_on, is_accelerated_database_recovery_on, is_tempdb_spill_to_remote_store  
FROM sys.databases AS db WITH (NOLOCK)
WHERE db.[name] <> N'master'
ORDER BY db.[name] OPTION (RECOMPILE);
------

-- Things to look at:
-- What recovery model are you using?
-- What is the log reuse wait description?
-- What compatibility level is the database on? 
-- What is the Page Verify Option? (should be CHECKSUM)
-- Is Auto Update Statistics Asynchronously enabled?
-- Is Delayed Durability enabled?




-- Get database scoped configuration values for current database (Query 20) (Database-scoped Configurations)
SELECT configuration_id, [name], [value] AS [value_for_primary]
FROM sys.database_scoped_configurations WITH (NOLOCK) OPTION (RECOMPILE);
------

-- This lets you see the value of these new properties for the current database

-- Clear plan cache for current database
-- ALTER DATABASE SCOPED CONFIGURATION CLEAR PROCEDURE_CACHE;

-- ALTER DATABASE SCOPED CONFIGURATION (Transact-SQL)
-- https://bit.ly/2sOH7nb


-- I/O Statistics by file for the current database  (Query 21) (IO Stats By File)
SELECT DB_NAME(DB_ID()) AS [Database Name], df.name AS [Logical Name], vfs.[file_id], df.type_desc,
df.physical_name AS [Physical Name], CAST(vfs.size_on_disk_bytes/1048576.0 AS DECIMAL(10, 2)) AS [Size on Disk (MB)],
vfs.num_of_reads, vfs.num_of_writes, vfs.io_stall_read_ms, vfs.io_stall_write_ms,
CAST(100. * vfs.io_stall_read_ms/(vfs.io_stall_read_ms + vfs.io_stall_write_ms) AS DECIMAL(10,1)) AS [IO Stall Reads Pct],
CAST(100. * vfs.io_stall_write_ms/(vfs.io_stall_write_ms + vfs.io_stall_read_ms) AS DECIMAL(10,1)) AS [IO Stall Writes Pct],
(vfs.num_of_reads + vfs.num_of_writes) AS [Writes + Reads], 
CAST(vfs.num_of_bytes_read/1048576.0 AS DECIMAL(10, 2)) AS [MB Read], 
CAST(vfs.num_of_bytes_written/1048576.0 AS DECIMAL(10, 2)) AS [MB Written],
CAST(100. * vfs.num_of_reads/(vfs.num_of_reads + vfs.num_of_writes) AS DECIMAL(10,1)) AS [# Reads Pct],
CAST(100. * vfs.num_of_writes/(vfs.num_of_reads + vfs.num_of_writes) AS DECIMAL(10,1)) AS [# Write Pct],
CAST(100. * vfs.num_of_bytes_read/(vfs.num_of_bytes_read + vfs.num_of_bytes_written) AS DECIMAL(10,1)) AS [Read Bytes Pct],
CAST(100. * vfs.num_of_bytes_written/(vfs.num_of_bytes_read + vfs.num_of_bytes_written) AS DECIMAL(10,1)) AS [Written Bytes Pct]
FROM sys.dm_io_virtual_file_stats(DB_ID(), NULL) AS vfs
INNER JOIN sys.database_files AS df WITH (NOLOCK)
ON vfs.[file_id]= df.[file_id] OPTION (RECOMPILE);
------

-- This helps you characterize your workload better from an I/O perspective for this database
-- It helps you determine whether you has an OLTP or DW/DSS type of workload


-- Get recent resource usage (Query 22) (Recent Resource Usage)
SELECT end_time, dtu_limit, cpu_limit, avg_cpu_percent, avg_memory_usage_percent, 
       avg_data_io_percent, avg_log_write_percent,  xtp_storage_percent,
       max_worker_percent, max_session_percent,  avg_login_rate_percent,  
	   avg_instance_cpu_percent, avg_instance_memory_percent
FROM sys.dm_db_resource_stats WITH (NOLOCK) 
ORDER BY end_time DESC OPTION (RECOMPILE);
------

-- Returns a row of usage metrics every 15 seconds, going back 64 minutes
-- The end_time column is UTC time

-- sys.dm_db_resource_stats (Azure SQL Database)
-- https://bit.ly/2HaSpKn



-- Get recent resource usage (Query 23) (Avg/Max Resource Usage)
SELECT CAST(AVG(avg_cpu_percent) AS DECIMAL(10,2)) AS [Average CPU Utilization In Percent],   
       CAST(MAX(avg_cpu_percent) AS DECIMAL(10,2)) AS [Maximum CPU Utilization In Percent],   
       CAST(AVG(avg_data_io_percent) AS DECIMAL(10,2)) AS [Average Data IO In Percent],   
       CAST(MAX(avg_data_io_percent) AS DECIMAL(10,2)) AS [Maximum Data IO In Percent],   
       CAST(AVG(avg_log_write_percent) AS DECIMAL(10,2)) AS [Average Log Write Utilization In Percent],   
       CAST(MAX(avg_log_write_percent) AS DECIMAL(10,2)) AS [Maximum Log Write Utilization In Percent],   
       CAST(AVG(avg_memory_usage_percent) AS DECIMAL(10,2)) AS [Average Memory Usage In Percent],   
       CAST(MAX(avg_memory_usage_percent) AS DECIMAL(10,2)) AS [Maximum Memory Usage In Percent]   
FROM sys.dm_db_resource_stats WITH (NOLOCK) OPTION (RECOMPILE); 
------


-- Isolate top waits for this database since last restart or failover (Query 24) (Top DB Waits)
WITH [Waits] 
AS (SELECT wait_type, wait_time_ms/ 1000.0 AS [WaitS],
          (wait_time_ms - signal_wait_time_ms) / 1000.0 AS [ResourceS],
           signal_wait_time_ms / 1000.0 AS [SignalS],
           waiting_tasks_count AS [WaitCount],
           100.0 *  wait_time_ms / SUM (wait_time_ms) OVER() AS [Percentage],
           ROW_NUMBER() OVER(ORDER BY wait_time_ms DESC) AS [RowNum]
    FROM sys.dm_db_wait_stats WITH (NOLOCK)
    WHERE [wait_type] NOT IN (
        N'BROKER_EVENTHANDLER', N'BROKER_RECEIVE_WAITFOR', N'BROKER_TASK_STOP',
		N'BROKER_TO_FLUSH', N'BROKER_TRANSMITTER', N'CHECKPOINT_QUEUE',
        N'CHKPT', N'CLR_AUTO_EVENT', N'CLR_MANUAL_EVENT', N'CLR_SEMAPHORE',
        N'DBMIRROR_DBM_EVENT', N'DBMIRROR_EVENTS_QUEUE', N'DBMIRROR_WORKER_QUEUE',
		N'DBMIRRORING_CMD', N'DIRTY_PAGE_POLL', N'DISPATCHER_QUEUE_SEMAPHORE',
        N'EXECSYNC', N'FSAGENT', N'FT_IFTS_SCHEDULER_IDLE_WAIT', N'FT_IFTSHC_MUTEX',
        N'HADR_CLUSAPI_CALL', N'HADR_FILESTREAM_IOMGR_IOCOMPLETION', N'HADR_LOGCAPTURE_WAIT', 
		N'HADR_NOTIFICATION_DEQUEUE', N'HADR_TIMER_TASK', N'HADR_WORK_QUEUE',
        N'KSOURCE_WAKEUP', N'LAZYWRITER_SLEEP', N'LOGMGR_QUEUE', 
		N'MEMORY_ALLOCATION_EXT', N'ONDEMAND_TASK_QUEUE',
		N'PREEMPTIVE_HADR_LEASE_MECHANISM', N'PREEMPTIVE_SP_SERVER_DIAGNOSTICS',
		N'PREEMPTIVE_ODBCOPS',
		N'PREEMPTIVE_OS_LIBRARYOPS', N'PREEMPTIVE_OS_COMOPS', N'PREEMPTIVE_OS_CRYPTOPS',
		N'PREEMPTIVE_OS_PIPEOPS', N'PREEMPTIVE_OS_AUTHENTICATIONOPS',
		N'PREEMPTIVE_OS_GENERICOPS', N'PREEMPTIVE_OS_VERIFYTRUST',
		N'PREEMPTIVE_OS_FILEOPS', N'PREEMPTIVE_OS_DEVICEOPS', N'PREEMPTIVE_OS_QUERYREGISTRY',
		N'PREEMPTIVE_OS_WRITEFILE',
		N'PREEMPTIVE_XE_CALLBACKEXECUTE', N'PREEMPTIVE_XE_DISPATCHER',
		N'PREEMPTIVE_XE_GETTARGETSTATE', N'PREEMPTIVE_XE_SESSIONCOMMIT',
		N'PREEMPTIVE_XE_TARGETINIT', N'PREEMPTIVE_XE_TARGETFINALIZE',
		N'PREEMPTIVE_XHTTP',
        N'PWAIT_ALL_COMPONENTS_INITIALIZED', N'PWAIT_DIRECTLOGCONSUMER_GETNEXT',
		N'QDS_PERSIST_TASK_MAIN_LOOP_SLEEP',
		N'QDS_ASYNC_QUEUE',
        N'QDS_CLEANUP_STALE_QUERIES_TASK_MAIN_LOOP_SLEEP', N'REQUEST_FOR_DEADLOCK_SEARCH',
		N'RESOURCE_GOVERNOR_IDLE',
		N'RESOURCE_QUEUE', N'SERVER_IDLE_CHECK', N'SLEEP_BPOOL_FLUSH', N'SLEEP_DBSTARTUP',
		N'SLEEP_DCOMSTARTUP', N'SLEEP_MASTERDBREADY', N'SLEEP_MASTERMDREADY',
        N'SLEEP_MASTERUPGRADED', N'SLEEP_MSDBSTARTUP', N'SLEEP_SYSTEMTASK', N'SLEEP_TASK',
        N'SLEEP_TEMPDBSTARTUP', N'SNI_HTTP_ACCEPT', N'SP_SERVER_DIAGNOSTICS_SLEEP',
		N'SQLTRACE_BUFFER_FLUSH', N'SQLTRACE_INCREMENTAL_FLUSH_SLEEP', N'SQLTRACE_WAIT_ENTRIES',
		N'WAIT_FOR_RESULTS', N'WAITFOR', N'WAITFOR_TASKSHUTDOWN', N'WAIT_XTP_HOST_WAIT',
		N'WAIT_XTP_OFFLINE_CKPT_NEW_LOG', N'WAIT_XTP_CKPT_CLOSE', N'WAIT_XTP_RECOVERY',
		N'XE_BUFFERMGR_ALLPROCESSED_EVENT', N'XE_DISPATCHER_JOIN',
        N'XE_DISPATCHER_WAIT', N'XE_LIVE_TARGET_TVF', N'XE_TIMER_EVENT')
    AND waiting_tasks_count > 0)
SELECT
    MAX (W1.wait_type) AS [WaitType],
	CAST (MAX (W1.Percentage) AS DECIMAL (5,2)) AS [Wait Percentage],
	CAST ((MAX (W1.WaitS) / MAX (W1.WaitCount)) AS DECIMAL (16,4)) AS [AvgWait_Sec],
    CAST ((MAX (W1.ResourceS) / MAX (W1.WaitCount)) AS DECIMAL (16,4)) AS [AvgRes_Sec],
    CAST ((MAX (W1.SignalS) / MAX (W1.WaitCount)) AS DECIMAL (16,4)) AS [AvgSig_Sec],
    CAST (MAX (W1.WaitS) AS DECIMAL (16,2)) AS [Total_Wait_Sec],
    CAST (MAX (W1.ResourceS) AS DECIMAL (16,2)) AS [Resource_Sec],
    CAST (MAX (W1.SignalS) AS DECIMAL (16,2)) AS [Signal_Sec],
    MAX (W1.WaitCount) AS [Wait Count]   
FROM Waits AS W1
INNER JOIN Waits AS W2
ON W2.RowNum <= W1.RowNum
GROUP BY W1.RowNum
HAVING SUM (W2.Percentage) - MAX (W1.Percentage) < 99 -- percentage threshold
OPTION (RECOMPILE);
------

-- Cumulative wait stats are not as useful on an idle instance that is not under load or performance pressure

-- SQL Server Wait Types Library
-- https://bit.ly/2ePzYO2

-- The SQL Server Wait Type Repository
-- https://bit.ly/1afzfjC

-- Wait statistics, or please tell me where it hurts
-- https://bit.ly/2wsQHQE

-- SQL Server 2005 Performance Tuning using the Waits and Queues
-- https://bit.ly/1o2NFoF

-- sys.dm_db_wait_stats (Azure SQL Database)
-- https://bit.ly/2HoJOoT



-- Get most frequently executed queries for this database (Query 25) (Query Execution Counts)
SELECT TOP(50) LEFT(t.[text], 50) AS [Short Query Text], qs.execution_count AS [Execution Count],
qs.total_logical_reads AS [Total Logical Reads],
qs.total_logical_reads/qs.execution_count AS [Avg Logical Reads],
qs.total_worker_time AS [Total Worker Time],
qs.total_worker_time/qs.execution_count AS [Avg Worker Time], 
qs.total_elapsed_time AS [Total Elapsed Time],
qs.total_elapsed_time/qs.execution_count AS [Avg Elapsed Time],
CASE WHEN CONVERT(nvarchar(max), qp.query_plan) LIKE N'%<MissingIndexes>%' THEN 1 ELSE 0 END AS [Has Missing Index], 
qs.creation_time AS [Creation Time]
--,t.[text] AS [Complete Query Text], qp.query_plan AS [Query Plan] -- uncomment out these columns if not copying results to Excel
FROM sys.dm_exec_query_stats AS qs WITH (NOLOCK)
CROSS APPLY sys.dm_exec_sql_text(plan_handle) AS t 
CROSS APPLY sys.dm_exec_query_plan(plan_handle) AS qp 
WHERE t.dbid = DB_ID()
ORDER BY qs.execution_count DESC OPTION (RECOMPILE);
------


-- Get top total worker time queries for this database (Query 26) (Top Worker Time Queries)		
SELECT TOP(50) DB_NAME(t.[dbid]) AS [Database Name], 
REPLACE(REPLACE(LEFT(t.[text], 50), CHAR(10),''), CHAR(13),'') AS [Short Query Text],  
qs.total_worker_time AS [Total Worker Time], qs.min_worker_time AS [Min Worker Time],
qs.total_worker_time/qs.execution_count AS [Avg Worker Time], 
qs.max_worker_time AS [Max Worker Time], 
qs.min_elapsed_time AS [Min Elapsed Time], 
qs.total_elapsed_time/qs.execution_count AS [Avg Elapsed Time], 
qs.max_elapsed_time AS [Max Elapsed Time],
qs.min_logical_reads AS [Min Logical Reads],
qs.total_logical_reads/qs.execution_count AS [Avg Logical Reads],
qs.max_logical_reads AS [Max Logical Reads], 
qs.execution_count AS [Execution Count],
CASE WHEN CONVERT(nvarchar(max), qp.query_plan) LIKE N'%<MissingIndexes>%' THEN 1 ELSE 0 END AS [Has Missing Index],  
qs.creation_time AS [Creation Time]
--,t.[text] AS [Query Text], qp.query_plan AS [Query Plan] -- uncomment out these columns if not copying results to Excel
FROM sys.dm_exec_query_stats AS qs WITH (NOLOCK)
CROSS APPLY sys.dm_exec_sql_text(plan_handle) AS t 
CROSS APPLY sys.dm_exec_query_plan(plan_handle) AS qp
WHERE t.dbid = DB_ID() 
ORDER BY qs.total_worker_time DESC OPTION (RECOMPILE);
------

-- Helps you find the most expensive queries from a CPU perspective for this database
-- Can also help track down parameter sniffing issues


-- Get top total logical reads queries for this database (Query 27) (Top Logical Reads Queries)    
SELECT TOP(50) DB_NAME(t.[dbid]) AS [Database Name],
REPLACE(REPLACE(LEFT(t.[text], 50), CHAR(10),''), CHAR(13),'') AS [Short Query Text], 
qs.total_logical_reads AS [Total Logical Reads],
qs.min_logical_reads AS [Min Logical Reads],
qs.total_logical_reads/qs.execution_count AS [Avg Logical Reads],
qs.max_logical_reads AS [Max Logical Reads],   
qs.min_worker_time AS [Min Worker Time],
qs.total_worker_time/qs.execution_count AS [Avg Worker Time], 
qs.max_worker_time AS [Max Worker Time], 
qs.min_elapsed_time AS [Min Elapsed Time], 
qs.total_elapsed_time/qs.execution_count AS [Avg Elapsed Time], 
qs.max_elapsed_time AS [Max Elapsed Time],
qs.execution_count AS [Execution Count],
CASE WHEN CONVERT(nvarchar(max), qp.query_plan) LIKE N'%<MissingIndexes>%' THEN 1 ELSE 0 END AS [Has Missing Index],   
qs.creation_time AS [Creation Time]
--,t.[text] AS [Complete Query Text], qp.query_plan AS [Query Plan] -- uncomment out these columns if not copying results to Excel
FROM sys.dm_exec_query_stats AS qs WITH (NOLOCK)
CROSS APPLY sys.dm_exec_sql_text(plan_handle) AS t 
CROSS APPLY sys.dm_exec_query_plan(plan_handle) AS qp
WHERE t.dbid = DB_ID()  
ORDER BY qs.total_logical_reads DESC OPTION (RECOMPILE);
------


-- Helps you find the most expensive queries from a memory perspective for this database
-- Can also help track down parameter sniffing issues



-- Get top average elapsed time queries for this database (Query 28) (Top Avg Elapsed Time Queries)   
SELECT TOP(50) DB_NAME(t.[dbid]) AS [Database Name], 
REPLACE(REPLACE(LEFT(t.[text], 255), CHAR(10),''), CHAR(13),'') AS [Short Query Text],  
qs.total_elapsed_time/qs.execution_count AS [Avg Elapsed Time],
qs.min_elapsed_time, qs.max_elapsed_time, qs.last_elapsed_time,
qs.execution_count AS [Execution Count],  
qs.total_logical_reads/qs.execution_count AS [Avg Logical Reads], 
qs.total_physical_reads/qs.execution_count AS [Avg Physical Reads], 
qs.total_worker_time/qs.execution_count AS [Avg Worker Time],
CASE WHEN CONVERT(nvarchar(max), qp.query_plan) LIKE N'%<MissingIndexes>%' THEN 1 ELSE 0 END AS [Has Missing Index],  
qs.creation_time AS [Creation Time]
, qp.query_plan AS [Query Plan] -- comment out this column if copying results to Excel
FROM sys.dm_exec_query_stats AS qs WITH (NOLOCK)
CROSS APPLY sys.dm_exec_sql_text(plan_handle) AS t 
CROSS APPLY sys.dm_exec_query_plan(plan_handle) AS qp
WHERE t.dbid = DB_ID()  
ORDER BY qs.total_elapsed_time/qs.execution_count DESC OPTION (RECOMPILE);
------

-- Helps you find the highest average elapsed time queries for this database
-- Can also help track down parameter sniffing issues



-- Top Cached SPs By Execution Count (Query 29) (SP Execution Counts)
SELECT TOP(100) p.name AS [SP Name], qs.execution_count AS [Execution Count],
ISNULL(qs.execution_count/DATEDIFF(Minute, qs.cached_time, GETDATE()), 0) AS [Calls/Minute],
qs.total_elapsed_time/qs.execution_count AS [Avg Elapsed Time],
qs.total_worker_time/qs.execution_count AS [Avg Worker Time],    
qs.total_logical_reads/qs.execution_count AS [Avg Logical Reads],
CASE WHEN CONVERT(nvarchar(max), qp.query_plan) LIKE N'%<MissingIndexes>%' THEN 1 ELSE 0 END AS [Has Missing Index],
FORMAT(qs.last_execution_time, 'yyyy-MM-dd HH:mm:ss', 'en-US') AS [Last Execution Time], 
FORMAT(qs.cached_time, 'yyyy-MM-dd HH:mm:ss', 'en-US') AS [Plan Cached Time]
-- ,qp.query_plan AS [Query Plan] -- Uncomment if you want the Query Plan
FROM sys.procedures AS p WITH (NOLOCK)
INNER JOIN sys.dm_exec_procedure_stats AS qs WITH (NOLOCK)
ON p.[object_id] = qs.[object_id]
CROSS APPLY sys.dm_exec_query_plan(qs.plan_handle) AS qp
WHERE qs.database_id = DB_ID()
AND DATEDIFF(Minute, qs.cached_time, GETDATE()) > 0
ORDER BY qs.execution_count DESC OPTION (RECOMPILE);
------

-- Tells you which cached stored procedures are called the most often
-- This helps you characterize and baseline your workload


-- Top Cached SPs By Avg Elapsed Time (Query 30) (SP Avg Elapsed Time)
SELECT TOP(25) p.name AS [SP Name], qs.min_elapsed_time, qs.total_elapsed_time/qs.execution_count AS [avg_elapsed_time], 
qs.max_elapsed_time, qs.last_elapsed_time, qs.total_elapsed_time, qs.execution_count, 
ISNULL(qs.execution_count/DATEDIFF(Minute, qs.cached_time, GETDATE()), 0) AS [Calls/Minute], 
qs.total_worker_time/qs.execution_count AS [AvgWorkerTime], 
qs.total_worker_time AS [TotalWorkerTime],
CASE WHEN CONVERT(nvarchar(max), qp.query_plan) LIKE N'%<MissingIndexes>%' THEN 1 ELSE 0 END AS [Has Missing Index],
FORMAT(qs.last_execution_time, 'yyyy-MM-dd HH:mm:ss', 'en-US') AS [Last Execution Time], 
FORMAT(qs.cached_time, 'yyyy-MM-dd HH:mm:ss', 'en-US') AS [Plan Cached Time]
-- ,qp.query_plan AS [Query Plan] -- Uncomment if you want the Query Plan
FROM sys.procedures AS p WITH (NOLOCK)
INNER JOIN sys.dm_exec_procedure_stats AS qs WITH (NOLOCK)
ON p.[object_id] = qs.[object_id]
CROSS APPLY sys.dm_exec_query_plan(qs.plan_handle) AS qp
WHERE qs.database_id = DB_ID()
AND DATEDIFF(Minute, qs.cached_time, GETDATE()) > 0
ORDER BY avg_elapsed_time DESC OPTION (RECOMPILE);
------

-- This helps you find high average elapsed time cached stored procedures that
-- may be easy to optimize with standard query tuning techniques



-- Top Cached SPs By Total Worker time. Worker time relates to CPU cost  (Query 31) (SP Worker Time)
SELECT TOP(25) p.name AS [SP Name], qs.total_worker_time AS [TotalWorkerTime], 
qs.total_worker_time/qs.execution_count AS [AvgWorkerTime], qs.execution_count, 
ISNULL(qs.execution_count/DATEDIFF(Minute, qs.cached_time, GETDATE()), 0) AS [Calls/Minute],
qs.total_elapsed_time, qs.total_elapsed_time/qs.execution_count AS [avg_elapsed_time],
CASE WHEN CONVERT(nvarchar(max), qp.query_plan) LIKE N'%<MissingIndexes>%' THEN 1 ELSE 0 END AS [Has Missing Index],
FORMAT(qs.last_execution_time, 'yyyy-MM-dd HH:mm:ss', 'en-US') AS [Last Execution Time], 
FORMAT(qs.cached_time, 'yyyy-MM-dd HH:mm:ss', 'en-US') AS [Plan Cached Time]
-- ,qp.query_plan AS [Query Plan] -- Uncomment if you want the Query Plan
FROM sys.procedures AS p WITH (NOLOCK)
INNER JOIN sys.dm_exec_procedure_stats AS qs WITH (NOLOCK)
ON p.[object_id] = qs.[object_id]
CROSS APPLY sys.dm_exec_query_plan(qs.plan_handle) AS qp
WHERE qs.database_id = DB_ID()
AND DATEDIFF(Minute, qs.cached_time, GETDATE()) > 0
ORDER BY qs.total_worker_time DESC OPTION (RECOMPILE);
------

-- This helps you find the most expensive cached stored procedures from a CPU perspective
-- You should look at this if you see signs of CPU pressure


-- Top Cached SPs By Total Logical Reads. Logical reads relate to memory pressure  (Query 32) (SP Logical Reads)
SELECT TOP(25) p.name AS [SP Name], qs.total_logical_reads AS [TotalLogicalReads], 
qs.total_logical_reads/qs.execution_count AS [AvgLogicalReads],qs.execution_count, 
ISNULL(qs.execution_count/DATEDIFF(Minute, qs.cached_time, GETDATE()), 0) AS [Calls/Minute], 
qs.total_elapsed_time, qs.total_elapsed_time/qs.execution_count AS [avg_elapsed_time],
CASE WHEN CONVERT(nvarchar(max), qp.query_plan) LIKE N'%<MissingIndexes>%' THEN 1 ELSE 0 END AS [Has Missing Index], 
FORMAT(qs.last_execution_time, 'yyyy-MM-dd HH:mm:ss', 'en-US') AS [Last Execution Time], 
FORMAT(qs.cached_time, 'yyyy-MM-dd HH:mm:ss', 'en-US') AS [Plan Cached Time]
-- ,qp.query_plan AS [Query Plan] -- Uncomment if you want the Query Plan
FROM sys.procedures AS p WITH (NOLOCK)
INNER JOIN sys.dm_exec_procedure_stats AS qs WITH (NOLOCK)
ON p.[object_id] = qs.[object_id]
CROSS APPLY sys.dm_exec_query_plan(qs.plan_handle) AS qp
WHERE qs.database_id = DB_ID()
AND DATEDIFF(Minute, qs.cached_time, GETDATE()) > 0
ORDER BY qs.total_logical_reads DESC OPTION (RECOMPILE);
------

-- This helps you find the most expensive cached stored procedures from a memory perspective
-- You should look at this if you see signs of memory pressure


-- Top Cached SPs By Total Physical Reads. Physical reads relate to disk read I/O pressure  (Query 33) (SP Physical Reads)
SELECT TOP(25) p.name AS [SP Name],qs.total_physical_reads AS [TotalPhysicalReads], 
qs.total_physical_reads/qs.execution_count AS [AvgPhysicalReads], qs.execution_count, 
qs.total_logical_reads,qs.total_elapsed_time, qs.total_elapsed_time/qs.execution_count AS [avg_elapsed_time],
CASE WHEN CONVERT(nvarchar(max), qp.query_plan) LIKE N'%<MissingIndexes>%' THEN 1 ELSE 0 END AS [Has Missing Index],
FORMAT(qs.last_execution_time, 'yyyy-MM-dd HH:mm:ss', 'en-US') AS [Last Execution Time], 
FORMAT(qs.cached_time, 'yyyy-MM-dd HH:mm:ss', 'en-US') AS [Plan Cached Time]
-- ,qp.query_plan AS [Query Plan] -- Uncomment if you want the Query Plan 
FROM sys.procedures AS p WITH (NOLOCK)
INNER JOIN sys.dm_exec_procedure_stats AS qs WITH (NOLOCK)
ON p.[object_id] = qs.[object_id]
CROSS APPLY sys.dm_exec_query_plan(qs.plan_handle) AS qp
WHERE qs.database_id = DB_ID()
AND qs.total_physical_reads > 0
ORDER BY qs.total_physical_reads DESC, qs.total_logical_reads DESC OPTION (RECOMPILE);
------

-- This helps you find the most expensive cached stored procedures from a read I/O perspective
-- You should look at this if you see signs of I/O pressure or of memory pressure
       


-- Top Cached SPs By Total Logical Writes (Query 34) (SP Logical Writes)
-- Logical writes relate to both memory and disk I/O pressure 
SELECT TOP(25) p.name AS [SP Name], qs.total_logical_writes AS [TotalLogicalWrites], 
qs.total_logical_writes/qs.execution_count AS [AvgLogicalWrites], qs.execution_count,
ISNULL(qs.execution_count/DATEDIFF(Minute, qs.cached_time, GETDATE()), 0) AS [Calls/Minute],
qs.total_elapsed_time, qs.total_elapsed_time/qs.execution_count AS [avg_elapsed_time],
CASE WHEN CONVERT(nvarchar(max), qp.query_plan) LIKE N'%<MissingIndexes>%' THEN 1 ELSE 0 END AS [Has Missing Index], 
FORMAT(qs.last_execution_time, 'yyyy-MM-dd HH:mm:ss', 'en-US') AS [Last Execution Time], 
FORMAT(qs.cached_time, 'yyyy-MM-dd HH:mm:ss', 'en-US') AS [Plan Cached Time]
-- ,qp.query_plan AS [Query Plan] -- Uncomment if you want the Query Plan 
FROM sys.procedures AS p WITH (NOLOCK)
INNER JOIN sys.dm_exec_procedure_stats AS qs WITH (NOLOCK)
ON p.[object_id] = qs.[object_id]
CROSS APPLY sys.dm_exec_query_plan(qs.plan_handle) AS qp
WHERE qs.database_id = DB_ID()
AND qs.total_logical_writes > 0
AND DATEDIFF(Minute, qs.cached_time, GETDATE()) > 0
ORDER BY qs.total_logical_writes DESC OPTION (RECOMPILE);
------

-- This helps you find the most expensive cached stored procedures from a write I/O perspective
-- You should look at this if you see signs of I/O pressure or of memory pressure



-- Lists the top statements by average input/output usage for the current database  (Query 35) (Top IO Statements)
SELECT TOP(50) OBJECT_NAME(qt.objectid, dbid) AS [SP Name],
(qs.total_logical_reads + qs.total_logical_writes) /qs.execution_count AS [Avg IO], qs.execution_count AS [Execution Count],
SUBSTRING(qt.[text],qs.statement_start_offset/2, 
	(CASE 
		WHEN qs.statement_end_offset = -1 
	 THEN LEN(CONVERT(nvarchar(max), qt.[text])) * 2 
		ELSE qs.statement_end_offset 
	 END - qs.statement_start_offset)/2) AS [Query Text]	
FROM sys.dm_exec_query_stats AS qs WITH (NOLOCK)
CROSS APPLY sys.dm_exec_sql_text(qs.sql_handle) AS qt
WHERE qt.[dbid] = DB_ID()
ORDER BY [Avg IO] DESC OPTION (RECOMPILE);
------

-- Helps you find the most expensive statements for I/O by SP



-- Possible Bad NC Indexes (writes > reads)  (Query 36) (Bad NC Indexes)
SELECT SCHEMA_NAME(o.[schema_id]) AS [Schema Name], 
OBJECT_NAME(s.[object_id]) AS [Table Name],
i.name AS [Index Name], i.index_id, 
i.is_disabled, i.is_hypothetical, i.has_filter, i.fill_factor,
s.user_updates AS [Total Writes], s.user_seeks + s.user_scans + s.user_lookups AS [Total Reads],
s.user_updates - (s.user_seeks + s.user_scans + s.user_lookups) AS [Difference]
FROM sys.dm_db_index_usage_stats AS s WITH (NOLOCK)
INNER JOIN sys.indexes AS i WITH (NOLOCK)
ON s.[object_id] = i.[object_id]
AND i.index_id = s.index_id
INNER JOIN sys.objects AS o WITH (NOLOCK)
ON i.[object_id] = o.[object_id]
WHERE OBJECTPROPERTY(s.[object_id],'IsUserTable') = 1
AND s.database_id = DB_ID()
AND s.user_updates > (s.user_seeks + s.user_scans + s.user_lookups)
AND i.index_id > 1 AND i.[type_desc] = N'NONCLUSTERED'
AND i.is_primary_key = 0 AND i.is_unique_constraint = 0 AND i.is_unique = 0
ORDER BY [Difference] DESC, [Total Writes] DESC, [Total Reads] ASC OPTION (RECOMPILE);
------

-- Look for indexes with high numbers of writes and zero or very low numbers of reads
-- Consider your complete workload, and how long your instance has been running
-- Investigate further before dropping an index!


-- Missing Indexes for current database by Index Advantage  (Query 37) (Missing Indexes)
SELECT DISTINCT CONVERT(decimal(18,2), user_seeks * avg_total_user_cost * (avg_user_impact * 0.01)) AS [index_advantage], 
migs.last_user_seek, mid.[statement] AS [Database.Schema.Table],
mid.equality_columns, mid.inequality_columns, mid.included_columns,
migs.unique_compiles, migs.user_seeks, migs.avg_total_user_cost, migs.avg_user_impact,
OBJECT_NAME(mid.[object_id]) AS [Table Name], p.rows AS [Table Rows]
FROM sys.dm_db_missing_index_group_stats AS migs WITH (NOLOCK)
INNER JOIN sys.dm_db_missing_index_groups AS mig WITH (NOLOCK)
ON migs.group_handle = mig.index_group_handle
INNER JOIN sys.dm_db_missing_index_details AS mid WITH (NOLOCK)
ON mig.index_handle = mid.index_handle
INNER JOIN sys.partitions AS p WITH (NOLOCK)
ON p.[object_id] = mid.[object_id]
WHERE mid.database_id = DB_ID() 
ORDER BY index_advantage DESC OPTION (RECOMPILE);
------

-- Look at index advantage, last user seek time, number of user seeks to help determine source and importance
-- SQL Server is overly eager to add included columns, so beware
-- Do not just blindly add indexes that show up from this query!!!


-- Find missing index warnings for cached plans in the current database  (Query 38) (Missing Index Warnings)
-- Note: This query could take some time on a busy instance
SELECT TOP(25) OBJECT_NAME(objectid) AS [ObjectName], 
               cp.objtype, cp.usecounts, cp.size_in_bytes, query_plan
FROM sys.dm_exec_cached_plans AS cp WITH (NOLOCK)
CROSS APPLY sys.dm_exec_query_plan(cp.plan_handle) AS qp
WHERE CAST(query_plan AS NVARCHAR(MAX)) LIKE N'%MissingIndex%'
AND dbid = DB_ID()
ORDER BY cp.usecounts DESC OPTION (RECOMPILE);
------

-- Helps you connect missing indexes to specific stored procedures or queries
-- This can help you decide whether to add them or not


-- Breaks down buffers used by current database by object (table, index) in the buffer cache  (Query 39) (Buffer Usage)
-- Note: This query could take some time on a busy instance
SELECT SCHEMA_NAME(o.Schema_ID) AS [Schema Name],
OBJECT_NAME(p.[object_id]) AS [Object Name], p.index_id, 
CAST(COUNT(*)/128.0 AS DECIMAL(10, 2)) AS [Buffer size(MB)],  
COUNT(*) AS [BufferCount], p.[Rows] AS [Row Count],
p.data_compression_desc AS [Compression Type]
FROM sys.allocation_units AS a WITH (NOLOCK)
INNER JOIN sys.dm_os_buffer_descriptors AS b WITH (NOLOCK)
ON a.allocation_unit_id = b.allocation_unit_id
INNER JOIN sys.partitions AS p WITH (NOLOCK)
ON a.container_id = p.hobt_id
INNER JOIN sys.objects AS o WITH (NOLOCK)
ON p.object_id = o.object_id
WHERE b.database_id = CONVERT(int, DB_ID())
AND p.[object_id] > 100
AND OBJECT_NAME(p.[object_id]) NOT LIKE N'plan_%'
AND OBJECT_NAME(p.[object_id]) NOT LIKE N'sys%'
AND OBJECT_NAME(p.[object_id]) NOT LIKE N'xml_index_nodes%'
GROUP BY o.Schema_ID, p.[object_id], p.index_id, p.data_compression_desc, p.[Rows]
ORDER BY [BufferCount] DESC OPTION (RECOMPILE);
------

-- Tells you what tables and indexes are using the most memory in the buffer cache
-- It can help identify possible candidates for data compression


-- Get Table names, row counts, and compression status for clustered index or heap  (Query 40) (Table Sizes)
SELECT SCHEMA_NAME(o.Schema_ID) AS [Schema Name], OBJECT_NAME(p.object_id) AS [ObjectName], 
SUM(p.Rows) AS [RowCount], data_compression_desc AS [CompressionType]
FROM sys.partitions AS p WITH (NOLOCK)
INNER JOIN sys.objects AS o WITH (NOLOCK)
ON p.object_id = o.object_id
WHERE index_id < 2 --ignore the partitions from the non-clustered index if any
AND OBJECT_NAME(p.object_id) NOT LIKE N'sys%'
AND OBJECT_NAME(p.object_id) NOT LIKE N'spt_%'
AND OBJECT_NAME(p.object_id) NOT LIKE N'queue_%' 
AND OBJECT_NAME(p.object_id) NOT LIKE N'filestream_tombstone%' 
AND OBJECT_NAME(p.object_id) NOT LIKE N'fulltext%'
AND OBJECT_NAME(p.object_id) NOT LIKE N'ifts_comp_fragment%'
AND OBJECT_NAME(p.object_id) NOT LIKE N'filetable_updates%'
AND OBJECT_NAME(p.object_id) NOT LIKE N'xml_index_nodes%'
AND OBJECT_NAME(p.object_id) NOT LIKE N'sqlagent_job%'
AND OBJECT_NAME(p.object_id) NOT LIKE N'plan_persist%'
GROUP BY  SCHEMA_NAME(o.Schema_ID), p.object_id, data_compression_desc
ORDER BY SUM(p.Rows) DESC OPTION (RECOMPILE);
------

-- Gives you an idea of table sizes, and possible data compression opportunities



-- Get some key table properties (Query 41) (Table Properties)
SELECT OBJECT_NAME(t.[object_id]) AS [ObjectName], p.[rows] AS [Table Rows], p.index_id, 
       p.data_compression_desc AS [Index Data Compression],
       t.create_date, t.lock_on_bulk_load, t.lock_escalation_desc, 
	   t.is_memory_optimized, t.durability_desc, 
	   t.temporal_type_desc
FROM sys.tables AS t WITH (NOLOCK)
INNER JOIN sys.partitions AS p WITH (NOLOCK)
ON t.[object_id] = p.[object_id]
WHERE OBJECT_NAME(t.[object_id]) NOT LIKE N'sys%'
ORDER BY OBJECT_NAME(t.[object_id]), p.index_id OPTION (RECOMPILE);
------

-- Gives you some good information about your tables
-- is_memory_optimized and durability_desc were new in SQL Server 2014
-- temporal_type_desc, is_remote_data_archive_enabled, is_external are new in SQL Server 2016

-- sys.tables (Transact-SQL)
-- https://bit.ly/2Gk7998



-- When were Statistics last updated on all indexes?  (Query 42) (Statistics Update)
SELECT SCHEMA_NAME(o.Schema_ID) + N'.' + o.[NAME] AS [Object Name], o.[type_desc] AS [Object Type],
      i.[name] AS [Index Name], STATS_DATE(i.[object_id], i.index_id) AS [Statistics Date], 
      s.auto_created, s.no_recompute, s.user_created, s.is_incremental, s.is_temporary,
	  st.row_count, st.used_page_count
FROM sys.objects AS o WITH (NOLOCK)
INNER JOIN sys.indexes AS i WITH (NOLOCK)
ON o.[object_id] = i.[object_id]
INNER JOIN sys.stats AS s WITH (NOLOCK)
ON i.[object_id] = s.[object_id] 
AND i.index_id = s.stats_id
INNER JOIN sys.dm_db_partition_stats AS st WITH (NOLOCK)
ON o.[object_id] = st.[object_id]
AND i.[index_id] = st.[index_id]
WHERE o.[type] IN ('U', 'V')
AND st.row_count > 0
ORDER BY STATS_DATE(i.[object_id], i.index_id) DESC OPTION (RECOMPILE);
------  

-- Helps discover possible problems with out-of-date statistics
-- Also gives you an idea which indexes are the most active

-- sys.stats (Transact-SQL)
-- https://bit.ly/2GyAxrn



-- Look at most frequently modified indexes and statistics (Query 43) (Volatile Indexes)
SELECT o.[name] AS [Object Name], o.[object_id], o.[type_desc], s.[name] AS [Statistics Name], 
       s.stats_id, s.no_recompute, s.auto_created, s.is_incremental, s.is_temporary,
	   sp.modification_counter, sp.[rows], sp.rows_sampled, sp.last_updated
FROM sys.objects AS o WITH (NOLOCK)
INNER JOIN sys.stats AS s WITH (NOLOCK)
ON s.object_id = o.object_id
CROSS APPLY sys.dm_db_stats_properties(s.object_id, s.stats_id) AS sp
WHERE o.[type_desc] NOT IN (N'SYSTEM_TABLE', N'INTERNAL_TABLE')
AND sp.modification_counter > 0
ORDER BY sp.modification_counter DESC, o.name OPTION (RECOMPILE);
------

-- This helps you understand your workload and make better decisions about 
-- things like data compression and adding new indexes to a table



-- Get fragmentation info for all indexes above a certain size in the current database  (Query 44) (Index Fragmentation)
-- Note: This query could take some time on a very large database
SELECT DB_NAME(ps.database_id) AS [Database Name], SCHEMA_NAME(o.[schema_id]) AS [Schema Name],
OBJECT_NAME(ps.OBJECT_ID) AS [Object Name], i.[name] AS [Index Name], ps.index_id, 
ps.index_type_desc, ps.avg_fragmentation_in_percent, 
ps.fragment_count, ps.page_count, i.fill_factor, i.has_filter, 
i.filter_definition, i.[allow_page_locks]
FROM sys.dm_db_index_physical_stats(DB_ID(),NULL, NULL, NULL , N'LIMITED') AS ps
INNER JOIN sys.indexes AS i WITH (NOLOCK)
ON ps.[object_id] = i.[object_id] 
AND ps.index_id = i.index_id
INNER JOIN sys.objects AS o WITH (NOLOCK)
ON i.[object_id] = o.[object_id]
WHERE ps.database_id = DB_ID()
AND ps.page_count > 2500
ORDER BY ps.avg_fragmentation_in_percent DESC OPTION (RECOMPILE);
------

-- Helps determine whether you have framentation in your relational indexes
-- and how effective your index maintenance strategy is


--- Index Read/Write stats (all tables in current DB) ordered by Reads  (Query 45) (Overall Index Usage - Reads)
SELECT OBJECT_NAME(i.[object_id]) AS [ObjectName], i.[name] AS [IndexName], i.index_id, 
       s.user_seeks, s.user_scans, s.user_lookups,
	   s.user_seeks + s.user_scans + s.user_lookups AS [Total Reads], 
	   s.user_updates AS [Writes],  
	   i.[type_desc] AS [Index Type], i.fill_factor AS [Fill Factor], i.has_filter, i.filter_definition, 
	   s.last_user_scan, s.last_user_lookup, s.last_user_seek
FROM sys.indexes AS i WITH (NOLOCK)
LEFT OUTER JOIN sys.dm_db_index_usage_stats AS s WITH (NOLOCK)
ON i.[object_id] = s.[object_id]
AND i.index_id = s.index_id
AND s.database_id = DB_ID()
WHERE OBJECTPROPERTY(i.[object_id],'IsUserTable') = 1
ORDER BY s.user_seeks + s.user_scans + s.user_lookups DESC OPTION (RECOMPILE); -- Order by reads
------

-- Show which indexes in the current database are most active for Reads


--- Index Read/Write stats (all tables in current DB) ordered by Writes  (Query 46) (Overall Index Usage - Writes)
SELECT OBJECT_NAME(i.[object_id]) AS [ObjectName], i.[name] AS [IndexName], i.index_id,
	   s.user_updates AS [Writes], s.user_seeks + s.user_scans + s.user_lookups AS [Total Reads], 
	   i.[type_desc] AS [Index Type], i.fill_factor AS [Fill Factor], i.has_filter, i.filter_definition,
	   s.last_system_update, s.last_user_update
FROM sys.indexes AS i WITH (NOLOCK)
LEFT OUTER JOIN sys.dm_db_index_usage_stats AS s WITH (NOLOCK)
ON i.[object_id] = s.[object_id]
AND i.index_id = s.index_id
AND s.database_id = DB_ID()
WHERE OBJECTPROPERTY(i.[object_id],'IsUserTable') = 1
ORDER BY s.user_updates DESC OPTION (RECOMPILE);						 -- Order by writes
------

-- Show which indexes in the current database are most active for Writes


-- Get in-memory OLTP index usage (Query 47) (XTP Index Usage)
SELECT OBJECT_NAME(i.[object_id]) AS [Object Name], i.index_id, i.[name] AS [Index Name],
       i.[type_desc], xis.scans_started, xis.scans_retries, 
	   xis.rows_touched, xis.rows_returned
FROM sys.dm_db_xtp_index_stats AS xis WITH (NOLOCK)
INNER JOIN sys.indexes AS i WITH (NOLOCK)
ON i.[object_id] = xis.[object_id] 
AND i.index_id = xis.index_id 
ORDER BY OBJECT_NAME(i.[object_id]) OPTION (RECOMPILE);
------

-- This gives you some index usage statistics for in-memory OLTP
-- Returns no data if you are not using in-memory OLTP

-- Guidelines for Using Indexes on Memory-Optimized Tables
-- https://bit.ly/2GCP8lF



-- Look at Columnstore index physical statistics (Query 48) (Columnstore Index Physical Stat)
SELECT OBJECT_NAME(ps.object_id) AS [TableName],  
	i.[name] AS [IndexName], ps.index_id, ps.partition_number,
	ps.delta_store_hobt_id, ps.state_desc, ps.total_rows, ps.size_in_bytes,
	ps.trim_reason_desc, ps.generation, ps.transition_to_compressed_state_desc,
	ps.has_vertipaq_optimization, ps.deleted_rows,
	100 * (ISNULL(ps.deleted_rows, 0))/ps.total_rows AS [Fragmentation]
FROM sys.dm_db_column_store_row_group_physical_stats AS ps WITH (NOLOCK)
INNER JOIN sys.indexes AS i WITH (NOLOCK)
ON ps.object_id = i.object_id 
AND ps.index_id = i.index_id
ORDER BY ps.object_id, ps.partition_number, ps.row_group_id OPTION (RECOMPILE);
------

-- sys.dm_db_column_store_row_group_physical_stats (Transact-SQL)
-- https://bit.ly/2q276XQ



-- Get lock waits for current database (Query 49) (Lock Waits)
SELECT o.name AS [table_name], i.name AS [index_name], ios.index_id, ios.partition_number,
		SUM(ios.row_lock_wait_count) AS [total_row_lock_waits], 
		SUM(ios.row_lock_wait_in_ms) AS [total_row_lock_wait_in_ms],
		SUM(ios.page_lock_wait_count) AS [total_page_lock_waits],
		SUM(ios.page_lock_wait_in_ms) AS [total_page_lock_wait_in_ms],
		SUM(ios.page_lock_wait_in_ms)+ SUM(row_lock_wait_in_ms) AS [total_lock_wait_in_ms]
FROM sys.dm_db_index_operational_stats(DB_ID(), NULL, NULL, NULL) AS ios
INNER JOIN sys.objects AS o WITH (NOLOCK)
ON ios.[object_id] = o.[object_id]
INNER JOIN sys.indexes AS i WITH (NOLOCK)
ON ios.[object_id] = i.[object_id] 
AND ios.index_id = i.index_id
WHERE o.[object_id] > 100
GROUP BY o.name, i.name, ios.index_id, ios.partition_number
HAVING SUM(ios.page_lock_wait_in_ms)+ SUM(row_lock_wait_in_ms) > 0
ORDER BY total_lock_wait_in_ms DESC OPTION (RECOMPILE);
------

-- This query is helpful for troubleshooting blocking and deadlocking issues



-- Look at UDF execution statistics (Query 50) (UDF Statistics)
SELECT OBJECT_NAME(object_id) AS [Function Name], total_worker_time,
       execution_count, total_elapsed_time,  
       total_elapsed_time/execution_count AS [avg_elapsed_time],  
       last_elapsed_time, last_execution_time, cached_time 
FROM sys.dm_exec_function_stats WITH (NOLOCK) 
WHERE database_id = DB_ID()
ORDER BY total_worker_time DESC OPTION (RECOMPILE); 
------


-- Helps you investigate scalar UDF performance issues

-- sys.dm_exec_function_stats (Transact-SQL)
-- https://bit.ly/2q1Q6BM




-- Get QueryStore Options for this database (Query 51) (QueryStore Options)
SELECT actual_state_desc, desired_state_desc,
       current_storage_size_mb, [max_storage_size_mb], 
	   query_capture_mode_desc, size_based_cleanup_mode_desc, 
	   wait_stats_capture_mode_desc, [flush_interval_seconds]
FROM sys.database_query_store_options WITH (NOLOCK) OPTION (RECOMPILE);
------

-- Added in SQL Server 2016
-- Requires that QueryStore is enabled for this database

-- Tuning Workload Performance with Query Store
-- https://bit.ly/1kHSl7w


-- Get highest aggregate duration queries over last hour (Query 52) (High Aggregate Duration Queries)
WITH AggregatedDurationLastHour
AS
(SELECT q.query_id, SUM(count_executions * avg_duration) AS total_duration,
   COUNT (distinct p.plan_id) AS number_of_plans
   FROM sys.query_store_query_text AS qt WITH (NOLOCK)
   INNER JOIN sys.query_store_query AS q WITH (NOLOCK)
   ON qt.query_text_id = q.query_text_id
   INNER JOIN sys.query_store_plan AS p WITH (NOLOCK)
   ON q.query_id = p.query_id
   INNER JOIN sys.query_store_runtime_stats AS rs WITH (NOLOCK)
   ON rs.plan_id = p.plan_id
   INNER JOIN sys.query_store_runtime_stats_interval AS rsi WITH (NOLOCK)
   ON rsi.runtime_stats_interval_id = rs.runtime_stats_interval_id
   WHERE rsi.start_time >= DATEADD(hour, -1, GETUTCDATE()) 
   AND rs.execution_type_desc = N'Regular'
   GROUP BY q.query_id),
OrderedDuration AS
(SELECT query_id, total_duration, number_of_plans, 
 ROW_NUMBER () OVER (ORDER BY total_duration DESC, query_id) AS RN
 FROM AggregatedDurationLastHour)
SELECT OBJECT_NAME(q.object_id) AS [Containing Object], qt.query_sql_text, 
od.total_duration AS [Total Duration (microsecs)], 
od.number_of_plans AS [Plan Count],
p.is_forced_plan, p.is_parallel_plan, p.is_trivial_plan,
q.query_parameterization_type_desc, p.[compatibility_level],
p.last_compile_start_time, q.last_execution_time,
CONVERT(xml, p.query_plan) AS query_plan_xml 
FROM OrderedDuration AS od 
INNER JOIN sys.query_store_query AS q WITH (NOLOCK)
ON q.query_id  = od.query_id
INNER JOIN sys.query_store_query_text AS qt WITH (NOLOCK)
ON q.query_text_id = qt.query_text_id
INNER JOIN sys.query_store_plan AS p WITH (NOLOCK)
ON q.query_id = p.query_id
WHERE od.RN <= 50 
ORDER BY total_duration DESC OPTION (RECOMPILE);
------

-- New for SQL Server 2016
-- Requires that QueryStore is enabled for this database


-- Get input buffer information for the current database (Query 53) (Input Buffer)
SELECT es.session_id, DB_NAME(es.database_id) AS [Database Name],
       es.login_time, es.cpu_time, es.logical_reads,
       es.[status], ib.event_info AS [Input Buffer]
FROM sys.dm_exec_sessions AS es WITH (NOLOCK)
CROSS APPLY sys.dm_exec_input_buffer(es.session_id, NULL) AS ib
WHERE es.database_id = DB_ID()
AND es.session_id > 50
AND es.session_id <> @@SPID OPTION (RECOMPILE);
------

-- Gives you input buffer information from all non-system sessions for the current database
-- Replaces DBCC INPUTBUFFER

-- New DMF for retrieving input buffer in SQL Server
-- https://bit.ly/2uHKMbz



-- Get any resumable index rebuild operation information (Query 54) (Resumable Index Rebuild)
SELECT OBJECT_NAME(iro.object_id) AS [Object Name], iro.index_id, iro.name AS [Index Name],
       iro.sql_text, iro.last_max_dop_used, iro.partition_number, iro.state_desc, iro.start_time, iro.percent_complete
FROM  sys.index_resumable_operations AS iro WITH (NOLOCK)
OPTION (RECOMPILE);
------ 

-- index_resumable_operations (Transact-SQL)
-- https://bit.ly/2pYSWqq


-- Get database automatic tuning options (Query 55) (Automatic Tuning Options)
SELECT [name], desired_state_desc, actual_state_desc, reason_desc
FROM sys.database_automatic_tuning_options WITH (NOLOCK)
OPTION (RECOMPILE);
------ 

-- sys.database_automatic_tuning_options (Transact-SQL)
-- https://bit.ly/2FHhLkL



-- Get geo-replication link status for all secondary databases (Query 56) (Geo-Replication Link Status)
SELECT link_guid, partner_server, partner_database, last_replication, 
       replication_lag_sec, replication_state_desc, role_desc, secondary_allow_connections_desc 
FROM sys.dm_geo_replication_link_status WITH (NOLOCK) OPTION (RECOMPILE);
------  

-- sys.dm_geo_replication_link_status (Azure SQL Database)
-- https://bit.ly/2GwIqC2



-- Retrieve some Azure SQL Database properties (Query 57) (Azure SQL DB Properties)
SELECT DATABASEPROPERTYEX (DB_NAME(DB_ID()), 'Edition') AS [Database Edition],
	   DATABASEPROPERTYEX (DB_NAME(DB_ID()), 'ServiceObjective') AS [Service Objective],
	   DATABASEPROPERTYEX (DB_NAME(DB_ID()), 'MaxSizeInBytes') AS [Max Size In Bytes],
	   DATABASEPROPERTYEX (DB_NAME(DB_ID()), 'IsXTPSupported') AS [Is XTP Supported]
	   OPTION (RECOMPILE);   
------  

-- DATABASEPROPERTYEX (Transact-SQL)
-- https://bit.ly/2ItexPg


-- These six Pluralsight Courses go into more detail about how to run these queries and interpret the results

-- Azure SQL Database: Diagnosing Performance Issues with DMVs
-- https://bit.ly/2meDRCN

-- SQL Server 2017: Diagnosing Performance Issues with DMVs
-- https://bit.ly/2FqCeti

-- SQL Server 2017: Diagnosing Configuration Issues with DMVs
-- https://bit.ly/2MSUDUL

-- SQL Server 2014 DMV Diagnostic Queries – Part 1 
-- https://bit.ly/2plxCer

-- SQL Server 2014 DMV Diagnostic Queries – Part 2
-- https://bit.ly/2IuJpzI

-- SQL Server 2014 DMV Diagnostic Queries – Part 3
-- https://bit.ly/2FIlCPb



-- Microsoft Visual Studio Dev Essentials
-- https://bit.ly/2qjNRxi

-- Microsoft Azure Learn
-- https://bit.ly/2O0Hacc