SQL сервер 2008: обслуживание, анализ производительности

Скрипты не мои, собраны с ресурсов по MS SQL. Опубликованы скрипты и запросы, которыми сам часто пользуюсь

Большинство скриптов статьи и многие другие представлены в конфигурации:

 Обновление однотипных конфигураций, работа с SQL и другие регламентные операции

Обслуживание индексов

Степень фрагментации индексов

Первый запрос показывает текущую фрагментацию индексов базы

SELECT TOP 100
       DatbaseName = DB_NAME(),
       TableName = OBJECT_NAME(s.[object_id]),
       IndexName = i.name,
       i.type_desc,
       [Fragmentation %] = ROUND(avg_fragmentation_in_percent,2),
       page_count,
       partition_number,
       'alter index [' + i.name + '] on [' + sh.name + '].['+ OBJECT_NAME(s.[object_id]) + '] REBUILD' + case
                                                                                                           when p.data_space_id is not null then ' PARTITION = '+convert(varchar(100),partition_number)
                                                                                                           else ''
                                                                                                         end + ' with(maxdop = 4,  SORT_IN_TEMPDB = on)' [sql]
  FROM sys.dm_db_index_physical_stats(db_id(),null, null, null, null) s
  INNER JOIN sys.indexes as i ON s.[object_id] = i.[object_id] AND
                                 s.index_id = i.index_id
  left join sys.partition_schemes as p on i.data_space_id = p.data_space_id
  left join sys.objects o on  s.[object_id] = o.[object_id]
  left join sys.schemas as sh on sh.[schema_id] = o.[schema_id]
  WHERE s.database_id = DB_ID() AND
        i.name IS NOT NULL AND
        OBJECTPROPERTY(s.[object_id], 'IsMsShipped') = 0 and
        page_count > 100 and
        avg_fragmentation_in_percent > 10
  ORDER BY 4, page_count

Результат запроса:

Реорганизация/Перестроение индексов

Скрипт, приведенный ниже, запускает реорганизацию либо перестроение индексов для таблиц базы исходя из текущей дефрагментации (отбирает индексы, дефрагментированные более 10%, затем. если фрагментация менее 30% - реорганизация индексов, если более или равно 30% - перестроение). Я бы рекомендовал использовать как регламентное задание.

USE [myDB]
GO

SET NOCOUNT ON;
SET QUOTED_IDENTIFIER ON;
DECLARE @objectid int;
DECLARE @indexid int;
DECLARE @partitioncount bigint;
DECLARE @schemaname nvarchar(130);
DECLARE @objectname nvarchar(130);
DECLARE @indexname nvarchar(130);
DECLARE @partitionnum bigint;
DECLARE @partitions bigint;
DECLARE @frag float;
DECLARE @command nvarchar(4000);

-- Conditionally select tables and indexes from the sys.dm_db_index_physical_stats function
-- and convert object and index IDs to names.

SELECT
    object_id AS objectid,
    index_id AS indexid,
    partition_number AS partitionnum,
    avg_fragmentation_in_percent AS frag
INTO #work_to_do
FROM sys.dm_db_index_physical_stats (DB_ID(), NULL, NULL , NULL, 'LIMITED')
WHERE avg_fragmentation_in_percent > 10.0 AND index_id > 0;

-- Declare the cursor for the list of partitions to be processed.
DECLARE partitions CURSOR FOR SELECT * FROM #work_to_do;

-- Open the cursor.
OPEN partitions;

-- Loop through the partitions.
WHILE (1=1)
    BEGIN;
        FETCH NEXT
          FROM partitions
          INTO @objectid, @indexid, @partitionnum, @frag;
        IF @@FETCH_STATUS < 0 BREAK;
        SELECT @objectname = QUOTENAME(o.name), @schemaname = QUOTENAME(s.name)
        FROM sys.objects AS o
        JOIN sys.schemas as s ON s.schema_id = o.schema_id
        WHERE o.object_id = @objectid;

        SELECT @indexname = QUOTENAME(name)
        FROM sys.indexes
        WHERE  object_id = @objectid AND index_id = @indexid;
        SELECT @partitioncount = count (*)
        FROM sys.partitions
        WHERE object_id = @objectid AND index_id = @indexid;

 -- 30 is an arbitrary decision point at which to switch between reorganizing and rebuilding.
         IF @frag < 30.0
            SET @command = N'ALTER INDEX ' + @indexname + N' ON ' + @schemaname + N'.' + @objectname + N' REORGANIZE';
         IF @frag >= 30.0
            SET @command = N'ALTER INDEX ' + @indexname + N' ON ' + @schemaname + N'.' + @objectname + N' REBUILD';
         IF @partitioncount > 1
             SET @command = @command + N' PARTITION=' + CAST(@partitionnum AS nvarchar(10));

        EXEC (@command);

        PRINT N'Executed: ' + @command;

    END;

-- Close and deallocate the cursor.
CLOSE partitions;
DEALLOCATE partitions;

-- Drop the temporary table.
DROP TABLE #work_to_do;
GO

SET QUOTED_IDENTIFIER OFF;
GO

Отсутствующие индексы

Общее количество отсутствующих индексов в базах:

SELECT [DatabaseName] = DB_NAME(database_id),
       [Number Indexes Missing] = count(*) 
FROM sys.dm_db_missing_index_details
GROUP BY DB_NAME(database_id)
ORDER BY 2 DESC

Отсутствующие индексы, вызывающие высокие издержки:

SELECT TOP 100 
       [Total Cost] = ROUND(avg_total_user_cost * avg_user_impact * (user_seeks + user_scans),0),
       avg_user_impact,
       TableName = statement,
       [EqualityUsage] = equality_columns,
       [InequalityUsage] = inequality_columns,
       [Include Cloumns] = included_columns
  FROM sys.dm_db_missing_index_groups g 
  INNER JOIN sys.dm_db_missing_index_group_stats s ON s.group_handle = g.index_group_handle 
  INNER JOIN sys.dm_db_missing_index_details d ON d.index_handle = g.index_handle
  WHERE database_id = DB_ID()
  ORDER BY [Total Cost] DESC

Результат запроса:

К анализу недостающих индексов можно еще добавить активность таблиц на чтение/запись:

-- Table Reads and Writes
-- Heap tables out of scope for this query. Heaps do not have indexes.
-- Only lists tables referenced since the last server restart
SELECT  @@ServerName AS ServerName ,
        DB_NAME() AS DBName ,
        OBJECT_NAME(ddius.object_id) AS TableName ,
        SUM(ddius.user_seeks + ddius.user_scans + ddius.user_lookups)
                                                               AS Reads ,
        SUM(ddius.user_updates) AS Writes ,
        SUM(ddius.user_seeks + ddius.user_scans + ddius.user_lookups
            + ddius.user_updates) AS [Reads&Writes] ,
        ( SELECT    DATEDIFF(s, create_date, GETDATE()) / 86400.0
          FROM      master.sys.databases
          WHERE     name = 'tempdb'
        ) AS SampleDays ,
        ( SELECT    DATEDIFF(s, create_date, GETDATE()) AS SecoundsRunnig
          FROM      master.sys.databases
          WHERE     name = 'tempdb'
        ) AS SampleSeconds
FROM    sys.dm_db_index_usage_stats ddius
        INNER JOIN sys.indexes i ON ddius.object_id = i.object_id
                                     AND i.index_id = ddius.index_id
WHERE   OBJECTPROPERTY(ddius.object_id, 'IsUserTable') = 1
        AND ddius.database_id = DB_ID()
GROUP BY OBJECT_NAME(ddius.object_id)
ORDER BY [Reads&Writes] DESC;
GO

Результат запроса:

Неиспользуемые индексы

-- Create required table structure only.
-- Note: this SQL must be the same as in the Database loop given in the following step.
SELECT TOP 1
        DatabaseName = DB_NAME()
        ,TableName = OBJECT_NAME(s.[object_id])
        ,IndexName = i.name
        ,user_updates    
        ,system_updates    
        -- Useful fields below:
        --, *
INTO #TempUnusedIndexes
FROM   sys.dm_db_index_usage_stats s 
INNER JOIN sys.indexes i ON  s.[object_id] = i.[object_id] 
    AND s.index_id = i.index_id 
WHERE  s.database_id = DB_ID()
    AND OBJECTPROPERTY(s.[object_id], 'IsMsShipped') = 0
    AND    user_seeks = 0
    AND user_scans = 0 
    AND user_lookups = 0
    AND s.[object_id] = -999  -- Dummy value to get table structure.
;

-- Loop around all the databases on the server.
EXEC sp_MSForEachDB    'USE [?]; 
-- Table already exists.
INSERT INTO #TempUnusedIndexes 
SELECT TOP 10    
        DatabaseName = DB_NAME()
        ,TableName = OBJECT_NAME(s.[object_id])
        ,IndexName = i.name
        ,user_updates    
        ,system_updates    
FROM   sys.dm_db_index_usage_stats s 
INNER JOIN sys.indexes i ON  s.[object_id] = i.[object_id] 
    AND s.index_id = i.index_id 
WHERE  s.database_id = DB_ID()
    AND OBJECTPROPERTY(s.[object_id], ''IsMsShipped'') = 0
    AND    user_seeks = 0
    AND user_scans = 0 
    AND user_lookups = 0
    AND i.name IS NOT NULL    -- Ignore HEAP indexes.
ORDER BY user_updates DESC
;
'

-- Select records.
SELECT TOP 100 * FROM #TempUnusedIndexes ORDER BY [user_updates] DESC
-- Tidy up.
DROP TABLE #TempUnusedIndexes

Результат:

Индексы с высокими издержками

-- Create required table structure only.
-- Note: this SQL must be the same as in the Database loop given in the following step.
SELECT TOP 1
        [Maintenance cost]  = (user_updates + system_updates)
        ,[Retrieval usage] = (user_seeks + user_scans + user_lookups)
        ,DatabaseName = DB_NAME()
        ,TableName = OBJECT_NAME(s.[object_id])
        ,IndexName = i.name
INTO #TempMaintenanceCost
FROM   sys.dm_db_index_usage_stats s 
INNER JOIN sys.indexes i ON  s.[object_id] = i.[object_id] 
    AND s.index_id = i.index_id
WHERE s.database_id = DB_ID() 
    AND OBJECTPROPERTY(s.[object_id], 'IsMsShipped') = 0
    AND (user_updates + system_updates) > 0 -- Only report on active rows.
    AND s.[object_id] = -999  -- Dummy value to get table structure.
;

-- Loop around all the databases on the server.
EXEC sp_MSForEachDB    'USE [?]; 
-- Table already exists.
INSERT INTO #TempMaintenanceCost 
SELECT TOP 10
        [Maintenance cost]  = (user_updates + system_updates)
        ,[Retrieval usage] = (user_seeks + user_scans + user_lookups)
        ,DatabaseName = DB_NAME()
        ,TableName = OBJECT_NAME(s.[object_id])
        ,IndexName = i.name
FROM   sys.dm_db_index_usage_stats s 
INNER JOIN sys.indexes i ON  s.[object_id] = i.[object_id] 
    AND s.index_id = i.index_id
WHERE s.database_id = DB_ID() 
    AND i.name IS NOT NULL    -- Ignore HEAP indexes.
    AND OBJECTPROPERTY(s.[object_id], ''IsMsShipped'') = 0
    AND (user_updates + system_updates) > 0 -- Only report on active rows.
ORDER BY [Maintenance cost]  DESC
;
'

-- Select records.
SELECT TOP 100 * FROM #TempMaintenanceCost 
ORDER BY [Maintenance cost]  DESC
-- Tidy up.
DROP TABLE #TempMaintenanceCost

Пример работы:

Часто используемые индексы

-- Create required table structure only.
-- Note: this SQL must be the same as in the Database loop given in the -- following step.
SELECT TOP 1
        [Usage] = (user_seeks + user_scans + user_lookups)
        ,DatabaseName = DB_NAME()
        ,TableName = OBJECT_NAME(s.[object_id])
        ,IndexName = i.name
INTO #TempUsage
FROM   sys.dm_db_index_usage_stats s 
INNER JOIN sys.indexes i ON s.[object_id] = i.[object_id] 
    AND s.index_id = i.index_id 
WHERE   s.database_id = DB_ID() 
    AND OBJECTPROPERTY(s.[object_id], 'IsMsShipped') = 0
    AND (user_seeks + user_scans + user_lookups) > 0 
-- Only report on active rows.
    AND s.[object_id] = -999  -- Dummy value to get table structure.
;

-- Loop around all the databases on the server.
EXEC sp_MSForEachDB    'USE [?]; 
-- Table already exists.
INSERT INTO #TempUsage 
SELECT TOP 10
        [Usage] = (user_seeks + user_scans + user_lookups)
        ,DatabaseName = DB_NAME()
        ,TableName = OBJECT_NAME(s.[object_id])
        ,IndexName = i.name
FROM   sys.dm_db_index_usage_stats s 
INNER JOIN sys.indexes i ON s.[object_id] = i.[object_id] 
    AND s.index_id = i.index_id 
WHERE   s.database_id = DB_ID() 
    AND i.name IS NOT NULL    -- Ignore HEAP indexes.
    AND OBJECTPROPERTY(s.[object_id], ''IsMsShipped'') = 0
    AND (user_seeks + user_scans + user_lookups) > 0 -- Only report on active rows.
ORDER BY [Usage]  DESC
;
'

-- Select records.
SELECT TOP 100 * FROM #TempUsage ORDER BY [Usage] DESC
-- Tidy up.
DROP TABLE #TempUsage

Пример работы:

Планы запросов

Самые тяжелые запросы

SELECT TOP 10 SUBSTRING(qt.TEXT, (qs.statement_start_offset/2)+1,
((CASE qs.statement_end_offset
WHEN -1 THEN DATALENGTH(qt.TEXT)
ELSE qs.statement_end_offset
END - qs.statement_start_offset)/2)+1),
qp.query_plan,
qs.execution_count,
qs.total_logical_reads, qs.last_logical_reads,
qs.total_logical_writes, qs.last_logical_writes,
qs.total_worker_time,
qs.last_worker_time,
qs.total_elapsed_time/1000000 total_elapsed_time_in_S,
qs.last_elapsed_time/1000000 last_elapsed_time_in_S,
qs.last_execution_time

FROM sys.dm_exec_query_stats qs
CROSS APPLY sys.dm_exec_sql_text(qs.sql_handle) qt
CROSS APPLY sys.dm_exec_query_plan(qs.plan_handle) qp
ORDER BY qs.total_logical_reads DESC -- logical reads
-- ORDER BY qs.total_logical_writes DESC -- logical writes
-- ORDER BY qs.total_worker_time DESC -- CPU time

Пример:

Параллельные планы запросов

SET TRANSACTION ISOLATION LEVEL READ UNCOMMITTED;

WITH XMLNAMESPACES

(DEFAULT

  'http://schemas.microsoft.com/sqlserver/2004/07/showplan')

SELECT

  query_plan AS CompleteQueryPlan,

  n.value('(@StatementText)[1]', 'VARCHAR(4000)')

  AS StatementText, n.value('(@StatementSubTreeCost)[1]',

  'VARCHAR(128)') AS StatementSubTreeCost, dm_ecp.usecounts

FROM sys.dm_exec_cached_plans AS dm_ecp

CROSS APPLY sys.dm_exec_query_plan(plan_handle) AS dm_eqp

CROSS APPLY query_plan.nodes

  ('/ShowPlanXML/BatchSequence/Batch/Statements/StmtSimple')

  AS qp(n)

WHERE

n.query('.').exist('//RelOp[@PhysicalOp="Parallelism"]') = 1

GO

Пример:

Пример плана запроса:

Статистики ожиданий

В этом запросе исключены незначимые типы ожиданий:

SELECT TOP 10
        wait_type ,
        max_wait_time_ms wait_time_ms ,
        signal_wait_time_ms ,
        wait_time_ms - signal_wait_time_ms AS resource_wait_time_ms ,
        100.0 * wait_time_ms / SUM(wait_time_ms) OVER ( )
                                    AS percent_total_waits ,
        100.0 * signal_wait_time_ms / SUM(signal_wait_time_ms) OVER ( )
                                    AS percent_total_signal_waits ,
        100.0 * ( wait_time_ms - signal_wait_time_ms )
        / SUM(wait_time_ms) OVER ( ) AS percent_total_resource_waits
FROM    sys.dm_os_wait_stats 
WHERE   wait_time_ms > 0 -- уберем нулевые задержки 
        AND wait_type NOT IN 
( 'SLEEP_TASK', 'BROKER_TASK_STOP', 'BROKER_TO_FLUSH',
  'SQLTRACE_BUFFER_FLUSH','CLR_AUTO_EVENT', 'CLR_MANUAL_EVENT',
  'LAZYWRITER_SLEEP', 'SLEEP_SYSTEMTASK', 'SLEEP_BPOOL_FLUSH',
  'BROKER_EVENTHANDLER', 'XE_DISPATCHER_WAIT', 'FT_IFTSHC_MUTEX',
  'CHECKPOINT_QUEUE', 'FT_IFTS_SCHEDULER_IDLE_WAIT',
  'BROKER_TRANSMITTER', 'FT_IFTSHC_MUTEX', 'KSOURCE_WAKEUP',
  'LAZYWRITER_SLEEP', 'LOGMGR_QUEUE', 'ONDEMAND_TASK_QUEUE',
  'REQUEST_FOR_DEADLOCK_SEARCH', 'XE_TIMER_EVENT', 'BAD_PAGE_PROCESS',
  'DBMIRROR_EVENTS_QUEUE', 'BROKER_RECEIVE_WAITFOR',
  'PREEMPTIVE_OS_GETPROCADDRESS', 'PREEMPTIVE_OS_AUTHENTICATIONOPS',
  'WAITFOR', 'DISPATCHER_QUEUE_SEMAPHORE', 'XE_DISPATCHER_JOIN',
  'RESOURCE_QUEUE' )
ORDER BY wait_time_ms DESC

Расшифровка статистик ожиданий

Пример результата:

Следует иметь ввиду, что статистика не сохраняется при перезапуске SQL Server, и все данные накапливаются с момента последнего сброса статистики или перезапуска сервера.

Очистка статистик ожидания:

DBCC SQLPERF(waitstats, CLEAR)
GO

Рабочие протоколы

select program_name,net_transport
from sys.dm_exec_sessions as t1
left join sys.dm_exec_connections AS t2 ON t1.session_id=t2.session_id
where not t1.program_name is null

Пример: