таблица содержит более 10 записей lacs

Question

В базе данных нашего проекта у нас есть только одна таблица, которая содержит более 10 записей lac.

эта конкретная таблица делает наше веб-приложение слишком медленным в производительности.

Answer 1

Можете ли вы добавить более подробную информацию, пожалуйста?Информации, которой вы поделились, недостаточно, чтобы дать вам хорошие ответы.Там может быть много вещей, которые могут привести к проблемам с производительностью.Прежде чем искать решение, вам необходимо четко сузить и изолировать проблему.

1. ВЫБЕРИТЕ @@ ВЕРСИЮ, чтобы получить полную версию
2. Сколько памяти находится в этом окне?1006 *
3. Поделитесь сведениями из запроса ниже

<code>    SELECT 
        object_name(s.object_id) AS 'Table Name'
        , i.name AS 'Index Name'
        , i.index_id
        , user_updates AS 'Total Writes'
        , user_seeks
        , user_scans 
        , user_lookups
    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
    WHERE objectproperty(s.object_id,'IsUserTable') = 1
    AND s.database_id = db_id()
    AND i.object_id = object_id('YourTableName')

1. Поделитесь сведениями о нижеприведенных индексах DMV и посмотрите,есть какие-либо запросы, которые касаются таблицы, которую вы упомянули выше.

   <code>
   SET TRANSACTION ISOLATION LEVEL READ UNCOMMITTED;
   WITH XMLNAMESPACES<br>
      (DEFAULT 'http://schemas.microsoft.com/sqlserver/2004/07/showplan') 
   SELECT TOP 25--ecp.plan_handle,
           DENSE_RANK() OVER ( ORDER BY ecp.plan_handle ) AS ArbitraryPlanNumber ,
           n.value('(@StatementSubTreeCost)[1]', 'VARCHAR(128)')
           * ISNULL(n.value('(./QueryPlan/MissingIndexes/MissingIndexGroup/@Impact)[1]','float'), 0)
           * ecp.usecounts AS Improvement ,
           query_plan AS CompleteQueryPlan ,
           n.value('(@StatementId)[1]', 'float') AS StatementID ,
           n.value('(@StatementText)[1]', 'VARCHAR(4000)') AS StatementText ,
           n.value('(@StatementSubTreeCost)[1]', 'VARCHAR(128)') AS StatementSubTreeCost ,
           n.query('./QueryPlan/MissingIndexes') MissingIndex ,
           n.value('(./QueryPlan/MissingIndexes/MissingIndexGroup/@Impact)[1]','float') IndexImpact ,
           ecp.usecounts
   FROM    sys.dm_exec_cached_plans AS ecp
           CROSS APPLY sys.dm_exec_query_plan(plan_handle) AS eqp
           CROSS APPLY query_plan.nodes('/ShowPlanXML/BatchSequence/Batch/Statements/StmtSimple')
           AS qn ( n )
   WHERE   n.value('(./QueryPlan/MissingIndexes/MissingIndexGroup/@Impact)[1]','float') IS NOT NULL AND
           --ecp.usecounts > 100 AND
           eqp.query_plan.exist('declare default element namespace "http://schemas.microsoft.com/sqlserver/2004/07/showplan"; 
            /ShowPlanXML/BatchSequence/Batch/Statements/StmtSimple/QueryPlan/MissingIndexes') = 1 
   ORDER BY Improvement DESC

2. Проверяли ли вы статистику запросов на предмет высокой загрузки ЦП, логических чтений, большого числа выполнений?

   <code>
   -- Cached SP's By Execution Count
   SELECT TOP (100) OBJECT_NAME(qt.objectid) AS 'SP Name', qs.execution_count AS 'Execution Count',<br>
   qs.execution_count/DATEDIFF(Second, qs.creation_time, GetDate()) AS 'Calls/Second',
   qs.total_worker_time/qs.execution_count AS 'AvgWorkerTime',
   qs.total_worker_time AS 'TotalWorkerTime',
   qs.total_elapsed_time/qs.execution_count AS 'AvgElapsedTime',
   qs.max_logical_reads, qs.max_logical_writes, qs.total_physical_reads, 
   DATEDIFF(Minute, qs.creation_time, GetDate()) AS 'Age in Cache'
   FROM sys.dm_exec_query_stats AS qs
   CROSS APPLY sys.dm_exec_sql_text(qs.sql_handle) AS qt
   WHERE qt.dbid = db_id() -- Filter by current database
   ORDER BY qs.execution_count DESC;</p>
   
   <p>-- Cached SP's By Worker Time
   SELECT TOP (50) OBJECT_NAME(qt.objectid) AS 'SP Name', qs.total_worker_time AS 'TotalWorkerTime', 
   qs.total_worker_time/qs.execution_count AS 'AvgWorkerTime',
   qs.execution_count AS 'Execution Count', 
   ISNULL(qs.execution_count/DATEDIFF(Second, qs.creation_time, GetDate()), 0) AS 'Calls/Second',
   ISNULL(qs.total_elapsed_time/qs.execution_count, 0) AS 'AvgElapsedTime', 
   qs.max_logical_reads, qs.max_logical_writes, 
   DATEDIFF(Minute, qs.creation_time, GetDate()) AS 'Age in Cache in Minutes'
   FROM sys.dm_exec_query_stats AS qs
   CROSS APPLY sys.dm_exec_sql_text(qs.sql_handle) AS qt
   WHERE qt.dbid = db_id() -- Filter by current database
   ORDER BY qs.total_worker_time DESC;</p>
   
   <p>-- Cached SP's By Logical Reads
   SELECT TOP (50) OBJECT_NAME(qt.objectid) AS 'SP Name', total_logical_reads, 
   qs.execution_count AS 'Execution Count', total_logical_reads/qs.execution_count AS 'AvgLogicalReads',
   qs.execution_count/DATEDIFF(Second, qs.creation_time, GetDate()) AS 'Calls/Second', 
   qs.total_worker_time/qs.execution_count AS 'AvgWorkerTime',
   qs.total_worker_time AS 'TotalWorkerTime',
   qs.total_elapsed_time/qs.execution_count AS 'AvgElapsedTime',
   qs.total_logical_writes,
   qs.max_logical_reads, qs.max_logical_writes, qs.total_physical_reads, 
   DATEDIFF(Minute, qs.creation_time, GetDate()) AS 'Age in Cache'
   FROM sys.dm_exec_query_stats AS qs
   CROSS APPLY sys.dm_exec_sql_text(qs.sql_handle) AS qt
   WHERE qt.dbid = db_id() -- Filter by current database
   ORDER BY total_logical_reads DESC;

3. Вы смотрели статистику ожидания?

   <code>
   WITH Waits AS
   (SELECT wait_type, wait_time_ms / 1000. AS wait_time_s,
       100. * wait_time_ms / SUM(wait_time_ms) OVER() AS pct,
       ROW_NUMBER() OVER(ORDER BY wait_time_ms DESC) AS rn
    FROM sys.dm_os_wait_stats
    WHERE wait_type NOT IN( 'BROKER_TASK_STOP', 
     'SQLTRACE_BUFFER_FLUSH', 'CLR_AUTO_EVENT', 'CLR_MANUAL_EVENT', 'BROKER_TRANSMITTER',
     'LAZYWRITER_SLEEP', 'SQLTRACE_WAIT_ENTRIES')) -- filter out additional irrelevant waits
   SELECT W1.wait_type, 
     CAST(W1.wait_time_s AS DECIMAL(12, 2)) AS wait_time_s,
     CAST(W1.pct AS DECIMAL(12, 2)) AS pct,
     CAST(SUM(W2.pct) AS DECIMAL(12, 2)) AS running_pct
   FROM Waits AS W1
   INNER JOIN Waits AS W2
   ON W2.rn <= W1.rn
   GROUP BY W1.rn, W1.wait_type, W1.wait_time_s, W1.pct
   HAVING SUM(W2.pct) - W1.pct < 99; -- percentage threshold

4. Видите ли вы блокировку в вашей системе?