Question

在我们项目的DataBase中，我们只有一个表，其中有超过10个lac记录。

这个特殊的表使我们的Web应用程序的性能太慢。

Answer 1

请问您能提供更多详情吗？您目前分享的信息不足以为您提供良好的回复。可能有很多事情可能导致性能问题。在寻找解决方案之前，您需要先缩小范围，然后先清除问题。

SELECT @@ VERSION获取完整版
这个盒子里有多少内存？
分享以下查询的详细信息

    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')

分享以下缺失索引DMV的详细信息，看看您是否有任何涉及上述表格的查询。


SET TRANSACTION ISOLATION LEVEL READ UNCOMMITTED;
WITH XMLNAMESPACES

   (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

您是否检查了查询统计信息是否存在高CPU使用率，逻辑读取数，高执行次数？


-- Cached SP's By Execution Count
SELECT TOP (100) OBJECT_NAME(qt.objectid) AS 'SP Name', qs.execution_count AS 'Execution Count',

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;

-- 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;

-- 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;

你看过WAIT STATS了吗？


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

您是否在系统中看到阻止？

一个表包含超过10个lacs记录

1 个答案: