SQL 长时间运行的查询/最大化服务器资源，例如内存/CPU答案

【问题标题】：SQL Long running query / maxing out server resource e.g. RAM/CPUSQL 长时间运行的查询/最大化服务器资源，例如内存/CPU
【发布时间】：2018-10-17 13:50:29
【问题描述】：

我最初发布了以下线程SQL Query - long running / taking up CPU resource

我的问题是查询的 SARGABILITY，已经解决了这个问题（请参阅上一个线程，但简而言之，我使用了很多绕过索引扫描的 ISNULL 函数）我现在遇到了更多问题。

我的 SQL 服务器设置如下：

并行性的成本阈值 5

最大并行度 0

我的查询仍然需要 2:13 才能运行并导致 CPU / 内存峰值，我有一个功能强大的服务器，例如64GB RAM，所以资源不是问题。请参阅下面的查询：

WITH CTE AS 
(
    SELECT R.Id AS ResultId,
        r.JobId,
        r.CandidateId,
        R.Email,
        CAST(0 AS BIT) AS EmailSent,
        NULL AS EmailSentDate,
        'PICKUP' AS EmailStatus,
        GETDATE() AS CreateDate,
        C.Id AS UserId,
        C.Email AS UserEmail,
        NULL AS Subject
    FROM RESULTS R
    INNER JOIN JOB J ON R.JobId = J.Id
    INNER JOIN Consultant C ON J.UserId = C.Id
    WHERE 
        J.DCApproved = 1
        AND (J.Closed = 0 OR J.Closed IS NULL)
        AND (R.Email <> '' OR R.Email IS NOT NULL)
        AND (R.EmailSent = 0 OR R.EmailSent IS NULL)
        AND R.EmailSentDate IS NULL -- email has not been sent
        AND (R.EmailStatus = '' OR R.EmailStatus IS NULL)
        AND (R.IsEmailSubscribe = 'True' OR R.IsEmailSubscribe IS NULL)
        -- not already been emailed for this job
        AND NOT EXISTS (
            SELECT SMTP.Email
            FROM SMTP_Production SMTP
            WHERE SMTP.JobId = R.JobId AND SMTP.CandidateId = R.CandidateId
        )
        -- not unsubscribed
        AND NOT EXISTS (        
            SELECT u.Id FROM Unsubscribe u
            WHERE (u.EmailAddress = R.Email OR (u.EmailAddress IS NULL AND R.Email IS NULL)) 
        )
        AND NOT EXISTS (
            SELECT SMTP.Id FROM SMTP_Production SMTP
            WHERE SMTP.EmailStatus = 'PICKUP' AND SMTP.CandidateId = R.CandidateId
        )   
        AND C.Id NOT IN (
            -- LIST OF IDS
        )
        AND J.Id NOT IN (
            -- LIST OF IDS
        )
        AND J.ClientId NOT IN 
        (
            -- LIST OF IDS
        )
)

SELECT 
    CTE.ResultId,
    CTE.JobId,
    CTE.CandidateId,
    CTE.Email,
    CTE.EmailSent,
    CTE.EmailSentDate,
    CTE.EmailStatus,
    CTE.CreateDate,
    CTE.UserId,
    CTE.UserEmail,
    NULL
FROM CTE
  INNER JOIN 
    (
        SELECT *, row_number() over(partition by CTE.Email, CTE.CandidateId order by CTE.EmailSentDate desc) as rn
        FROM CTE

    ) DCTE ON CTE.ResultId = DCTE.ResultId AND DCTE.rn = 1

请参阅下面结果表的索引，下面的某些内容似乎不正确：

/****** Object:  Index [_dta_index_Results_7_2107154552__K35_K2_K3_K34_K36_K8_K33_K1]    Script Date: 17/10/2018 15:06:18 ******/
CREATE NONCLUSTERED INDEX [_dta_index_Results_7_2107154552__K35_K2_K3_K34_K36_K8_K33_K1] ON [dbo].[Results]
(
    [EmailSentDate] ASC,
    [JobId] ASC,
    [AryaCandidateId] ASC,
    [EmailSent] ASC,
    [EmailStatus] ASC,
    [Email] ASC,
    [IsEmailSubscribe] ASC,
    [Id] ASC
)WITH (PAD_INDEX = OFF, STATISTICS_NORECOMPUTE = OFF, SORT_IN_TEMPDB = OFF, DROP_EXISTING = OFF, ONLINE = OFF, ALLOW_ROW_LOCKS = ON, ALLOW_PAGE_LOCKS = ON) ON [PRIMARY]
GO
SET ANSI_PADDING ON
GO
/****** Object:  Index [ACI_CMT_APPLICANTS]    Script Date: 17/10/2018 15:06:18 ******/
CREATE NONCLUSTERED INDEX [ACI_CMT_APPLICANTS] ON [dbo].[Results]
(
    [Email] ASC
)
INCLUDE (   [Id],
    [AryaCandidateId]) WITH (PAD_INDEX = OFF, STATISTICS_NORECOMPUTE = OFF, SORT_IN_TEMPDB = OFF, DROP_EXISTING = OFF, ONLINE = OFF, ALLOW_ROW_LOCKS = ON, ALLOW_PAGE_LOCKS = ON) ON [PRIMARY]
GO
/****** Object:  Index [ACI_Job]    Script Date: 17/10/2018 15:06:18 ******/
CREATE NONCLUSTERED INDEX [ACI_Job] ON [dbo].[Results]
(
    [AryaCandidateId] ASC,
    [JobId] ASC
)WITH (PAD_INDEX = OFF, STATISTICS_NORECOMPUTE = OFF, SORT_IN_TEMPDB = OFF, DROP_EXISTING = OFF, ONLINE = OFF, ALLOW_ROW_LOCKS = ON, ALLOW_PAGE_LOCKS = ON) ON [PRIMARY]
GO
/****** Object:  Index [ACI_Results]    Script Date: 17/10/2018 15:06:18 ******/
CREATE NONCLUSTERED INDEX [ACI_Results] ON [dbo].[Results]
(
    [AryaCandidateId] ASC
)WITH (PAD_INDEX = OFF, STATISTICS_NORECOMPUTE = OFF, SORT_IN_TEMPDB = OFF, DROP_EXISTING = OFF, ONLINE = OFF, ALLOW_ROW_LOCKS = ON, ALLOW_PAGE_LOCKS = ON) ON [PRIMARY]
GO
SET ANSI_PADDING ON
GO
/****** Object:  Index [gen_smtp_auto]    Script Date: 17/10/2018 15:06:18 ******/
CREATE NONCLUSTERED INDEX [gen_smtp_auto] ON [dbo].[Results]
(
    [EmailSentDate] ASC,
    [Email] ASC,
    [IsEmailSubscribe] ASC,
    [EmailSent] ASC,
    [EmailStatus] ASC
)
INCLUDE (   [Id],
    [JobId],
    [AryaCandidateId]) WITH (PAD_INDEX = OFF, STATISTICS_NORECOMPUTE = OFF, SORT_IN_TEMPDB = OFF, DROP_EXISTING = OFF, ONLINE = OFF, ALLOW_ROW_LOCKS = ON, ALLOW_PAGE_LOCKS = ON) ON [PRIMARY]
GO
SET ANSI_PADDING ON
GO
/****** Object:  Index [Hot]    Script Date: 17/10/2018 15:06:18 ******/
CREATE NONCLUSTERED INDEX [Hot] ON [dbo].[Results]
(
    [JobId] ASC,
    [Action] ASC
)
INCLUDE (   [Engaged]) WITH (PAD_INDEX = OFF, STATISTICS_NORECOMPUTE = OFF, SORT_IN_TEMPDB = OFF, DROP_EXISTING = OFF, ONLINE = OFF, ALLOW_ROW_LOCKS = ON, ALLOW_PAGE_LOCKS = ON) ON [PRIMARY]
GO
/****** Object:  Index [IX_Results]    Script Date: 17/10/2018 15:06:18 ******/
CREATE NONCLUSTERED INDEX [IX_Results] ON [dbo].[Results]
(
    [Id] ASC,
    [JobId] ASC
)WITH (PAD_INDEX = OFF, STATISTICS_NORECOMPUTE = OFF, SORT_IN_TEMPDB = OFF, DROP_EXISTING = OFF, ONLINE = OFF, ALLOW_ROW_LOCKS = ON, ALLOW_PAGE_LOCKS = ON) ON [PRIMARY]
GO
/****** Object:  Index [IX_Results_1]    Script Date: 17/10/2018 15:06:18 ******/
CREATE NONCLUSTERED INDEX [IX_Results_1] ON [dbo].[Results]
(
    [Id] ASC,
    [JobId] ASC,
    [AryaCandidateId] ASC
)WITH (PAD_INDEX = OFF, STATISTICS_NORECOMPUTE = OFF, SORT_IN_TEMPDB = OFF, DROP_EXISTING = OFF, ONLINE = OFF, ALLOW_ROW_LOCKS = ON, ALLOW_PAGE_LOCKS = ON) ON [PRIMARY]
GO
SET ANSI_PADDING ON
GO
/****** Object:  Index [JobMetrics]    Script Date: 17/10/2018 15:06:18 ******/
CREATE NONCLUSTERED INDEX [JobMetrics] ON [dbo].[Results]
(
    [JobId] ASC,
    [Source] ASC
)WITH (PAD_INDEX = OFF, STATISTICS_NORECOMPUTE = OFF, SORT_IN_TEMPDB = OFF, DROP_EXISTING = OFF, ONLINE = OFF, ALLOW_ROW_LOCKS = ON, ALLOW_PAGE_LOCKS = ON) ON [PRIMARY]
GO
SET ANSI_PADDING ON
GO
/****** Object:  Index [KEY_CAMPAIGN]    Script Date: 17/10/2018 15:06:18 ******/
CREATE NONCLUSTERED INDEX [KEY_CAMPAIGN] ON [dbo].[Results]
(
    [ResumeDownloadedDate] ASC,
    [ResumeDownloadStatus] ASC,
    [KeywordCampaignId] ASC,
    [Source] ASC
)WITH (PAD_INDEX = OFF, STATISTICS_NORECOMPUTE = OFF, SORT_IN_TEMPDB = OFF, DROP_EXISTING = OFF, ONLINE = OFF, ALLOW_ROW_LOCKS = ON, ALLOW_PAGE_LOCKS = ON) ON [PRIMARY]
GO
/****** Object:  Index [MISSING_CREATEDATE]    Script Date: 17/10/2018 15:06:18 ******/
CREATE NONCLUSTERED INDEX [MISSING_CREATEDATE] ON [dbo].[Results]
(
    [CreateDate] ASC
)
INCLUDE (   [Id]) WITH (PAD_INDEX = OFF, STATISTICS_NORECOMPUTE = OFF, SORT_IN_TEMPDB = OFF, DROP_EXISTING = OFF, ONLINE = OFF, ALLOW_ROW_LOCKS = ON, ALLOW_PAGE_LOCKS = ON) ON [PRIMARY]
GO
/****** Object:  Index [MISSING_MOVERSPROB]    Script Date: 17/10/2018 15:06:18 ******/
CREATE NONCLUSTERED INDEX [MISSING_MOVERSPROB] ON [dbo].[Results]
(
    [MoversProbability] ASC
)
INCLUDE (   [Id]) WITH (PAD_INDEX = OFF, STATISTICS_NORECOMPUTE = OFF, SORT_IN_TEMPDB = OFF, DROP_EXISTING = OFF, ONLINE = OFF, ALLOW_ROW_LOCKS = ON, ALLOW_PAGE_LOCKS = ON) ON [PRIMARY]
GO
/****** Object:  Index [MISSING_SORTORDER]    Script Date: 17/10/2018 15:06:18 ******/
CREATE NONCLUSTERED INDEX [MISSING_SORTORDER] ON [dbo].[Results]
(
    [SortOrder] ASC
)
INCLUDE (   [Id]) WITH (PAD_INDEX = OFF, STATISTICS_NORECOMPUTE = OFF, SORT_IN_TEMPDB = OFF, DROP_EXISTING = OFF, ONLINE = OFF, ALLOW_ROW_LOCKS = ON, ALLOW_PAGE_LOCKS = ON) ON [PRIMARY]
GO
SET ANSI_PADDING ON
GO
/****** Object:  Index [Proto_Resume_Downloa]    Script Date: 17/10/2018 15:06:18 ******/
CREATE NONCLUSTERED INDEX [Proto_Resume_Downloa] ON [dbo].[Results]
(
    [JobId] ASC,
    [ResumeDownloadedDate] ASC,
    [ResumeDownloadStatus] ASC,
    [Location] ASC,
    [Source] ASC
)WITH (PAD_INDEX = OFF, STATISTICS_NORECOMPUTE = OFF, SORT_IN_TEMPDB = OFF, DROP_EXISTING = OFF, ONLINE = OFF, ALLOW_ROW_LOCKS = ON, ALLOW_PAGE_LOCKS = ON) ON [PRIMARY]
GO
SET ANSI_PADDING ON
GO
/****** Object:  Index [Result_Email]    Script Date: 17/10/2018 15:06:18 ******/
CREATE NONCLUSTERED INDEX [Result_Email] ON [dbo].[Results]
(
    [Email] ASC
)WITH (PAD_INDEX = OFF, STATISTICS_NORECOMPUTE = OFF, SORT_IN_TEMPDB = OFF, DROP_EXISTING = OFF, ONLINE = OFF, ALLOW_ROW_LOCKS = ON, ALLOW_PAGE_LOCKS = ON) ON [PRIMARY]
GO
SET ANSI_PADDING ON
GO
/****** Object:  Index [Result_Email_Send]    Script Date: 17/10/2018 15:06:18 ******/
CREATE NONCLUSTERED INDEX [Result_Email_Send] ON [dbo].[Results]
(
    [EmailSentDate] ASC
)
INCLUDE (   [Id],
    [JobId],
    [AryaCandidateId],
    [Email],
    [IsEmailSubscribe],
    [EmailSent],
    [EmailStatus]) WITH (PAD_INDEX = OFF, STATISTICS_NORECOMPUTE = OFF, SORT_IN_TEMPDB = OFF, DROP_EXISTING = OFF, ONLINE = OFF, ALLOW_ROW_LOCKS = ON, ALLOW_PAGE_LOCKS = ON) ON [PRIMARY]
GO
SET ANSI_PADDING ON
GO
/****** Object:  Index [Results_JobId_ACI_Email]    Script Date: 17/10/2018 15:06:18 ******/
CREATE NONCLUSTERED INDEX [Results_JobId_ACI_Email] ON [dbo].[Results]
(
    [JobId] ASC
)
INCLUDE (   [Id],
    [AryaCandidateId],
    [Email]) WITH (PAD_INDEX = OFF, STATISTICS_NORECOMPUTE = OFF, SORT_IN_TEMPDB = OFF, DROP_EXISTING = OFF, ONLINE = OFF, ALLOW_ROW_LOCKS = ON, ALLOW_PAGE_LOCKS = ON) ON [PRIMARY]
GO
SET ANSI_PADDING ON
GO
/****** Object:  Index [RESULTS_JOBID_ALL]    Script Date: 17/10/2018 15:06:18 ******/
CREATE NONCLUSTERED INDEX [RESULTS_JOBID_ALL] ON [dbo].[Results]
(
    [JobId] ASC
)
INCLUDE (   [Id],
    [AryaCandidateId],
    [CandidateScore],
    [FirstName],
    [LastName],
    [Telephone],
    [Email],
    [AddressLine1],
    [Location],
    [Postcode],
    [Resume],
    [CurrentJob],
    [CurrentCompany],
    [Skills],
    [Experience],
    [Education],
    [AryaUpdateDate],
    [Industry],
    [Source],
    [LinkedIn],
    [Facebook],
    [Twitter],
    [MoversLabel],
    [MoversProbability],
    [SortOrder],
    [CreateDate],
    [ResumeId],
    [IsEmailSubscribe],
    [EmailSent],
    [EmailSentDate],
    [EmailStatus],
    [Registered],
    [HasVoyagerData],
    [Action],
    [Engaged],
    [FormattedCV],
    [CV],
    [DerivedSource],
    [VoyCode],
    [IsEmailEngaged],
    [IsSMSEngaged],
    [KeywordCampaignId]) WITH (PAD_INDEX = OFF, STATISTICS_NORECOMPUTE = OFF, SORT_IN_TEMPDB = OFF, DROP_EXISTING = OFF, ONLINE = OFF, ALLOW_ROW_LOCKS = ON, ALLOW_PAGE_LOCKS = ON) ON [PRIMARY]
GO
SET ANSI_PADDING ON
GO
/****** Object:  Index [ResultsGetResultsbyConsultantId]    Script Date: 17/10/2018 15:06:18 ******/
CREATE NONCLUSTERED INDEX [ResultsGetResultsbyConsultantId] ON [dbo].[Results]
(
    [JobId] ASC
)
INCLUDE (   [Id],
    [AryaCandidateId],
    [CandidateScore],
    [FirstName],
    [LastName],
    [Telephone],
    [Email],
    [AddressLine1],
    [Location],
    [Postcode],
    [Resume],
    [CurrentJob],
    [CurrentCompany],
    [Skills],
    [Experience],
    [Education],
    [AryaUpdateDate],
    [Industry],
    [Source],
    [LinkedIn],
    [Facebook],
    [Twitter],
    [MoversLabel],
    [MoversProbability],
    [DOB],
    [SortOrder],
    [ResumeDownloaded],
    [ResumeDownloadedDate],
    [ResumeDownloadStatus],
    [CreateDate],
    [ResumeId],
    [IsEmailSubscribe],
    [EmailSent],
    [EmailSentDate],
    [EmailStatus],
    [Action],
    [Engaged],
    [SentToArya],
    [IgnoreEmailSent],
    [IgnoreEmailSentDate],
    [FormattedCV],
    [CV],
    [DerivedSource],
    [IsEmailEngaged],
    [IsSMSEngaged]) WITH (PAD_INDEX = OFF, STATISTICS_NORECOMPUTE = OFF, SORT_IN_TEMPDB = OFF, DROP_EXISTING = OFF, ONLINE = OFF, ALLOW_ROW_LOCKS = ON, ALLOW_PAGE_LOCKS = ON) ON [PRIMARY]
GO
SET ANSI_PADDING ON
GO
/****** Object:  Index [Stats_Results_JOB_ACI_ACTION_ENGAGED]    Script Date: 17/10/2018 15:06:18 ******/
CREATE NONCLUSTERED INDEX [Stats_Results_JOB_ACI_ACTION_ENGAGED] ON [dbo].[Results]
(
    [JobId] ASC
)
INCLUDE (   [AryaCandidateId],
    [Action],
    [Engaged]) WITH (PAD_INDEX = OFF, STATISTICS_NORECOMPUTE = OFF, SORT_IN_TEMPDB = OFF, DROP_EXISTING = OFF, ONLINE = OFF, ALLOW_ROW_LOCKS = ON, ALLOW_PAGE_LOCKS = ON) ON [PRIMARY]
GO
/****** Object:  Index [Stats_Results_JobId_ACI]    Script Date: 17/10/2018 15:06:18 ******/
CREATE NONCLUSTERED INDEX [Stats_Results_JobId_ACI] ON [dbo].[Results]
(
    [JobId] ASC
)
INCLUDE (   [AryaCandidateId]) WITH (PAD_INDEX = OFF, STATISTICS_NORECOMPUTE = OFF, SORT_IN_TEMPDB = OFF, DROP_EXISTING = OFF, ONLINE = OFF, ALLOW_ROW_LOCKS = ON, ALLOW_PAGE_LOCKS = ON) ON [PRIMARY]
GO
SET ANSI_PADDING ON
GO
/****** Object:  Index [Stats_Results_JobId_ACI_Action_Engaged]    Script Date: 17/10/2018 15:06:18 ******/
CREATE NONCLUSTERED INDEX [Stats_Results_JobId_ACI_Action_Engaged] ON [dbo].[Results]
(
    [JobId] ASC
)
INCLUDE (   [AryaCandidateId],
    [Action],
    [Engaged]) WITH (PAD_INDEX = OFF, STATISTICS_NORECOMPUTE = OFF, SORT_IN_TEMPDB = OFF, DROP_EXISTING = OFF, ONLINE = OFF, ALLOW_ROW_LOCKS = ON, ALLOW_PAGE_LOCKS = ON) ON [PRIMARY]
GO
SET ANSI_PADDING ON
GO
/****** Object:  Index [Stats_Results_JobId_ACI_DERIVED]    Script Date: 17/10/2018 15:06:18 ******/
CREATE NONCLUSTERED INDEX [Stats_Results_JobId_ACI_DERIVED] ON [dbo].[Results]
(
    [JobId] ASC
)
INCLUDE (   [AryaCandidateId],
    [DerivedSource]) WITH (PAD_INDEX = OFF, STATISTICS_NORECOMPUTE = OFF, SORT_IN_TEMPDB = OFF, DROP_EXISTING = OFF, ONLINE = OFF, ALLOW_ROW_LOCKS = ON, ALLOW_PAGE_LOCKS = ON) ON [PRIMARY]
GO
SET ANSI_PADDING ON
GO
/****** Object:  Index [Stats_Results_JobId_SOURCE_ACI]    Script Date: 17/10/2018 15:06:18 ******/
CREATE NONCLUSTERED INDEX [Stats_Results_JobId_SOURCE_ACI] ON [dbo].[Results]
(
    [JobId] ASC,
    [Source] ASC
)
INCLUDE (   [AryaCandidateId]) WITH (PAD_INDEX = OFF, STATISTICS_NORECOMPUTE = OFF, SORT_IN_TEMPDB = OFF, DROP_EXISTING = OFF, ONLINE = OFF, ALLOW_ROW_LOCKS = ON, ALLOW_PAGE_LOCKS = ON) ON [PRIMARY]
GO
SET ANSI_PADDING ON
GO
/****** Object:  Index [Stats_Results_JobId_Source_ACI_V2]    Script Date: 17/10/2018 15:06:18 ******/
CREATE NONCLUSTERED INDEX [Stats_Results_JobId_Source_ACI_V2] ON [dbo].[Results]
(
    [JobId] ASC,
    [Source] ASC
)
INCLUDE (   [AryaCandidateId]) WITH (PAD_INDEX = OFF, STATISTICS_NORECOMPUTE = OFF, SORT_IN_TEMPDB = OFF, DROP_EXISTING = OFF, ONLINE = OFF, ALLOW_ROW_LOCKS = ON, ALLOW_PAGE_LOCKS = ON) ON [PRIMARY]
GO
ALTER TABLE [dbo].[Results] ADD  CONSTRAINT [DF_Results_CreateDate]  DEFAULT (getdate()) FOR [CreateDate]
GO

【问题讨论】：

标签： sql sql-server database common-table-expression sqlperformance

【解决方案1】：

我有一些建议可以减少执行时间：

如果主记录的邮件为空，则不需要运行子查询：

所以用这个语句代替：

AND NOT EXISTS (        
            SELECT u.Id FROM Unsubscribe u
            WHERE (u.EmailAddress = R.Email OR (u.EmailAddress IS NULL AND R.Email IS NULL)) 
        )

使用下面的语句：

 AND (NOT EXISTS (        
            SELECT u.Id FROM Unsubscribe u
            WHERE u.EmailAddress = R.Email ) 
        ) or  R.Email IS NULL) -- you dont need to check is it is null

我建议您尽可能减少或符号，请尝试使用联合而不是 OR。您可以在以下链接中找到一些示例：

SQL Performance UNION vs OR

据我了解，您可以使用 JOBID 过滤 SMTP_Production 记录，如果可以的话：

而不是这个声明

 AND NOT EXISTS (
            SELECT SMTP.Id FROM SMTP_Production SMTP
            WHERE SMTP.EmailStatus = 'PICKUP' AND SMTP.CandidateId = R.CandidateId -- can we add SMTP.JobId = R.JobId
        )

你可以在下面使用

 AND NOT EXISTS (
            SELECT SMTP.Id FROM SMTP_Production SMTP
            WHERE SMTP.EmailStatus = 'PICKUP' AND SMTP.CandidateId = R.CandidateId and SMTP.JobId = R.JobId 
        )

查询的最终版本可能是这样的：

WITH CTE AS 
(
    SELECT R.Id AS ResultId,
        r.JobId,
        r.CandidateId,
        R.Email,
        CAST(0 AS BIT) AS EmailSent,
        NULL AS EmailSentDate,
        'PICKUP' AS EmailStatus,
        GETDATE() AS CreateDate,
        C.Id AS UserId,
        C.Email AS UserEmail,
        NULL AS Subject
    FROM RESULTS R
    INNER JOIN JOB J ON R.JobId = J.Id
    INNER JOIN Consultant C ON J.UserId = C.Id
    WHERE 
        J.DCApproved = 1
        AND (J.Closed <> 1)
        AND (R.Email <> '' OR R.Email IS NOT NULL)
        AND (R.EmailSent <> 1)
        AND R.EmailSentDate IS NULL -- email has not been sent
        AND (R.EmailStatus = '' OR R.EmailStatus IS NULL)
        AND (R.IsEmailSubscribe <> 'False')
        -- not already been emailed for this job
        AND NOT EXISTS (
            SELECT SMTP.Email
            FROM SMTP_Production SMTP
            WHERE SMTP.JobId = R.JobId AND SMTP.CandidateId = R.CandidateId
        )
        -- not unsubscribed
          AND ((NOT EXISTS (        
            SELECT u.Id FROM Unsubscribe u
            WHERE u.EmailAddress = R.Email ) 
        ) or  R.Email IS NULL) )
         AND NOT EXISTS (
            SELECT SMTP.Id FROM SMTP_Production SMTP
            WHERE SMTP.EmailStatus = 'PICKUP' AND SMTP.CandidateId = R.CandidateId and SMTP.JobId = R.JobId 
        ) 
        AND C.Id NOT IN (
            -- LIST OF IDS
        )
        AND J.Id NOT IN (
            -- LIST OF IDS
        )
        AND J.ClientId NOT IN 
        (
            -- LIST OF IDS
        )
)

SELECT 
    CTE.ResultId,
    CTE.JobId,
    CTE.CandidateId,
    CTE.Email,
    CTE.EmailSent,
    CTE.EmailSentDate,
    CTE.EmailStatus,
    CTE.CreateDate,
    CTE.UserId,
    CTE.UserEmail,
    NULL
FROM CTE
  INNER JOIN 
    (
        SELECT *, row_number() over(partition by CTE.Email, CTE.CandidateId order by CTE.EmailSentDate desc) as rn
        FROM CTE

    ) DCTE ON CTE.ResultId = DCTE.ResultId AND DCTE.rn = 1

【讨论】：

不看执行计划，我喜欢 3 - 可以为完全不同的计划排在首位。2 应该是无关紧要的（查询优化器 - 想知道是否没有优化）。 1 可能也不错。
这是真的，最好的方法是利用联合而不是“或”我将其添加到我的答案中。
谢谢，我会尝试这些并报告，再次感谢
很遗憾，由于业务规则，我无法执行第 3 条建议，但是添加它确实会产生不错的影响，我执行了更改 1，它有一个小的改进，再次感谢
与计算列建立关系总是很慢。您是否可以考虑将带有 row_number 列的 CTE 表写入临时表并在查询中使用此临时表？