first, I know that the situation in my client does not follow the best practice(
https://blogs.msdn.microsoft.com/spblog/2012/03/13/security-infrastructure-related-performance-problems/
): they have more then 20,000 security scopes in a single document library. And a not so well developed custom library view page takes long time to open(almost 1 minute). what follows is a long running T-SQL query I caught with profiler:
exec sp_executesql N'DECLARE @DocParentIdForRF uniqueidentifier SELECT TOP 1 @DocParentIdForRF = Docs.Id FROM Docs WHERE Docs.SiteId = @SITEID AND Docs.DirName = @FDN AND Docs.LeafName = @FLN; SELECT ScopeId, Acl, AnonymousPermMask FROM Perms WITH (INDEX=Perms_Url) WHERE SiteId=@SITEID AND DelTransId = 0x AND ScopeId IN (SELECT tp_ScopeId FROM Lists WITH (NOLOCK) WHERE tp_WebId=@L9 AND tp_ID = @L2 UNION SELECT t1.ScopeId FROM UserData INNER JOIN Docs AS t1 WITH(NOLOCK) ON (UserData.[tp_ID]=t1.[DoclibRowId]) AND (UserData.[tp_RowOrdinal] = 0) AND (t1.SiteId=UserData.tp_SiteId) AND (t1.SiteId = @SITEID) AND (t1.ParentId = UserData.tp_ParentId) AND (t1.Id = UserData.tp_DocId) AND (UserData.tp_ListId = @L2) LEFT OUTER LOOP JOIN AllUserData AS t2 WITH(NOLOCK,INDEX=AllUserData_PK) ON (UserData.[tp_Editor]=t2.[tp_ID]) AND (UserData.[tp_RowOrdinal] = 0) AND (t2.[tp_RowOrdinal] = 0) AND ( (t2.tp_Level = 1) ) AND (t2.[tp_IsCurrentVersion] = CONVERT(bit,1) ) AND (t2.[tp_CalculatedVersion] = 0 ) AND (t2.[tp_DeleteTransactionId] = 0x ) AND (t2.tp_ListId = @L3) AND (UserData.tp_ListId = @L2) LEFT OUTER LOOP JOIN AllUserData AS t3 WITH(NOLOCK,INDEX=AllUserData_PK) ON (UserData.[tp_CheckoutUserId]=t3.[tp_ID]) AND (UserData.[tp_RowOrdinal] = 0) AND (t3.[tp_RowOrdinal] = 0) AND ( (t3.tp_Level = 1) ) AND (t3.[tp_IsCurrentVersion] = CONVERT(bit,1) ) AND (t3.[tp_CalculatedVersion] = 0 ) AND (t3.[tp_DeleteTransactionId] = 0x ) AND (t3.tp_ListId = @L3) AND (UserData.tp_ListId = @L2) LEFT OUTER LOOP JOIN AllUserData AS t4 WITH(NOLOCK,INDEX=AllUserData_PK) ON (UserData.[int1]=t4.[tp_ID]) AND (UserData.[tp_RowOrdinal] = 0) AND (t4.[tp_RowOrdinal] = 0) AND ( (t4.tp_Level = 1) ) AND (t4.[tp_IsCurrentVersion] = CONVERT(bit,1) ) AND (t4.[tp_CalculatedVersion] = 0 ) AND (t4.[tp_DeleteTransactionId] = 0x ) AND (t4.tp_ListId = @L4) AND (UserData.tp_ListId = @L2) LEFT OUTER LOOP JOIN AllUserData AS t6 WITH(NOLOCK,INDEX=AllUserData_PK) ON (UserData.[int3]=t6.[tp_ID]) AND (UserData.[tp_RowOrdinal] = 0) AND (t6.[tp_RowOrdinal] = 0) AND ( (t6.tp_Level = 1) ) AND (t6.[tp_IsCurrentVersion] = CONVERT(bit,1) ) AND (t6.[tp_CalculatedVersion] = 0 ) AND (t6.[tp_DeleteTransactionId] = 0x ) AND (t6.tp_ListId = @L4) AND (UserData.tp_ListId = @L2) LEFT OUTER LOOP JOIN AllUserData AS t7 WITH(NOLOCK,INDEX=AllUserData_PK) ON (UserData.[int4]=t7.[tp_ID]) AND (UserData.[tp_RowOrdinal] = 0) AND (t7.[tp_RowOrdinal] = 0) AND ( (t7.tp_Level = 1) ) AND (t7.[tp_IsCurrentVersion] = CONVERT(bit,1) ) AND (t7.[tp_CalculatedVersion] = 0 ) AND (t7.[tp_DeleteTransactionId] = 0x ) AND (t7.tp_ListId = @L4) AND (UserData.tp_ListId = @L2) LEFT OUTER LOOP JOIN AllUserData AS t8 WITH(NOLOCK,INDEX=AllUserData_PK) ON (UserData.[int5]=t8.[tp_ID]) AND (UserData.[tp_RowOrdinal] = 0) AND (t8.[tp_RowOrdinal] = 0) AND ( (t8.tp_Level = 1) ) AND (t8.[tp_IsCurrentVersion] = CONVERT(bit,1) ) AND (t8.[tp_CalculatedVersion] = 0 ) AND (t8.[tp_DeleteTransactionId] = 0x ) AND (t8.tp_ListId = @L4) AND (UserData.tp_ListId = @L2) LEFT OUTER LOOP JOIN AllUserData AS t9 WITH(NOLOCK,INDEX=AllUserData_PK) ON (UserData.[int6]=t9.[tp_ID]) AND (UserData.[tp_RowOrdinal] = 0) AND (t9.[tp_RowOrdinal] = 0) AND ( (t9.tp_Level = 1) ) AND (t9.[tp_IsCurrentVersion] = CONVERT(bit,1) ) AND (t9.[tp_CalculatedVersion] = 0 ) AND (t9.[tp_DeleteTransactionId] = 0x ) AND (t9.tp_ListId = @L3) AND (UserData.tp_ListId = @L2) LEFT OUTER LOOP JOIN AllUserData AS t11 WITH(NOLOCK,INDEX=AllUserData_PK) ON (UserData.[tp_Author]=t11.[tp_ID]) AND (UserData.[tp_RowOrdinal] = 0) AND (t11.[tp_RowOrdinal] = 0) AND ( (t11.tp_Level = 1) ) AND (t11.[tp_IsCurrentVersion] = CONVERT(bit,1) ) AND (t11.[tp_CalculatedVersion] = 0 ) AND (t11.[tp_DeleteTransactionId] = 0x ) AND (t11.tp_ListId = @L3) AND (UserData.tp_ListId = @L2) LEFT OUTER LOOP JOIN AllUserData AS t12 WITH(NOLOCK,INDEX=AllUserData_PK) ON (t1.[LTCheckoutUserId]=t12.[tp_ID]) AND (t12.[tp_RowOrdinal] = 0) AND ( (t12.tp_Level = 1) ) AND (t12.[tp_IsCurrentVersion] = CONVERT(bit,1) ) AND (t12.[tp_CalculatedVersion] = 0 ) AND (t12.[tp_DeleteTransactionId] = 0x ) AND (t12.tp_ListId = @L3) WHERE ( (UserData.tp_Level = 1 OR UserData.tp_Level =255) AND ( UserData.tp_Level= 255 AND UserData.tp_CheckoutUserId = @IU OR ( UserData.tp_Level = 2 AND UserData.tp_DraftOwnerId IS NOT NULL OR UserData.tp_Level = 1 AND UserData.tp_DraftOwnerId IS NULL ) AND ( UserData.tp_CheckoutUserId IS NULL OR UserData.tp_CheckoutUserId <> @IU))) AND (UserData.tp_SiteId=@SITEID AND (UserData.tp_ParentId=@DocParentIdForRF)) AND (UserData.tp_RowOrdinal=0) AND (t1.SiteId=@SITEID AND (t1.ParentId=@DocParentIdForRF))) OPTION (MAXDOP 1)',N'@LFFP uniqueidentifier,@SITEID uniqueidentifier,@L2 uniqueidentifier,@L3 uniqueidentifier,@L4 uniqueidentifier,@FDN nvarchar(4000),@FLN nvarchar(4000),@IU int,@RequestGuid uniqueidentifier,@L9 uniqueidentifier',@LFFP='00000000-0000-0000-0000-000000000000',@SITEID='5F781AF7-ECAC-4610-9455-D31197DAEB1A',@L2='ECC5AFEB-D187-4EE8-A944-522AD7EE2E70',@L3='3A177C8F-4A48-470E-BE16-68EEE47B5080',@L4='B4049485-6A59-478D-A819-82EB99F1252F',@FDN=N'dc/kms/ProjectDoc',@FLN=N'人力资源管理',@IU=17,@RequestGuid='587989E5-D215-422D-A23D-F787AF1CFE5D',@L9='AF661FD8-3D5F-4D5E-9DE8-FBC1678176FE'
Although the duration in profiler for this query is around 600, it runs many times when the custom page opens.
And the Excecution Plan show that a cluster index seek operation on Perms table runs more than 20,000 times (the number of security scopes).
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And the execution time in query analyzer is more than 300:
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But, if I make some simple change to the SQL query I caught by simply remove theWITH (INDEX=Perms_Url) .The Execute plan will change, no operation will run more then 20,000 times and the execution time will be around 30, that is, 10 times faster.
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The question is, where is this complex query generated from SharePoint and can I control to remove the index hint as in my test?
The SharePoint buildversion is 14.0.6112.5000