Very large document libraries - very strange SQL

If you ever come across the following SQL statement you need to take a critical look at various web parts other SharePoint related code recently deployed at your site.

SELECT TOP 2147483648 t2.[tp_Created] AS c3c8,t1.[Type] AS c0,t3.[tp_ID] AS c10c5,UserData.[nvarchar10],t1.[Id] AS c15,t4.[tp_Created] AS c17c8,UserData.[tp_ItemOrder],UserData.[tp_ModerationStatus],UserData.[nvarchar1],UserData.[nvarchar6],UserData.[bit2],UserData.[tp_Created],t1.[CheckinComment] AS c23,UserData.[tp_WorkflowInstanceID],t2.[nvarchar4] AS c3c6,t3.[tp_Created] AS c10c8,UserData.[ntext1],t4.[nvarchar4] AS c17c6,t1.[DirName] AS c18,UserData.[tp_ID],t1.[ProgId] AS c13,UserData.[nvarchar5],UserData.[bit1],t1.[Size] AS c21,UserData.[tp_GUID],t1.[TimeCreated] AS c1,UserData.[tp_Editor],UserData.[tp_Author],t2.[nvarchar1] AS c3c4,t3.[nvarchar4] AS c10c6,UserData.[nvarchar2],UserData.[nvarchar7],UserData.[nvarchar13],UserData.[tp_ContentType],t1.[LTCheckoutUserId] AS c20,t1.[TimeLastModified] AS c9,CASE WHEN DATALENGTH(t1.DirName) = 0 THEN t1.LeafName WHEN DATALENGTH(t1.LeafName) = 0 THEN t1.DirName ELSE t1.DirName + N'/' + t1.LeafName END AS c11,t1.[ScopeId] AS c16,UserData.[tp_ContentTypeId],UserData.[sql_variant1],t4.[nvarchar1] AS c17c4,UserData.[tp_WorkflowVersion],t1.[ParentVersionString] AS c24,UserData.[nvarchar4],UserData.[tp_CheckoutUserId],UserData.[tp_Version],UserData.[nvarchar9],t5.[nvarchar1] AS c4,UserData.[tp_IsCurrentVersion],t2.[nvarchar5] AS c3c7,t3.[nvarchar1] AS c10c4,UserData.[tp_HasCopyDestinations],UserData.[tp_Level],UserData.[nvarchar12],t1.[MetaInfo] AS c14,t4.[nvarchar5] AS c17c7,t1.[Size] AS c19,t1.[LeafName] AS c2,UserData.[tp_Modified],UserData.[nvarchar3],UserData.[nvarchar8],UserData.[tp_UIVersion],t2.[tp_ID] AS c3c5,t3.[nvarchar5] AS c10c7,UserData.[tp_CopySource],UserData.[nvarchar11],UserData.[tp_InstanceID],t1.[IsCheckoutToLocal] AS c12,t4.[tp_ID] AS c17c5,UserData.[tp_UIVersionString],t1.[ParentLeafName] AS c25 FROM UserData INNER MERGE JOIN Docs AS t1 WITH(NOLOCK) ON ( 1 = 1 AND UserData.[tp_RowOrdinal] = 0 AND t1.SiteId = UserData.tp_SiteId AND t1.SiteId = @L2 AND t1.DirName = UserData.tp_DirName AND t1.LeafName = UserData.tp_LeafName AND t1.Level = UserData.tp_Level AND (UserData.tp_Level = 255 AND t1.LTCheckoutUserId =@IU OR (UserData.tp_Level = 1 AND (UserData.tp_DraftOwnerId IS NULL OR (UserData.tp_DraftOwnerId <>@IU AND 1=0 )) OR UserData.tp_Level = 2 AND (UserData.tp_DraftOwnerId = @IU OR 1=1 )) AND (t1.LTCheckoutUserId IS NULL OR t1.LTCheckoutUserId <> @IU )) AND (1 = 1)) LEFT OUTER 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_IsCurrent = 1) ) AND t2.[tp_CalculatedVersion] = 0 AND t2.[tp_DeleteTransactionId] = 0x AND t2.tp_ListId = @L3 AND UserData.tp_ListId = @L4) LEFT OUTER 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_IsCurrent = 1) ) AND t3.[tp_CalculatedVersion] = 0 AND t3.[tp_DeleteTransactionId] = 0x AND t3.tp_ListId = @L3 AND UserData.tp_ListId = @L4) LEFT OUTER JOIN AllUserData AS t4 WITH(NOLOCK, INDEX=AllUserData_PK) ON (UserData.[tp_Author]=t4.[tp_ID] AND UserData.[tp_RowOrdinal] = 0 AND t4.[tp_RowOrdinal] = 0 AND ( (t4.tp_IsCurrent = 1) ) AND t4.[tp_CalculatedVersion] = 0 AND t4.[tp_DeleteTransactionId] = 0x AND t4.tp_ListId = @L3 AND UserData.tp_ListId = @L4) LEFT OUTER JOIN AllUserData AS t5 WITH(NOLOCK, INDEX=AllUserData_PK) ON (t1.[LTCheckoutUserId]=t5.[tp_ID] AND t5.[tp_RowOrdinal] = 0 AND ( (t5.tp_IsCurrent = 1) ) AND t5.[tp_CalculatedVersion] = 0 AND t5.[tp_DeleteTransactionId] = 0x AND t5.tp_ListId = @L3) WHERE (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=@L2 AND (UserData.tp_DirName=@DN OR UserData.tp_DirName LIKE @DNEL+N'/%') AND UserData.tp_RowOrdinal=0 AND (t1.SiteId=@L2 AND (t1.DirName=@DN OR t1.DirName LIKE @DNEL+N'/%') AND t1.Type=0) ORDER BY t1.[Type] Desc,UserData.[tp_ID] Asc OPTION (FORCE ORDER)

This blog describes a similar issue, as well as this blog. Using
targetList.Items[...]
can cause this issue. Use
targetList.GetItemByUniqueId(...) or
targetList.GetItemById(...)
instead.

Also - might be related to this issue reported by Microsoft. A hotfix exists!