[PM-21031] Optimize GET Members endpoint performance (#5907)

* Add new feature flag for Members Get Endpoint Optimization

* Add a new version of OrganizationUser_ReadByOrganizationIdWithClaimedDomains that uses CTE for better performance

* Add stored procedure OrganizationUserUserDetails_ReadByOrganizationId_V2 for retrieving user details, group associations, and collection associations by organization ID.

* Add the sql migration script to add the new stored procedures

* Introduce GetManyDetailsByOrganizationAsync_vNext and GetManyByOrganizationWithClaimedDomainsAsync_vNext in IOrganizationUserRepository to enhance performance by reducing database round trips.

* Updated GetOrganizationUsersClaimedStatusQuery to use an optimized query when the feature flag is enabled

* Updated OrganizationUserUserDetailsQuery to use optimized queries when the feature flag is enabled

* Add integration tests for GetManyDetailsByOrganizationAsync_vNext

* Add integration tests for GetManyByOrganizationWithClaimedDomainsAsync_vNext to validate behavior with verified and unverified domains.

* Optimize performance by conditionally setting permissions only for Custom user types in OrganizationUserUserDetailsQuery.

* Create UserEmailDomainView to extract email domains from users' email addresses

* Create stored procedure Organization_ReadByClaimedUserEmailDomain_V2 that uses UserEmailDomainView to fetch Email domains

* Add GetByVerifiedUserEmailDomainAsync_vNext method to IOrganizationRepository and its implementations

* Refactor OrganizationUser_ReadByOrganizationIdWithClaimedDomains_V2 stored procedure to use UserEmailDomainView for email domain extraction, improving query efficiency and clarity.

* Enhance IOrganizationUserRepository with detailed documentation for GetManyDetailsByOrganizationAsync method, clarifying its purpose and performance optimizations. Added remarks for better understanding of its functionality.

* Fix missing newline at the end of Organization_ReadByClaimedUserEmailDomain_V2.sql to adhere to coding standards.

* Update the database migration script to include UserEmailDomainView

* Bumped the date on the migration script

* Remove GetByVerifiedUserEmailDomainAsync_vNext method and its stored procedure.

* Refactor UserEmailDomainView index creation to check for existence before creation

* Update OrganizationUser_ReadByOrganizationIdWithClaimedDomains_V2 to use CTE and add indexes

* Remove creation of unique clustered index from UserEmailDomainView and related migration script adjustments

* Update indexes and sproc

* Fix index name when checking if it already exists

* Bump up date on migration script

src/Sql/dbo/Stored Procedures/OrganizationUserUserDetails_ReadByOrganizationId_V2.sql

@@ -0,0 +1,31 @@
+CREATE PROCEDURE [dbo].[OrganizationUserUserDetails_ReadByOrganizationId_V2]
+    @OrganizationId UNIQUEIDENTIFIER,
+    @IncludeGroups BIT = 0,
+    @IncludeCollections BIT = 0
+AS
+BEGIN
+    SET NOCOUNT ON
+
+    -- Result Set 1: User Details (always returned)
+    SELECT * 
+    FROM [dbo].[OrganizationUserUserDetailsView] 
+    WHERE OrganizationId = @OrganizationId
+
+    -- Result Set 2: Group associations (if requested)
+    IF @IncludeGroups = 1
+    BEGIN
+        SELECT gu.*
+        FROM [dbo].[GroupUser] gu
+        INNER JOIN [dbo].[OrganizationUser] ou ON gu.OrganizationUserId = ou.Id
+        WHERE ou.OrganizationId = @OrganizationId
+    END
+
+    -- Result Set 3: Collection associations (if requested)  
+    IF @IncludeCollections = 1
+    BEGIN
+        SELECT cu.*
+        FROM [dbo].[CollectionUser] cu
+        INNER JOIN [dbo].[OrganizationUser] ou ON cu.OrganizationUserId = ou.Id
+        WHERE ou.OrganizationId = @OrganizationId
+    END
+END

src/Sql/dbo/Stored Procedures/OrganizationUser_ReadByOrganizationIdWithClaimedDomains_V2.sql

@@ -0,0 +1,27 @@
+CREATE PROCEDURE [dbo].[OrganizationUser_ReadByOrganizationIdWithClaimedDomains_V2]
+    @OrganizationId UNIQUEIDENTIFIER
+AS
+BEGIN
+    SET NOCOUNT ON;
+
+    WITH OrgUsers AS (
+        SELECT *
+        FROM [dbo].[OrganizationUserView]
+        WHERE [OrganizationId] = @OrganizationId
+    ),
+    UserDomains AS (
+        SELECT U.[Id], U.[EmailDomain]
+        FROM [dbo].[UserEmailDomainView] U
+        WHERE EXISTS (
+            SELECT 1
+            FROM [dbo].[OrganizationDomainView] OD 
+            WHERE OD.[OrganizationId] = @OrganizationId
+            AND OD.[VerifiedDate] IS NOT NULL
+            AND OD.[DomainName] = U.[EmailDomain]
+        )
+    )
+    SELECT OU.*
+    FROM OrgUsers OU
+    JOIN UserDomains UD ON OU.[UserId] = UD.[Id]
+    OPTION (RECOMPILE);
+END

src/Sql/dbo/Tables/OrganizationDomain.sql

@@ -25,5 +25,11 @@ GO
 
 CREATE NONCLUSTERED INDEX [IX_OrganizationDomain_DomainNameVerifiedDateOrganizationId]
     ON [dbo].[OrganizationDomain] ([DomainName],[VerifiedDate])
-    INCLUDE ([OrganizationId])
+    INCLUDE ([OrganizationId]);
+GO
+
+CREATE NONCLUSTERED INDEX [IX_OrganizationDomain_OrganizationId_VerifiedDate]
+    ON [dbo].[OrganizationDomain] ([OrganizationId], [VerifiedDate])
+    INCLUDE ([DomainName])
+    WHERE [VerifiedDate] IS NOT NULL;
 GO

src/Sql/dbo/Tables/OrganizationUser.sql

@@ -27,3 +27,10 @@ GO
 CREATE NONCLUSTERED INDEX [IX_OrganizationUser_OrganizationId]
     ON [dbo].[OrganizationUser]([OrganizationId] ASC);
 
+GO
+
+CREATE NONCLUSTERED INDEX [IX_OrganizationUser_OrganizationId_UserId]
+    ON [dbo].[OrganizationUser] ([OrganizationId], [UserId])
+    INCLUDE ([Email], [Status], [Type], [ExternalId], [CreationDate], 
+        [RevisionDate], [Permissions], [ResetPasswordKey], [AccessSecretsManager]);
+GO

src/Sql/dbo/Tables/User.sql

@@ -54,3 +54,7 @@ GO
 CREATE NONCLUSTERED INDEX [IX_User_Premium_PremiumExpirationDate_RenewalReminderDate]
     ON [dbo].[User]([Premium] ASC, [PremiumExpirationDate] ASC, [RenewalReminderDate] ASC);
 
+GO
+CREATE NONCLUSTERED INDEX [IX_User_Id_EmailDomain]
+    ON [dbo].[User]([Id] ASC, [Email] ASC);
+

src/Sql/dbo/Views/UserEmailDomainView.sql

@@ -0,0 +1,10 @@
+CREATE VIEW [dbo].[UserEmailDomainView]
+AS
+SELECT 
+    Id,
+    Email,
+    SUBSTRING(Email, CHARINDEX('@', Email) + 1, LEN(Email)) AS EmailDomain
+FROM dbo.[User]
+WHERE Email IS NOT NULL 
+    AND CHARINDEX('@', Email) > 0
+GO