Query is very very slow for processing 200000 plus records - sql

Question

I have 200,000 rows in Patient & Person table, and the query shown takes 30 secs to execute.
I have defined the primary key (and clustered index) in the Person table on PersonId and on PatientId in the Patient table. What else can I do here to improve performance of my procedure?
New to database development side. I know only basic SQL. Also not sure SQL Server can handle 200,000 rows quickly.
Whole dynamic Procedure you can see at https://github.com/Padayappa/SQLProblem/blob/master/Performance
Anyone faced handling huge rows like this? How do I improve performance here?
DECLARE #return_value int,
#unitRows bigint,
#unitPages int,
#TenantId int,
#unitItems int,
#page int
SET #TenantId = 1
SET #unitItems = 20
SET #page = 1
DECLARE #PatientSearch TABLE(
[PatientId] [bigint] NOT NULL,
[PatientIdentifier] [nvarchar](50) NULL,
[PersonNumber] [nvarchar](20) NULL,
[FirstName] [nvarchar](100) NOT NULL,
[LastName] [nvarchar](100) NOT NULL,
[ResFirstName] [nvarchar](100) NOT NULL,
[ResLastName] [nvarchar](100) NOT NULL,
[AddFirstName] [nvarchar](100) NOT NULL,
[AddLastName] [nvarchar](100) NOT NULL,
[Address] [nvarchar](255) NULL,
[City] [nvarchar](50) NULL,
[State] [nvarchar](50) NULL,
[ZipCode] [nvarchar](20) NULL,
[Country] [nvarchar](50) NULL,
[RowNumber] [bigint] NULL
)
INSERT INTO #PatientSearch SELECT PAT.PatientId
,PAT.PatientIdentifier
,PER.PersonNumber
,PER.FirstName
,PER.LastName
,RES_PER.FirstName AS ResFirstName
,RES_PER.LastName AS ResLastName
,ADD_PER.FirstName AS AddFirstName
,ADD_PER.LastName AS AddLastName
,PER.Address
,PER.City
,PER.State
,PER.ZipCode
,PER.Country
,ROW_NUMBER() OVER (ORDER BY PAT.PatientId DESC) AS RowNumber
FROM dbo.Patient AS PAT
INNER JOIN dbo.Person AS PER
ON PAT.PersonId = PER.PersonId
INNER JOIN dbo.Person AS RES_PER
ON PAT.ResponsiblePersonId = RES_PER.PersonId
INNER JOIN dbo.Person AS ADD_PER
ON PAT.AddedBy = ADD_PER.PersonId
INNER JOIN dbo.Booking AS B
ON PAT.PatientId = B.PatientId
WHERE PAT.TenantId = #TenantId AND B.CategoryId = #CategoryId
GROUP BY PAT.PatientId
,PAT.PatientIdentifier
,PER.PersonNumber
,PER.FirstName
,PER.LastName
,RES_PER.FirstName
,RES_PER.LastName
,ADD_PER.FirstName
,ADD_PER.LastName
,PER.Address
,PER.City
,PER.State
,PER.ZipCode
,PER.Country
;
SELECT #unitRows = ##ROWCOUNT
,#unitPages = (#unitRows / #unitItems) + 1;
SELECT *
FROM #PatientSearch AS IT
WHERE RowNumber BETWEEN (#page - 1) * #unitItems + 1 AND #unitItems * #page

Answer 1

Well, unless I am missing something (like duplicate rows?) you should be able to remove the GROUP BY
GROUP BY PAT.PatientId
,PAT.PatientIdentifier
,PER.PersonNumber
,PER.FirstName
,PER.LastName
,RES_PER.FirstName
,RES_PER.LastName
,ADD_PER.FirstName
,ADD_PER.LastName
,PER.Address
,PER.City
,PER.State
,PER.ZipCode
,PER.Country
as you are grouping by all fields in the select list, and you are partitioning by PAT.PatientId
Further to that, you should create index on the tables with the index containing columns that you join/filter on.
So for instance I would create an index on table Patient with columns (TenantId,PersonId,ResponsiblePersonId,AddedBy) with included columns (PatientId,PatientIdentifier)

Answer 2

Frankly speaking, 200,000 rows is nothing to SQL server. Please first remove logic redundancy, like you have primary key, why still group so many columns, and why you need to join same table (person) 3 times? After removing logic redundancy, you need to create some composite index/include index at least. Get the execution plan (CTRL+M) or (CTRL+M), to see what index you missed. If you need further help, please paste your table schema with few rows of sample data.