SELECT ...
FROM tbPrecalc ...
UNION ALL
SELECT ...
FROM tbPrecalc ...

-- Всего 3 UNION ALL

BEGIN TRAN

CREATE TABLE tbPrecalcTmp
-- заполнить  tbPrecalcTmp

DROP TABLE tbPrecalc

sp_rename 'tbPrecalcTmp', 'tbPrecalc'

COMMIT TRAN

Microsoft SQL Server 2017 (RTM-CU16) (KB4508218) - 14.0.3223.3 (X64) 
	Jul 12 2019 17:43:08 
	Copyright (C) 2017 Microsoft Corporation
	Developer Edition (64-bit) on Windows Server 2019 Datacenter 10.0 <X64> (Build 17763: ) (Hypervisor)

ALTER PROCEDURE  DataPrecalculate
(    
    @ids PkList readonly   -- (list of int)
) 
AS
BEGIN
...
BEGIN TRAN
declare @entityList PkList  (

        if exists(select 1 from @ids)
        begin
            insert into @entityList(Id)
            select d.Id
            from tbData d
                inner join @ids i on d.Id = i.Id
        end
        else begin
            insert into @entityList(Id)
            select Id
            from tbData d
        end
     
    delete r
        from tbPrecalc r
        inner join @entityList c on r.EntityId = c.Id

insert into tbPrecalc
... from tbData ...

insert into tbPrecalc
...

;with ...
insert into tbPrecalc

COMMIT TRAN
...
END

CREATE PROCEDURE tbPrecalc_Get
(
    @entitytId int,
    ...
) AS
BEGIN
    ;with x as ...,
     xx as
    (
        select ...
        from tbPrecalc ...

        union all
        select ...
        from tbPrecalc ...​

        union all
        select ...
        from tbPrecalc ...

        union all
        select ...
        from tbPrecalc ...
    )
    insert into #result ...
 
END

select name, is_read_committed_snapshot_on from sys.databases where name = 'DEV'

delete r
        from tbPrecalc r
        inner join @entityList c on r.EntityId = c.Id

select ...
from tbPrecalc p ...
where p.EntityId = @entityId
            and (p.ClientId in (select Id from #clients_tmp) or p.ClientId is null)
union all ...

ALTER PROCEDURE  DataPrecalculateAll 
AS
BEGIN
BEGIN TRY

-- реализация синглтона с помощью sys.sp_getapplock

    drop table if exists tbPrecalc_EmptyPhantom
    create table tbPrecalc_EmptyPhantom

    ALTER INDEX ALL ON tbPrecalc_temp DISABLE
    truncate table tbPrecalc_temp  -- она и так должна быть пустой, но на всякий случай

-- заполнение tbPrecalc_temp
-- включение всех индексов на tbPrecalc_temp

BEGIN TRAN
    alter table tbPrecalc switch to tbPrecalc_EmptyPhantom;
    alter table tbPrecalc_temp switch to tbPrecalc;
COMMIT TRAN
   drop table if exists tbPrecalc_EmptyPhantom
END TRY

END