Partizionamento a livello di applicazioneApplication-Level Partitioning

Questa applicazione elabora gli ordini.This application processes orders. Gli ordini recenti vengono sottoposti a numerose elaborazioni.There is a lot of processing on recent orders. Gli ordini meno recenti non vengono sottoposti a numerose elaborazioni.There is not a lot of processing on older orders. Gli ordini recenti sono in una tabella ottimizzata per la memoria.Recent orders are in a memory-optimized table. Gli ordini meno recenti sono in una tabella basata su disco.Older orders are in a disk-based table. Tutti gli ordini dopo hotDate sono nella tabella ottimizzata per la memoria.All orders after the hotDate are in the memory-optimized table. Tutti gli ordini prima di hotDate sono nella tabella basata su disco.All orders before the hotDate are in the disk-based table. Si supponga un pesante carico di lavoro OLTP con molte transazioni simultanee.Assume an extreme OLTP workload with a lot of concurrent transactions. Questa regola di business (ordini recenti in una tabella ottimizzata per la memoria) deve essere applicata anche se diverse transazioni simultanee stanno tentando di modificare hotDate.This business rule (recent orders in a memory-optimized table) must be enforced even if several concurrent transactions are attempting to change the hotDate.

In questo esempio non viene utilizzata una tabella partizionata della tabella basata su disco ma si tiene traccia di un punto di divisione esplicito tra le due tabelle, utilizzando una terza tabella.This sample does not use a partitioned table for the disk-based table but does track an explicit split point between the two tables, using a third table. Il punto di divisione può essere usato per garantire che i dati appena aggiunti vengano inseriti sempre nella tabella appropriata in base alla data.The split point can be used to ensure that newly inserted data is always inserted into the appropriate table based on the date. Inoltre, può essere usato per determinare la posizione in cui cercare i dati.It could also be used to determine where to look for data. I dati che arrivano in ritardo vengono ancora inseriti nella tabella appropriata.Late arriving data still goes into the appropriate table.

Per un esempio correlato, vedere Modello di applicazione per il partizionamento di tabelle con ottimizzazione per la memoria.For a related sample, see Application Pattern for Partitioning Memory-Optimized Tables.

Listato di codiceCode Listing

USE MASTER  
GO  
IF NOT EXISTS(SELECT name FROM sys.databases WHERE name = 'hkTest')  

CREATE DATABASE hkTest  
-- enable for In-Memory OLTP - change file path as needed  
ALTER DATABASE hkTest ADD FILEGROUP hkTest_mod CONTAINS MEMORY_OPTIMIZED_DATA  
ALTER DATABASE hkTest ADD FILE( NAME = 'hkTest_mod' , FILENAME = 'c:\data\hkTest_mod') TO FILEGROUP hkTest_mod;  
GO  

use hkTest  
go  

-- create memory-optimized table   
if OBJECT_ID(N'hot',N'U') IS NOT NULL  
   drop table [hot]  

create table hot   
   (id int not null primary key nonclustered,  
   orderDate datetime not null,  
   custName nvarchar(10) not null  
) with (memory_optimized=on)  
go  

-- create disk-based table for older order data  
if OBJECT_ID(N'cold',N'U') IS NOT NULL  
   drop table [cold]  

create table cold (  
   id int not null primary key,   
   orderDate datetime not null,   
   custName nvarchar(10) not null  
)  
go  

-- the hotDate is maintained in this memory-optimized table. The current hotDate is always the single date in this table  
if OBJECT_ID(N'hotDataSplit') IS NOT NULL  
   drop table [hotDataSplit]  

create table hotDataSplit (  
   hotDate datetime not null primary key nonclustered hash with (bucket_count = 1)  
) with (memory_optimized=on)  
go  

--  Stored Procedures  
--  set the hotDate  
--  snapshot: if any other transaction tries to update the hotDate, it will fail immediately due to a  
--  write/write conflict  
if OBJECT_ID(N'usp_hkSetHotDate') IS NOT NULL  
   drop procedure usp_hkSetHotDate  
go  

create procedure usp_hkSetHotDate @newDate datetime  
   with native_compilation, schemabinding, execute as owner  
   as begin atomic with  
   (  
      transaction isolation level = snapshot,  
      language = N'english'  
   )  

   delete from dbo.hotDataSplit  
   insert dbo.hotDataSplit values (@newDate)  
   end  
go  

-- extract data up to a certain date [presumably the new hotDate]  
-- must be serializable, because you don't want to delete rows that are not returned  
if OBJECT_ID(N'usp_hkExtractHotData') IS NOT NULL  
   drop procedure usp_hkExtractHotData  
go  
create procedure usp_hkExtractHotData @hotDate datetime  
   with native_compilation, schemabinding, execute as owner  
   as begin atomic with  
   (  
      transaction isolation level = serializable,  
      language = N'english'  
)  
   select id, orderDate, custName from dbo.hot where orderDate < @hotDate  
   delete from dbo.hot where orderDate < @hotDate  
end  
go  

-- insert order  
-- inserts an order either in recent or older table, depending on the current hotDate  
-- it is important that the SP for retrieving the hotDate is repeatableread, in order to ensure that  
-- the hotDate is not changed before the decision is made where to insert the order  
-- note that insert operations [in both disk-based and memory-optimized tables] are always fully isolated, so the transaction  
-- isolation level has no impact on the insert operations; this whole transaction is effectively repeatableread  
if OBJECT_ID(N'usp_InsertOrder') IS NOT NULL  
   drop procedure usp_InsertOrder  
go  

create procedure usp_InsertOrder(@id int, @orderDate date, @custName nvarchar(10))  
   as begin  
   SET TRANSACTION ISOLATION LEVEL READ COMMITTED  
   begin tran  
      -- get hot date under repeatableread isolation; this is to guarantee it does not change before the insert is executed  
      declare @hotDate datetime  
      set @hotDate = (select hotDate from hotDataSplit with (repeatableread))  

      if (@orderDate >= @hotDate) begin  
         insert into hot values (@id, @orderDate, @custName)  
      end  
      else begin  
         insert into cold values (@id, @orderDate, @custName)  
      end  
   commit tran  
end  
go  

-- change hot date  
-- changes the hotDate and moves the rows between the recent and older order tables as appropriate  
-- the hotDate is updated in this transaction; this means that if the hotDate is changed by another transaction  
--   the update will fail due to a write/write conflict and the transaction is rolled back  
--   therefore, the initial (snapshot) access of the hotDate is effectively repeatable read  
if OBJECT_ID(N'usp_ChangeHotDate') IS NOT NULL  
   drop procedure usp_ChangeHotDate  
go  
create procedure usp_ChangeHotDate(@newHotDate datetime)  
as  
begin  
   SET TRANSACTION ISOLATION LEVEL READ COMMITTED  
   begin tran  
       declare @oldHotDate datetime  
      set @oldHotDate = (select hotDate from hotDataSplit with (snapshot))  

       -- get hot date under repeatableread isolation; this is to guarantee it does not change before the insert is executed  
      if (@oldHotDate < @newHotDate) begin  
         insert into cold exec usp_hkExtractHotData @newHotDate  
      end  
      else begin  
         insert into hot select * from cold with (serializable) where orderDate >= @newHotDate  
         delete from cold with (serializable) where orderDate >= @newHotDate  
      end  
      exec usp_hkSetHotDate @newHotDate  
   commit tran  
end  
go  

--  Deploy and populate tables  
-- cleanup  
delete from cold  
go  

-- init hotDataSplit  
exec usp_hkSetHotDate '2012-1-1'   
go  

-- verify hotDate  
select * from hotDataSplit  
go  

EXEC usp_InsertOrder 1, '2011-11-14', 'cust1'  
EXEC usp_InsertOrder 2, '2012-3-4', 'cust1'  
EXEC usp_InsertOrder 3, '2011-1-23', 'cust1'  
EXEC usp_InsertOrder 4, '2011-8-6', 'cust1'  
EXEC usp_InsertOrder 5, '2010-11-1', 'cust1'  
EXEC usp_InsertOrder 6, '2012-1-9', 'cust1'  
EXEC usp_InsertOrder 7, '2012-2-14', 'cust1'  
EXEC usp_InsertOrder 8, '2010-1-17', 'cust1'  
EXEC usp_InsertOrder 9, '2012-3-8', 'cust1'  
EXEC usp_InsertOrder 10, '2011-9-24', 'cust1'  
go  

--  Demo Portion  
-- verify contents of the tables  
-- hotDate is 2012-1-1  
-- all orders from 2012 are in the recent table  
-- all orders before 2012 are in the older order table  

-- query hot data  
select * from hot order by orderDate desc  

-- query cold date  
select * from cold order by orderDate desc  

-- move hot date to Mar 2012  
EXEC usp_ChangeHotDate '2012-03-01'  

-- Verify that all orders before Mar 2012 were moved to older order table  
-- query hot data  
select * from hot order by orderDate desc  

-- query old data  
select * from cold order by orderDate desc  

Vedere ancheSee Also

Esempi di codice di OLTP in memoriaIn-Memory OLTP Code Samples