We know how to write code to do something now. What about code to do something tomorrow, or next year? Sometimes we use batch jobs. But as business grows, our "overnight" batch job starts finishing around lunch time. As we expand to new regions, we realise there is no "night". And it's only a matter of time before we make a change and break a batch job we forgot existed. What if tomorrow's code could live in the same place as today's code? What if it all looked the same? What if we could scale it all the same way? Join Adam and discover how to embrace the future in the code we write now. Learn how to capture requirements as first class business logic, and avoid relegating them to second class citizens of the batch job world. Take a deep dive into techniques which combine off the shelf products with fundamental computer science.

5. SUM=90

6. BATCH JOB

8. WITH ct AS
(
SELECT
id = cid,
total = SUM(value)
FROM orders
WHERE date > …
GROUP BY cid
)
UPDATE c
SET c.Discount = 10
FROM customers AS c
INNER JOIN ct
ON c.id = ct.id
WHERE ct.total > …;
USE tempdb;
GO
DECLARE @x TABLE (ID int,
Value int);
DECLARE @y TABLE (ID int,
Value int);
INSERT @x VALUES (1, 10), (2,
20);
INSERT @y VALUES (1, 100),(2,
200);
WITH cte AS (SELECT * FROM
@x)
UPDATE cte -- cte is not
referenced by the alias.
SET Value = y.Value
FROM cte AS x -- cte is
assigned an alias.
INNER JOIN @y AS y ON y.ID =
x.ID;
SELECT * FROM @x;
GO
USE tempdb;
GO
-- UPDATE statement with CTE references
that are correctly matched.
DECLARE @x TABLE (ID int, Value int);
DECLARE @y TABLE (ID int, Value int);
INSERT @x VALUES (1, 10), (2, 20);
INSERT @y VALUES (1, 100),(2, 200);
WITH cte AS (SELECT * FROM @x)
UPDATE x -- cte is referenced by the
alias.
SET Value = y.Value
FROM cte AS x -- cte is assigned an
alias.
INNER JOIN @y AS y ON y.ID = x.ID;
SELECT * FROM @x;
GO
USE AdventureWorks2012;
GO
IF OBJECT_ID ('dbo.Table1', 'U') IS NOT NULL
DROP TABLE dbo.Table1;
GO
IF OBJECT_ID ('dbo.Table2', 'U') IS NOT NULL
DROP TABLE dbo.Table2;
GO
CREATE TABLE dbo.Table1
(c1 int PRIMARY KEY NOT NULL, c2 int NOT NULL);
GO
CREATE TABLE dbo.Table2
(d1 int PRIMARY KEY NOT NULL, d2 int NOT NULL);
GO
INSERT INTO dbo.Table1 VALUES (1, 10);
INSERT INTO dbo.Table2 VALUES (1, 20), (2, 30);
GO
DECLARE abc CURSOR LOCAL FOR
SELECT c1, c2
FROM dbo.Table1;
OPEN abc;

11. 1 week
Sum(o => o.Total)
t

12. += o1.Total
-= o1.Total
1 week
+= o2.Total
-= o2.Total
1 week
+= o3.Total
-= o3.Total
1 week
WeekTotal WeekTotal
t

14. SAGA
docs.particular.net/nservicebus/sagas/

15. += o1.Total
-= o1.Total
1 week
+= o2.Total
-= o2.Total
1 week
+= o3.Total
-= o3.Total
1 week
WeekTotal WeekTotal
t

16. SHOW ME THE CODE

17. DB
BUS
SAGA
class Discounting :
Saga<Discounting.Data>
{
public async Task Handle(
SubmitOrder order)
{
...
}
...
}
Persist
er
dispatch message
queue
request timeout
persist timeout
delay
persist saga
poll

18. AMAZON SQS
600 s
900
2,800 s
100 s
900
900
(1,900)
(1,000)
(100)

19. RABBITMQ
600 s
900 s
1,500 s
2,800 s

20. RABBITMQ

21. RABBITMQ
42 seconds
1010102 seconds
4210 seconds

22. RABBITMQ
1
1
0
0
1
0
32 s
16 s
8 s
4 s
2 s
1 s
(4210)

23. RABBITMQ
28 queues
228 seconds
268,435,456 seconds
8.5 years

24. WT=90

25. DB
queue
BUS
SAGA
class OrderProcessPolicy : Saga<OrderProcess>
{
public async Task Handle(SubmitOrder order)
{
// ...
}
public async Task Handle(Cancel
{
// ..
}
public async Task Timeout(BuyersRemorse state)
{
// ...
}
}
Persi
ster
create saga
dispatch message
send messages
persist saga
BUS
SAGA
class OrderProcessPolicy : Saga<OrderProcess>
{
public async Task Handle(SubmitOrder order)
{
// ...
}
public async Task Handle(Cancel
{
// ..
}
public async Task Timeout(BuyersRemorse state)
{
// ...
}
}
Persi
ster
create saga
dispatch message
send messages
persist saga
persist saga
CustomerId = 1337
persist saga
CustomerId = 1337
message(s) sent message(s) not sent
message(s) sent

26. BATCH JOB
particular.net/blog/death-to-the-batch-job

30. Automated pattern matching
Daily reports
saga
notification
business events

33. go.particular.net/netfwdays

34. go.particular.net/
netfwdays
CODE THE FUTURE,
NOW