Pat Helland and me: How to build stateful distributed applications that can scale almost infinitely

In 2007, Pat Helland published “Life Beyond Distributed Transactions: An Apostate’s Opinion,” in which he conducts a thought experiment on how to design a distributed database that can scale almost infinitely. While the paper explicitly addresses distributed database design, Sean Allen shows that the ideas are far more widely applicable, particularly in scaling stateful applications. Sean explores some of Helland’s ideas through practical examples from his experience building data processing systems using tools like Apache Storm and, more recently, developing a stateful distributed stream processor at Wallaroo Labs.

Transcript

1. PAT HELLAND AND ME HOW TO BUILD STATEFUL DISTRIBUTED APPLICATIONS THAT CAN SCALE ALMOST INFINITELY
2. PAT HELLAND AND ME
3. SEAN T. ALLEN VP OF ENGINEERING AT WALLAROO LABS MEMBER OF THE PONY CORE TEAM AUTHOR OF “STORM APPLIED” LOVER OF FRENCH STREET ART @SEANTALLEN @WALLAROOLABS @PONYLANG
4. DATABASES APPARENTLY, I LIKE TO STICK THEM IN THINGS…
5. SOME AXIOMS…
6. TO SCALE INFINITELY, WE HAVE TO SCALE HORIZONTALLY
7. TO SCALE INFINITELY, WE MUST AVOID COORDINATION
8. DISTRIBUTED TRANSACTIONS ARE A FORM OF COORDINATION
9. THEREFORE… TO SCALE INFINITELY, WE CAN’T USE TRANSACTIONS
10. WELCOME TO DISTRIBUTED SYSTEMS! O, BY THE WAY, ALL THE RULES HAVE CHANGED
11. WHAT IS SCALING?
12. MORE AND MORE THINGS BUT, THEY DON’T GET BIGGER. THERE’S JUST… MORE OF THEM. LOTS MORE.
13. WE SCALE ENTITIES ENTITIES: LIVE ON A SINGLE MACHINE AND ARE MANIPULATED INDIVIDUALLY
14. WHAT IS AN ENTITY?
15. ENTITIES ARE BOUNDARIES OF ATOMICITY
16. Bob 6 3 5 8 Alice 4 2 7 1
17. Bob 6 3 5 8 Alice 4 2 7 1
18. Bob 6 3 5 8 Alice 4 7 1 2
19. Bob 6 3 5 8 Alice 4 2 7 1
20. Bob 6 3 5 8 Alice 4 2 7 1
21. DENORMALIZE.. ALL THE THINGS!
22. TWO LAYER ARCHITECTURE
23. scale-agnostic scale-aware API
24. scale-agnostic scale-aware API
25. scale-agnostic scale-aware API
26. scale-agnostic scale-aware API
27. scale-agnostic scale-aware API
28. scale-agnostic scale-aware API
29. TO SCALE INFINITELY, YOUR BUSINESS LOGIC HAS TO BE INDEPENDENT OF SCALE
30. WALLAROO SCALE INDEPENDENT COMPUTING FOR PYTHON
31. AND IT’S NOT A DATABASE
32. ENTITIES BUT WE CALL THEM… “STATE OBJECTS”
33. TWO LAYER ARCHITECTURE BUT WE CALL IT… “SCALE INDEPENDENCE”
34. user supplied logic Wallaroo runtime Wallaroo API
35. user supplied logic Wallaroo runtime Wallaroo API
36. user supplied logic Wallaroo runtime Wallaroo API
37. user supplied logic Wallaroo runtime Wallaroo API
38. WHAT’S HARD? ALL OF IT? YOU’RE BUILDING A DISTRIBUTED SYSTEMS *FRAMEWORK*
39. CAP THEOREM CONSISTENCY VS AVAILABILITY… YOU CAN’T ESCAPE IT.
40. MESSAGE DELIVERY AT-MOST-ONCE? AT-LEAST- ONCE? EFFECTIVELY-ONCE? EXACTLY-ONCE?
41. MESSAGE ORDERING WILL YOU MAINTAIN THE ORDERING AS YOU RECEIVED IT?
42. LOCAL KNOWLEDGE YOU HAVE TO WORK HARD TO AVOID COORDINATION.
43. PROGRAMMING MODEL YOU CAN GET WITH THIS, OR YOU CAN GET WITH THAT.
44. PERFORMANCE IT’S A WORD IN THE DICTIONARY
45. NETWORK OVERHEAD YOU AREN’T IN LOCAL MEMORY ANYMORE
46. DATA SERIALIZATION LE SIGH…
47. VERIFICATION LET’S NOT GO THERE… THAT’S AN ENTIRE LECTURE SERIES.
48. BTW… YOUR MULTI-CORE COMPUTER IS ALSO A DISTRIBUTED SYSTEM. BUT THAT’S A STORY FOR ANOTHER DAY.
49. LEARN MORE GITHUB.COM/SEANTALLEN/ PAT-HELLAND-AND-ME