Asynchronous I/O in NodeJS - new standard or challenges?
•Download as ODP, PDF•
9 likes•2,443 views
![Notice ,[object Object]](data:image/gif;base64,R0lGODlhAQABAIAAAAAAAP///yH5BAEAAAAALAAAAAABAAEAAAIBRAA7)
Recommended
More Related Content
What's hot
What's hot (20)
Viewers also liked
Viewers also liked (20)
Similar to Asynchronous I/O in NodeJS - new standard or challenges?
Similar to Asynchronous I/O in NodeJS - new standard or challenges? (20)
Recently uploaded
Recently uploaded (20)
Asynchronous I/O in NodeJS - new standard or challenges?
- 1. Asynchronous I/O in NodeJS - Standard and challenge of web programming? Pham Cong Dinh @ SkunkWorks @pcdinh BarCamp Saigon 2011 Follow us on Twitter: @teamskunkworks
- 3. Things can be changed
- 4. No standard at the moment
- 5. Unix only
- 7. JVM
- 9. Events / Non-blocking I/O From http://bethesignal.org/
- 11. Threads: A process contains multiple threads. A single thread is assigned to handle an incoming request. Thread-per-request model
- 12. Events: A process consists of the processing of a series of events. At any instant in time, a single event/request is being processed. The process is not blocked on I/O request.
- 13. Request handling: Process / Threads / Events Threads shares ● D efault share memor y ● F ile descriptors ● Filesystem context ● Signals and S ignal handling
- 14. Request handling: Process / Threads / Events Thread creation is expensive - From iobound.com
- 15. Request handling: Process / Threads / Events Context switching is expensive
- 16. Request handling: Process / Threads / Events Blocking model: Process and Threads
- 17. Request handling: Process / Threads / Events Non-blocking model: Events
- 18. Request handling: Event-driven IO loop issue poll vs. epoll epoll: O(1) or O(n=active)
- 19. Request handling: Event-driven callback issues Non-blocking IO Loop vs. Blocking callback Event dispatching is not blocked Callback can be blocked Mixing asynchronous code and synchronous code can be bad
- 21. libeio for asynchonous file I/O
- 22. c-ares for asynchronous DNS requests and name resolution.
- 23. evcom (by Ryan Dahl) is a stream socket library on top of libev.
- 25. Most “objects” in NodeJS are Event Emitters (http server/client, etc.)
- 26. Most low level “functions” take callbacks. (posix API, DNS lookups, etc.) Blocking code var a = db.query('SELECT A'); console.log('result a:', a); Non-blocking code using callback db.query('SELECT A', function(result) { console.log('result a:', result); });
- 28. Do things in a specific order.
- 29. You must keep track of what is done at a point of time
- 30. Hard to handle failures
- 31. Nested callbacks can be hard to read