Thinking in a document centric world with RavenDB by Nick Josevski
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RavenDB is a document database built with .NET that uses an index store for queries and a document store for single document loads. It supports eventual consistency through indexing where the index may be stale. Documents can contain complex object graphs and the database is schema-free. Queries use LINQ and documents can be loaded with associated documents using session.Include. Indexes must be defined for fields to be queryable and mappers can be used for multi-type queries or aggregation. Profiling is integrated for ASP.NET applications and documents are typically structured as single documents, parent/child relationships, or networks of documents.
Thinking in a document centric world with RavenDB by Nick Josevski
- 1. Thinking in a document centric world with RavenDB
- 2. There’s got to be a better way, Somewhere over the…
- 3. We’re off to see the Wizard
- 5. What is RavenDB? • • • • • • • It is a Document Store Built with .NET Fast Easy to use / program against Currently only runs on Windows If you’re wondering it supports MSDTC Open source
- 7. CAP Theorem • Consistency • Availability • Partition Tolerance • When you suffer a network partition between stores. • You decide how much Consistency OR Availability you would like to have.
- 8. Documents are not flat • A single document can be a complex object graph. • It’s no longer a challenge to store your data • You’re no longer in a relational world – Schema-free data store – Does not mean chaos as some would lead you to believe More info on this at: http://ravendb.net/docs/theory/document-structure-design
- 9. Eventual Consistency • In RavenDB – Writes occur against the document store. – Queries occur against the index store. – Single Load operations go directly to the document store. • RavenDB is more consistent than others • Also: not all viewers of data should be considered equal.
- 10. Eventual Consistency • Step 1 : Optimise for reading, • Step 2: by prioritising Availability higher than Consistency • Step 3: (Index is stale) • Step 4: Profit
- 11. GETTING STARTED
- 12. Installation
- 14. USING RAVEN DB
- 15. Using Raven in your .NET Code
- 16. Just like any (good) ORM • Persist Document • Loading • Queries
- 17. Unit of Work Pattern • With IDocumentSession – Open a session of work – Make changes in memory – Persist changes
- 18. Search Capabilities • Search is delegated to Lucene.NET – Full text indexing
- 19. FETCH / QUERY
- 20. Session.Include • The simplest way to start retrieving documents and other associated documents
- 21. Session.Query • It is just LINQ • Pagination via: – .Skip() and .Take()
- 22. Session.Customize • As part of a query retrieve associated documents
- 23. Safe by Default • 3 magic numbers to help you out – Default page size limit 128 – Take(n > 1024) is still 1024 – Requests 30 • Why so many calls? • Overridable via configuration, for those SELECT * FROM addicts
- 24. Transformers • Server side projections – with the ability load data from other documents – RavenDBs true power shining through
- 28. INDEXES
- 29. Indexes • With the power of schema-less store • Comes great (some) responsibility • Raven doesn’t know about fields on your document by default • So if you haven’t set up indexes raven will help you out
- 30. Indexes • Extend Abstract Index Creation Task
- 31. Map / Reduce • Just like previous examples except there’s a reduce component • Most trivial examples is summing up totals/counts of items
- 32. Map / Reduce
- 33. Multi-Map • Querying Unlike Documents • To build up something that doesn’t exist • We’re working with documents – No need for left/inner/outer/right/middle joins
- 34. Multi-Map
- 36. PROFILING
- 37. Profiling is first class • Fiddler is your friend
- 38. ASP.NET Profiling Integration • For your ASP.NET MVC App 1. 2. 3. • In Global.asax.cs In _layout.cshtml Demo app up at: https://github.com/NickJosevski/ravendb-presentation
- 40. More in the REAL WORLD
- 41. Raven in Apps
- 42. Structure of our Documents • Varies and has been tuned for each use case • But can be summarised into 3 types
- 44. Single Documents
- 45. Single Documents
- 46. Parent & Child Documents
- 47. 4th type and no longer used • When we started with Raven • We started down a path of “Summary” Documents – Which became a problem to maintain • Replaced with Transformers outputting SummaryDTOs
- 51. Projectors
- 52. More Info / Sources • • • • http://ravendb.net/ Tekpub (series now on Pluralsight) RavenDB High Performance by Brian Ritchie NoSQL video from Martin Fowler – http://www.youtube.com/watch?v=qI_g07C_Q5I • Reach out to me Nick Josevski – 1st video recording of this: – http://www.youtube.com/watch?v=u3kUpFlf76M
Editor's Notes
- #2: Here to talk to you about RavenDb
- #3: Solutions to a lot of software development problems still get solved using relational databases as a default
- #4: I’m going to take you on a journey
- #5: There’s a wonderful place where interacting with your DataStore is no longer a frustration.
- #6: Document Store.NETFast & Easy to use/program against
- #8: It’s not one over the other.It can’t be a talk in the noSQL space without bringing this up.
- #9: Does not mean ChaosSpend the time to think about structureSchema-free data store, that doesn't mean that you shouldn't take some time to consider how to design your documents to ensure that you can access all the data that you need to serve user requests efficiently, reliably and with as little maintainability cost as possible.
- #10: Explain the 2 stores.Writes are ASYNCPerformance gain – Writes don’t hold up reads use the apple inventory example here.Index is set as stale when a write has happened, and Raven is updating the index. Not the same EC like in Casandra where in those it's about writes.It is optimized for reads by prioritizing Availability higher than Consistency. RavenDB is not unique in this regard, but it is somewhat special in that it still has the ability to be consistent. If you are retrieving single document, such as reviewing an order or an end user viewing their profile, these operations are ACID compliant, and are not affected by the "eventual consistency" design.
- #11: To summariseRemember this does not mean “lack of consistency” it simply means prioritised over.A sales person goes to a "products list" page that is sorted alphabetically.On the first page, they see that "Apples" aren't currently being sold.So they click "add product", and go to a new page where they enter "Apples".They are then returned to the "products list" page and they still don't see any Apples because the index is stale. WTF - right?Embrace this and you’ll be a much happier software developer!
- #14: Open up raven management studio
- #16: NUGET and you’re done!
- #17: Sesion is Raven.Client.IDocumentSessionQueries with Linq. In fact you don’t need an ORM like EF/Nhib you just write linqepressions after you include the Raven.Client assembly.If you’ve ever used any kind of ORM, this is very straight forwardBasicsStore,Retrieve,Query
- #18: Use of raven document session followsUnit of Work pattern
- #19: Delegated to LucenePowerful search engine (a whole different talk)
- #21: Not joins, forget about joins.On like 24 we’re linking to a very common external document, one that represents a user (in this case an assignee)On line 25 we’re linking out to another separately stored document participants
- #22: Standard paging by usingResults Per Page & Page Number
- #23: Show fiddlerNEED A LESS CONFUSING LIST OF .Customize() calls
- #24: Don’t shoot your own foot off128 = default page size1024 = page size limit as per safe by default30 is the hey why are you talking to raven so much over the wire
- #25: Are awesome!Server side projectionsWith loading!Run inside raven!
- #26: Simple Mapping
- #27: We can come back to this slide if people are interested.I wanted to include it, if this came up as a question, or at least to give a glimpse of their power
- #28: The nested transformer
- #29: Remember at the start I mentioned we have the ‘document store’ and the ‘index store’
- #30: You should set up your own indexes, here’s how you do it
- #32: Need a more interesting example
- #33: Sorry but this is it, our example of map reduce is quite complex
- #34: Like a viewOur library (DAM) is a good example, a variety of items get organised into buckets, but we need to show them all together, the user doesn’t care what it technically is while browsing around
- #35: That leads into Multi-Map
- #39: Fiddler is your friend
- #49: This is where you go and find your indexes that extend Abstract Index Creation TaskAnd the transformers
- #50: Autofac registration code.The lines of note are 86 – pulling from a configuration the location of the databaseLine 92 our replication setup96-100 port exhaustion issue we saw in production109-111 regular Autofac lifetime management
- #52: With the help of IoC when an event occurs in our CQRS style applicationA projector will get given the correct document from raven, we simply manipulate that documentWhen the raven session ends (request ends) the changes get savedLines of note 31: our tie/link to an event stream aggregate33-36 onevent handlers39 simplest example45 one of these per