Embed Size (px)
Citation preview
OpenBlend LjubljanaSeptember 15th, 2011
Sanne GrinoveroSoftware Engineer at Red Hat
About me• Hibernate
• Hibernate Search
• Hibernate OGM
• Infinispan
• Lucene Directory
• Infinispan Query
in.relation.to/Bloggers/Sanne
Twitter: @SanneGrinovero
What is Hibernate OGM ?
JPA for NoSQL
• initially Key/Value store• in particular Infinispan
Relational Databases• Transactions • Referential integrity• Simple Types• Well understood- tuning, backup, resilience
Relational Databases
But scaling is hard!-Replication-Multiple instances w/ shared disk-Sharding
Relational Databases on a cloud
Master/replicas: which master?
A single master? I was promised elasticity
Less reliable “disks”
IP in configuration files? DNS update times?
Who coordinates this? How does that failover?
¬SQLbeing a not-only-thatone
basically makes it a definition of “everything else too”
“no-category”
No-SQL goalsVery different• Large datasets• High availability• Low latency / higher throughput• Specific data access pattern• Specific data structures• ...
• Document based stores • Column based • Graph oriented databases• Key / value stores• Full-Text Search
NotOnlySQL
Flexibility at a cost
•Programming model•one per product :-(
•no schema => app driven schema•query (Map Reduce, specific DSL, ...)•data structure transpires•Transaction•durability / consistency
Quick Infinispan introduction
Distributed Key/Value store•(or Replicated, local only efficient cache, invalidating cache)
Each node is equal•Just start more nodes, or kill some
No bottlenecks•by design
Cloud-network friendly•JGroups•And “cloud storage” friendly too!
Infinispan ABC
map.put( “user-34”, userInstance );
map.get( “user-34” );
map.remove( “user-34” );
It's a ConcurrentMap !
map.put( “user-34”, userInstance );
map.get( “user-34” );
map.remove( “user-34” );
map.putIfAbsent( “user-38”, another );
Something more about Infinispan
● Support for Transactions (XA)● CacheLoaders
●Cassandra, JDBC, Amazon S3 (jclouds),...● Tree API for JBossCache compatibility● Lucene integration
● Two-fold● Some Hibernate integrations
● Second level cache● Hibernate Search indexing backend
Cloud-hack experiments
Let's abuse of Hibernate's second level cache design, using Infinispan's implementation:- usually configured in clustering mode INVALIDATION. Let's use DIST instead.- Disable expiry/timeouts.
What's the effect on your cloud-deployed database?
Cloud-hack experiments
Now introduce Hibernate Search: - full-text queries should be handled by Lucene, NOT by the database.
Hibernate Search identifies hits from the Lucene index, but loads them by PK. *by default
Cloud-hack experiments
Load by PK ->second level cache ->
Key/Value store
FullText query ->Hibernate Search ->
Lucene Indexes
Cloud-hack experiments
Load by PK ->second level cache ->
Key/Value store
FullText query ->Hibernate Search ->
Lucene Indexes
So what if you shut down the database?
Cloud-hack experimentsLoad by PK ->
second level cache ->Key/Value store
FullText query ->Hibernate Search ->
Lucene Indexes
So what if you shut down the database?•No relational/SQL queries•You won't be able to write!
Goals
•Encourage new data usage patterns•Familiar environment•Ease of use•easy to jump in•easy to jump out•Push NoSQL exploration in enterprises•“PaaS for existing API” initiative
What it does
•JPA front end to key/value stores•Object CRUD (incl polymorphism and associations)•OO queries (JP-QL)
•Reuses•Hibernate Core•Hibernate Search (and Lucene)•Infinispan
•Is not a silver bullet•not for all NoSQL use cases
Concepts
Schema or no schema?
•Schema-less•move to new schema very easy•app deal with old and new structure or migrate all
data•need strict development guidelines
•Schema•reduce likelihood of rogue developer corruption•share with other apps•“didn’t think about that” bugs reduced
Entities as serialized blobs?
•Serialize objects into the (key) value•store the whole graph?
•maintain consistency with duplicated objects•guaranteed identity a == b•concurrency / latency•structure change and (de)serialization, class definition
changes
OGM’s approach to schema
•Keep what’s best from relational model•as much as possible•tables / columns / pks
•Decorrelate object structure from data structure•Data stored as (self-described) tuples•Core types limited
•portability
OGM’s approach to schema
•Store metadata for queries•Lucene index
•CRUD operations are key lookups
• Entities are stored as tuples (Map<String,Object>) • The key is composed of
• table name• entity id
• Collections are represented as a list of tuple- The key is composed of:
• table name hosting the collection information• column names representing the FK• column values representing the FK
How does it work?
Queries
•Hibernate Search indexes entities•Store Lucene indexes in Infinispan•JP-QL to Lucene query transformation
•Works for simple queries•Lucene is not a relational SQL engine
select a from Animal a where a.size > 20
> animalQueryBuilder.range().onField(“size”).above(20).excludeLimit().createQuery();
select u from Order o join o.user u where o.price > 100 and u.city = “Paris”> orderQB.bool() .must( orderQB.range() .onField(“price”).above(100).excludeLimit().createQuery() ) .must( orderQB.keyword(“user.city”).matching(“Paris”) .createQuery()).createQuery();
Demo
Why Infinispan?
•We know it well•Supports transactions (!)
•Research is going on to provide “cloud transactions” on more platforms
•It supports Lucene indexes distribution•Easy to manage in clouds•It's a key/value store with support for Map/Reduce
•Simple•Likely a common point for many other “databases”
Why Infinispan?
•Map/Reduce as an alternative to indexed queries•Might be chosen by a clever JP-QL engine
•Supports – experimentally – distributed Lucene queries•Since ISPN-200, merged last week
Why all this ?
Developers will only need to think about
• JPA models
• JP-QL queries
Everything else is perfomance tuning, including:
•Move to/from different NoSQL implementations
•Move to/from a SQL implementation
•Move to/from clouds/laptops
•JPA is a well known standard: move to/from Hibernate :-)
Summary•JPA for NoSQL•Reusing mature projects•Keep the good of the relational model•Query via Hibernate Search
•JP-QL support on its way•Still early in the project•Only Infinispan is integrated: contributions welcome!
Summary
•Performance / scalability is different•Isolation is different
http://www.jboss.org/jbw2011keynote.htmlhttps://github.com/Sanne/tweets-ogm
Q + A
