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![CRUD Demo time
show dbs view existing databases
use test use database “test”
db.t.insert({name:’bob’,age:’30’}) insert 30 years bob
db. t.insert({name:’alice’,gender:’female’}) insert lady alice
db. t.find() list all documents in collection t
db. t.find({name:’bob’},{age:1}) find 1 year old bob
db. t.find().limit(1).skip(1) find the second document
db. t.find().sort({name:1}) sort the results with ascend name
db. t.find({$or:[{name:’bob’},{name:’tom’}]}) find bob or tom’s documents
db. t.update({name:’ bob’},{$set:{age:31}}, update all bob’s age to 31
false,true})
db.stats() database statistic
db.getCollectionNames() collections under this db
db.t.ensureIndex({name:1}) create index on name
db.people.find({name:“bob"}).explain() explain plan step](https://image.slidesharecdn.com/mongodbintroductionandinternalsimple-120201092922-phpapp02/85/Mongodb-introduction-and_internal-simple-5-320.jpg)
![MongoDB Sharding: Briefly
Sequence
FROM:C TO:N
#Make sure my view is complete and lock
#Get the document’s DiskLoc for sharding
#Trigger the N to sharding in Pull mode
#Copy Index Definition from C
#Remove existing data in [min~max]
#Clone the data in[min~max] from C
#Ask C to replicate the changes
#Ask N to commit
#N commit](https://image.slidesharecdn.com/mongodbintroductionandinternalsimple-120201092922-phpapp02/85/Mongodb-introduction-and_internal-simple-10-320.jpg)
Uploaded byKai Zhao
Mongodb introduction and_internal(simple)
Here are 3 key questions about MongoDB: 1. What is MongoDB? MongoDB is an open source, document-oriented, NoSQL database that provides high performance, high availability, and automatic scaling. It stores data in flexible, JSON-like documents, allowing for schema-less design. 2. How does MongoDB handle large data? MongoDB uses a concept called GridFS to break files into chunks and store metadata about the file in the database. This allows for efficient storage and retrieval of large files. 3. How does MongoDB scale? MongoDB scales horizontally by sharding data across multiple servers. It splits collections into chunks which can be distributed across shards. The balancer component monitors shard loads and migrates chunks between shards for improved distribution
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- 1. MongoDB Introduction and Internal byKai Zhao 2011.12 kingaim@gmail.com
- 2. What is MongoDB? •Opensource, scalable, high-performance, document-oriented NoSQL Key-Value based database. •Features •JSON-style document –oriented storage with schema-less •B-tree index supported on any attribute •Log-based replication for Master/Slave and Replica Set •Auto-sharding architecture (via horizontal partition) scales to thousands of nodes •NoSQL-style query •Surprising updating behaviors •Map/Reduce support •GridFS specification for storing large files •Developed by 10gen with commercial support
- 3. Well/Less Well Suited Source: http://www.mongodb.org/display/DOCS/Use+Cases
- 4. Basic concepts inMongoDB MongoDB Relational DBMS Databases* Databases* Collections* Relations* Documents* Indexes* Columns* Indexes* Fields* NoSQL MongoDB Relational DBMS Each document has its own fields and Database Database makes MongoDB schema-less. Collection Relation Document Tuple Field Column Index Index Cursor Cursor * means 0 or more objects
- 5. CRUD Demo time show dbs view existing databases use test use database “test” db.t.insert({name:’bob’,age:’30’}) insert 30 years bob db. t.insert({name:’alice’,gender:’female’}) insert lady alice db. t.find() list all documents in collection t db. t.find({name:’bob’},{age:1}) find 1 year old bob db. t.find().limit(1).skip(1) find the second document db. t.find().sort({name:1}) sort the results with ascend name db. t.find({$or:[{name:’bob’},{name:’tom’}]}) find bob or tom’s documents db. t.update({name:’ bob’},{$set:{age:31}}, update all bob’s age to 31 false,true}) db.stats() database statistic db.getCollectionNames() collections under this db db.t.ensureIndex({name:1}) create index on name db.people.find({name:“bob"}).explain() explain plan step
- 6. Query Optimization db.people.find({x:10,y:”foo”}) Collection people DiskLocation Scan Index on x Index Scan Index on y Index Scan
- 7. MongoDB Architecture Source: mongoDB Replication and Replica Set by Dwight Merriman 10gen
- 8. MongoDB Sharding MongoDB usestwo key operations to facilitate sharding - split and migrate. Split splits a chunk into two ranges; it is done to assure no one chunk is unusually large. Migrate moves a chunk (the data associated with a key range) to another shard. This is done as needed to rebalance. Split is an inexpensive metadata operation, while migrate is expensive as large amounts of data may be moving server to server. Both splits and migrates are performed automatically. MongoDB has a sub-system called Balancer, which monitors shards loads and moves chunks around if it finds an imbalance. If you add a new shard to the system, some chunks will eventually be moved to that shard to spread out the load. A recently split chunk may be moved immediately to a new shard if the system predicts that future insertions will benefit from that move.
- 9.
- 10. MongoDB Sharding: Briefly Sequence FROM:C TO:N #Make sure my view is complete and lock #Get the document’s DiskLoc for sharding #Trigger the N to sharding in Pull mode #Copy Index Definition from C #Remove existing data in [min~max] #Clone the data in[min~max] from C #Ask C to replicate the changes #Ask N to commit #N commit
- 11. MongoDB Sharding: InDetails FROM TO Notice: The FROM can be updated/deleted during sharding and TO can catch up in step 4.
- 12. Replication and Sharding Source:http://www.mongodb.org/display/DOCS/Simple+Initial+Sharding+Architecture
- 13. MongoDB Replication: Pullmode Slave continuously pull the OpLog from Master.
- 14. Question Reference: 1: Source codedigest: http://www.cnblogs.com/daizhj/category/260889.html 2: Books http://www.mongodb.org/display/DOCS/Books 3: MongoDB offical website http://www.mongodb.com/