![Data Model: Document oriented
{
_id:
1,
name:
{
first:
'Michael',
last:
'Faraday'
},
birth:
new
Date('Sep
22,
1791'),
death:
new
Date('Aug
25,
1867'),
contribs:
['Chemistry',
'Electricity',
'Diamagnetism']
}](https://image.slidesharecdn.com/howmongodbworks-130201054641-phpapp01/85/How-MongoDB-works-3-320.jpg)
Uploaded byVladimir Miguro
How MongoDB works
This document summarizes how MongoDB works. It discusses MongoDB's document-oriented data model using JSON-like documents and BSON format. It covers reading and querying data dynamically using conditions and projections, as well as indexing to optimize queries. Writing data with different write concerns for reliability is also summarized. Other sections discuss storage layout and memory mapping, as well as scaling MongoDB through replication and sharding across multiple nodes.
How MongoDB works
- 1. How MongoDB works UladzimirMihura Senior Software Engineer, EPAM Systems Software Engineering Conference 2013
- 2.
- 3. Data Model: Documentoriented { _id: 1, name: { first: 'Michael', last: 'Faraday' }, birth: new Date('Sep 22, 1791'), death: new Date('Aug 25, 1867'), contribs: ['Chemistry', 'Electricity', 'Diamagnetism'] }
- 4. Data Model: BSON { hello: 'SEC 2013'} x19x00x00x00 x02hello x09x00x00x00 SEC 2013x00
- 5. Data Model: Structure Document Collection Database MongoDB Instance
- 6.
- 7. Reading: Dynamic Queries • find, findOne • accepts a conditions object • regex, strings, numbers, etc... • rich operators • $lt, $gt, $or, $and, $in, $ne, ... • projections • specify fields to return
- 8. Reading: Indexes • B-Tree •multiply fields Di Lu Rh • options Zo Sa Cr St B C • unique • Ka sparse Cr H B C • 2d F • full text search (≥2.4)
- 9. Reading: Query Optimizer db.foo.find({ x: 10, y:'bar'}) full scan x index on x x index on y remember
- 10.
- 11. Writing: Write Concerns •Errors ignored (even network errors) • Unacknowledged (fire & forget) • Acknowledged (write accepted) • Journaled • Propagated to the replica set members
- 12. Writing: Isolation db.foo.update( { field1 : 1 , $isolated : 1 }, { $inc : { field2 : 1 } } , { multi: true } )
- 13.
- 14. Storage: Padding factor ... Padding Header BSON Data Padding Header ...
- 15. Storage: Directory Layout -‐rw-‐-‐-‐-‐-‐-‐-‐ 1 trnl trnl 64M Jan 28 14:38 foo.0 -‐rw-‐-‐-‐-‐-‐-‐-‐ 1 trnl trnl 128M Jan 28 14:26 foo.1 -‐rw-‐-‐-‐-‐-‐-‐-‐ 1 trnl trnl 256M Jan 28 14:31 foo.2 -‐rw-‐-‐-‐-‐-‐-‐-‐ 1 trnl trnl 512M Jan 28 14:38 foo.3 -‐rw-‐-‐-‐-‐-‐-‐-‐ 1 trnl trnl 1.0G Jan 28 14:38 foo.4 -‐rw-‐-‐-‐-‐-‐-‐-‐ 1 trnl trnl 2.0G Jan 28 14:38 foo.5 -‐rw-‐-‐-‐-‐-‐-‐-‐ 1 trnl trnl 16M Jan 28 14:38 foo.ns • Separate files per database • Aggressive preallocation
- 16. Storage: Memory mappedfiles Virtual Memory foo.1 foo.2 foo.3 ... foo.n
- 17.
- 18. Scaling: Replication Node 1 Node 2 Secondary Secondary read Node 3 read Replication Primary Replication read write client
- 19. Scaling: Replication Replication Node 1 Node 2 Primary Secondary read write Node 3 read Primary client
- 20. Scaling: Replication Replication Node 1 Node 2 Primary Secondary Replication read write Node 3 read Secondary read client
- 21. Scaling: Sharding Config Client Servers mongod mongos mongos ... mongod mongod Replica Set Replica Set Replica Set mongod mongod mongod mongod mongod mongod mongod mongod mongod Shards
- 22. MongoDB Drivers Team@ 10gen
- 23. Hosted Solutions • MongoLab.com •MongoHQ.com • HostedMongo.com • MongoMachine.com • ObjectRocket • etc
- 24. http://try.mongodb.org/ http://on.fb.me/bymongo/ Thank you. Let’s ask.