MongoDB @ Frankfurt NoSql User Group
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This document provides an overview of MongoDB and how it compares to traditional RDBMS systems. It discusses key concepts like how MongoDB uses JSON-like documents with flexible schemas rather than rigid tables. It also covers CRUD operations, indexing, replication, and how data is stored and queries in MongoDB compared to SQL.
![Flexible “Schemas”
{ “author”: “brendan”,
“text”: “...” }
{ “author”: “brendan”,
“text”: “...”,
“tags”: [“mongodb”,
“nosql”] }
Wednesday, 22 February 12](https://image.slidesharecdn.com/mongodb-frankfurt-nosql-user-group-120222162618-phpapp02/85/MongoDB-Frankfurt-NoSql-User-Group-6-320.jpg)
![The Same Data in MongoDB
{
"_id" : ObjectId("4dfa6baa9c65dae09a4bbda5"),
"title" : "Programming in Scala",
"author" : [
{
"first_name" : "Martin",
"last_name" : "Odersky",
"nationality" : "DE",
"year_of_birth" : 1958
},
{
"first_name" : "Lex",
"last_name" : "Spoon"
},
{
"first_name" : "Bill",
"last_name" : "Venners"
}
]
}
Wednesday, 22 February 12](https://image.slidesharecdn.com/mongodb-frankfurt-nosql-user-group-120222162618-phpapp02/85/MongoDB-Frankfurt-NoSql-User-Group-7-320.jpg)
![Indexing Embedded Arrays
db.blogs.save({
title: "My First blog",
comments: [
{author: "James", ts : new Date()} ]
});
db.blogs.ensureIndex({"comments.author": 1})
db.blogs.find({"comments.author": "James"})
Wednesday, 22 February 12](https://image.slidesharecdn.com/mongodb-frankfurt-nosql-user-group-120222162618-phpapp02/85/MongoDB-Frankfurt-NoSql-User-Group-16-320.jpg)
![Multikeys
db.blogs.save({
title: "My Second blog",
tags: ["mongodb", "NoSQL"]
});
db.blogs.ensureIndex({tags: 1})
db.blogs.find({tags: "NoSQL"})
Wednesday, 22 February 12](https://image.slidesharecdn.com/mongodb-frankfurt-nosql-user-group-120222162618-phpapp02/85/MongoDB-Frankfurt-NoSql-User-Group-17-320.jpg)
![Geospatial
• Geo hash stored in B-Tree
• First two values indexed
db.blogs.save({
loc: { long: 40.739037, lat: 40.739037 }
});
db.blogs.save({
loc: [40.739037, 40.739037]
});
db.blogs.ensureIndex({"loc": "2d"})
Wednesday, 22 February 12](https://image.slidesharecdn.com/mongodb-frankfurt-nosql-user-group-120222162618-phpapp02/85/MongoDB-Frankfurt-NoSql-User-Group-20-320.jpg)
MongoDB @ Frankfurt NoSql User Group
- 1. Frankfurt NoSQL User Group Chris Harris Email : charris@10gen.com Twitter : cj_harris5 Wednesday, 22 February 12
- 2. As simple as possible, but no simpler Memcached Key / Value Scalability & Performance RDBMS Depth of functionality Wednesday, 22 February 12
- 3. Key/Value Store MongoDB Relational Database Wednesday, 22 February 12
- 4. Terminology RDBMS MongoDB Table Collection Row(s) JSON Document Index Index Join Embedding & Linking Partition Shard Partition Key Shard Key Wednesday, 22 February 12
- 5. Here is a “simple” SQL Model mysql> select * from book; +----+----------------------------------------------------------+ | id | title | +----+----------------------------------------------------------+ | 1 | The Demon-Haunted World: Science as a Candle in the Dark | | 2 | Cosmos | | 3 | Programming in Scala | +----+----------------------------------------------------------+ 3 rows in set (0.00 sec) mysql> select * from bookauthor; +---------+-----------+ | book_id | author_id | +---------+-----------+ | 1| 1| | 2| 1| | 3| 2| | 3| 3| | 3| 4| +---------+-----------+ 5 rows in set (0.00 sec) mysql> select * from author; +----+-----------+------------+-------------+-------------+---------------+ | id | last_name | first_name | middle_name | nationality | year_of_birth | +----+-----------+------------+-------------+-------------+---------------+ | 1 | Sagan | Carl | Edward | NULL | 1934 | | 2 | Odersky | Martin | NULL | DE | 1958 | | 3 | Spoon | Lex | NULL | NULL | NULL | | 4 | Venners | Bill | NULL | NULL | NULL | +----+-----------+------------+-------------+-------------+---------------+ 4 rows in set (0.00 sec) Wednesday, 22 February 12
- 6. Flexible “Schemas” { “author”: “brendan”, “text”: “...” } { “author”: “brendan”, “text”: “...”, “tags”: [“mongodb”, “nosql”] } Wednesday, 22 February 12
- 7. The Same Data in MongoDB { "_id" : ObjectId("4dfa6baa9c65dae09a4bbda5"), "title" : "Programming in Scala", "author" : [ { "first_name" : "Martin", "last_name" : "Odersky", "nationality" : "DE", "year_of_birth" : 1958 }, { "first_name" : "Lex", "last_name" : "Spoon" }, { "first_name" : "Bill", "last_name" : "Venners" } ] } Wednesday, 22 February 12
- 8. CRUD Operations Wednesday, 22 February 12
- 9. db.test.insert({fn: “Chris”, ln: “Harris”}) Wednesday, 22 February 12
- 10. db.test.find({fn: “Chris”}) Wednesday, 22 February 12
- 11. Cursors $gt, $lt, $gte, $lte, $ne, $all, $in, $nin, $or, $not, $mod, $size, $exists, $type, $elemMatch > var c = db.test.find({x: 20}).skip(20).limit(10)> c.next() > c.next() ... query first N results + cursor id getMore w/ cursor id next N results + cursor id or 0 ... Wednesday, 22 February 12
- 12. Creating Indexes An index on _id is automatic. For more use ensureIndex: db.blogs.ensureIndex({author: 1}) 1 = ascending -1 = descending Wednesday, 22 February 12
- 13. Compound Indexes db.blogs.save({ author: "James", ts: new Date() ... }); db.blogs.ensureIndex({author: 1, ts: -1}) Wednesday, 22 February 12
- 14. Unique Indexes db.blogs.save({ author: "James", title: "My first blog" ... }); db.blogs.ensureIndex({title: 1}, {unique: true}) Wednesday, 22 February 12
- 15. Indexing Embedded Documents db.blogs.save({ title: "My First blog", stats : { views: 0, followers: 0 } }); db.blogs.ensureIndex({"stats.followers": -1}) db.blogs.find({"stats.followers": {$gt: 500}}) Wednesday, 22 February 12
- 16. Indexing Embedded Arrays db.blogs.save({ title: "My First blog", comments: [ {author: "James", ts : new Date()} ] }); db.blogs.ensureIndex({"comments.author": 1}) db.blogs.find({"comments.author": "James"}) Wednesday, 22 February 12
- 17. Multikeys db.blogs.save({ title: "My Second blog", tags: ["mongodb", "NoSQL"] }); db.blogs.ensureIndex({tags: 1}) db.blogs.find({tags: "NoSQL"}) Wednesday, 22 February 12
- 18. Covered Indexes • From 1.8.0 • Query resolved in index only • Need to exclude _id from items projected db.blogs.save({ author: "James", title: "My first blog" }); db.blogs.ensureIndex({author: 1}) db.blogs.find({author: "James"}, {author: 1, _id:0})) Wednesday, 22 February 12
- 19. Sparse Indexes • From 1.8.0 • Key value included if and only if the value is present • Reduces size of index • Limited to a single field db.blogs.ensureIndex({loc: 1}, {sparse: true}) // loc key stored for Ben & Sarah only db.blogs.save({author: "Jim"}) db.blogs.save({author: "Ben", loc: null}) db.blogs.save({author: "Sarah", loc: "CA"}) Wednesday, 22 February 12
- 20. Geospatial • Geo hash stored in B-Tree • First two values indexed db.blogs.save({ loc: { long: 40.739037, lat: 40.739037 } }); db.blogs.save({ loc: [40.739037, 40.739037] }); db.blogs.ensureIndex({"loc": "2d"}) Wednesday, 22 February 12
- 22. Types of outage • Planned • Hardware upgrade • O/S or file-system tuning • Relocation of data to new file-system / storage • Software upgrade • Unplanned • Hardware failure • Data center failure • Region outage • Human error • Application corruption Wednesday, 22 February 12
- 23. Replica Set features • A cluster of N servers • Any (one) node can be primary • Consensus election of primary • Automatic failover • Automatic recovery • All writes to primary • Reads can be to primary (default) or a secondary Wednesday, 22 February 12
- 24. How MongoDB Replication works Member 1 Member 3 Member 2 •Set is made up of 2 or more nodes Wednesday, 22 February 12
- 25. How MongoDB Replication works Member 1 Member 3 Member 2 PRIMARY •Election establishes the PRIMARY •Data replication from PRIMARY to SECONDARY Wednesday, 22 February 12
- 26. How MongoDB Replication works negotiate new master Member 1 Member 3 Member 2 DOWN •PRIMARY may fail •Automatic election of new PRIMARY if majority exists Wednesday, 22 February 12
- 27. How MongoDB Replication works Member 1 Member 3 PRIMARY Member 2 DOWN •New PRIMARY elected •Replication Set re-established Wednesday, 22 February 12
- 28. How MongoDB Replication works Member 1 Member 3 PRIMARY Member 2 RECOVERING •Automatic recovery Wednesday, 22 February 12
- 29. How MongoDB Replication works Member 1 Member 3 PRIMARY Member 2 •Replication Set re-established Wednesday, 22 February 12
- 31. http://community.qlikview.com/cfs-filesystemfile.ashx/__key/CommunityServer.Blogs.Components.WeblogFiles/ theqlikviewblog/Cutting-Grass-with-Scissors-_2D00_-2.jpg Wednesday, 22 February 12
- 33. MongoDB Scaling - Single Node read node_a1 write Wednesday, 22 February 12
- 34. Write scaling - add Shards read shard1 shard2 node_c1 node_c2 node_b1 node_b2 node_a1 node_a2 write Wednesday, 22 February 12
- 35. Write scaling - add Shards read shard1 shard2 shard3 node_c1 node_c2 node_c3 node_b1 node_b2 node_b3 node_a1 node_a2 node_a3 write Wednesday, 22 February 12
- 36. MongoDB Sharding • Automatic partitioning and management • Range based • Convert to sharded system with no downtime • Fully consistent Wednesday, 22 February 12
- 37. How MongoDB Sharding works > db.posts.save( {age:40} ) -∞ +∞ -∞ 40 41 +∞ •Data in inserted •Ranges are split into more “chunks” Wednesday, 22 February 12
- 38. How MongoDB Sharding works > db.posts.save( {age:40} ) > db.posts.save( {age:50} ) -∞ +∞ -∞ 40 41 +∞ 41 50 51 +∞ •More Data in inserted •Ranges are split into more“chunks” Wednesday, 22 February 12
- 39. How MongoDB Sharding works > db.posts.save( {age:40} ) > db.posts.save( {age:50} ) > db.posts.save( {age:60} ) -∞ +∞ -∞ 40 41 +∞ 41 50 51 +∞ 51 60 61 +∞ Wednesday, 22 February 12
- 40. Balancing mongos config balancer config Chunks! config 1 2 3 4 13 14 15 16 25 26 27 28 37 38 39 40 5 6 7 8 17 18 19 20 29 30 31 32 41 42 43 44 9 10 11 12 21 22 23 24 33 34 35 36 45 46 47 48 Shard 1 Shard 2 Shard 3 Shard 4 Wednesday, 22 February 12
- 41. Balancing mongos config balancer config Imbalance Imbalance config 1 2 3 4 5 6 7 8 9 10 11 12 21 22 23 24 33 34 35 36 45 46 47 48 Shard 1 Shard 2 Shard 3 Shard 4 Wednesday, 22 February 12
- 42. Balancing mongos config balancer config Move chunk 1 to config Shard 2 1 2 3 4 5 6 7 8 9 10 11 12 21 22 23 24 33 34 35 36 45 46 47 48 Shard 1 Shard 2 Shard 3 Shard 4 Wednesday, 22 February 12
- 43. Balancing mongos config balancer config config 1 2 3 4 5 6 7 8 9 10 11 12 21 22 23 24 33 34 35 36 45 46 47 48 Shard 1 Shard 2 Shard 3 Shard 4 Wednesday, 22 February 12
- 44. Balancing mongos config balancer config config 2 3 4 5 6 7 8 1 9 10 11 12 21 22 23 24 33 34 35 36 45 46 47 48 Shard 1 Shard 2 Shard 3 Shard 4 Wednesday, 22 February 12
- 45. Balancing mongos config balancer config Chunk 1 now lives on Shard 2 config 2 3 4 5 6 7 8 1 9 10 11 12 21 22 23 24 33 34 35 36 45 46 47 48 Shard 1 Shard 2 Shard 3 Shard 4 Wednesday, 22 February 12