MongoDB: Replication,Sharding,MapReduce
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The document shows examples of queries that can be performed on a MongoDB collection, including finding documents by field values, regular expressions, and querying embedded documents, as well as update operations like setting values, incrementing values, pulling from arrays, and adding to arrays. It also provides examples of MapReduce operations in MongoDB and using finalize functions.
![{
"_id" : ObjectId("4dcd3ebc9278000000005158"),
"timestamp" : ISODate("2011-05-13T14:22:46.777Z"),
"binary" : BinData(0,""),
"string" : "abc",
"number" : 3,
"subobj" : {"subA": 1, "subB": 2 },
"array" : [1, 2, 3],
"dbref" : [_id1, _id2, _id3]
padding
}](https://image.slidesharecdn.com/mongodist-110708000653-phpapp01/85/MongoDB-Replication-Sharding-MapReduce-9-320.jpg)
![{ db.coll.find({"string": "abc"});
db.coll.find({ "string" : /^a.*$/i });
"_id" : ObjectId("4dcd3ebc9278000000005158"),
"timestamp" : ISODate("2011-05-13T14:22:46.777Z"),
db.coll.find({"subobj.subA": 1});
db.coll.find({"subobj.subB": {$exists: true} });
"binary" : BinData(0,""),
"string" : "abc", db.coll.find({"number": 3});
db.coll.find({"number": {$gt: 1}});
"number" : 3,
"subobj" : {"subA": 1, "subB": 2 },
"array" : [1, 2, 3],
db.coll.find({"array": {$all:[1, 2]} });
"dbref" : [_id1, _id2, _id3]
db.coll.find({"array": {$in:[2, 4, 6]} });
padding
}](https://image.slidesharecdn.com/mongodist-110708000653-phpapp01/85/MongoDB-Replication-Sharding-MapReduce-10-320.jpg)
![{
"_id" : ObjectId("4dcd3ebc9278000000005158"),
"timestamp" : ISODate("2011-05-13T14:22:46.777Z"),
{ $set : {"string": "def"} }
"binary" : BinData(0,""), { $inc : {"number": 1} }
"string" : "def",
{ $pull : {"subobj": {"subB": 2 } } }
"number" : 4,
"subobj" : {"subA": 1, "subB": 2 },
"array" : [1, 2, 3, 4, 5, 6],
"dbref"$addToSet : { "array" : { $each : [ 4 , 5 , 6 ] } } }
{ : [_id1, _id2, _id3]
"newkey" : "In-place"
} { $set : {"newkey": "In-place"} }](https://image.slidesharecdn.com/mongodist-110708000653-phpapp01/85/MongoDB-Replication-Sharding-MapReduce-11-320.jpg)
![m = function(){
this.tags.forEach{
function(z) {
emit(z, {count: 1});
}
};
};
r = function(key, values) {
var total=0;
for (i=0, i<values.length, i++)
total += values[i].count;
return { count : total };
}
res=db.things.mapReduce(m,!r);
# finalize](https://image.slidesharecdn.com/mongodist-110708000653-phpapp01/85/MongoDB-Replication-Sharding-MapReduce-34-320.jpg)
MongoDB: Replication,Sharding,MapReduce
- 9. { "_id" : ObjectId("4dcd3ebc9278000000005158"), "timestamp" : ISODate("2011-05-13T14:22:46.777Z"), "binary" : BinData(0,""), "string" : "abc", "number" : 3, "subobj" : {"subA": 1, "subB": 2 }, "array" : [1, 2, 3], "dbref" : [_id1, _id2, _id3] padding }
- 10. { db.coll.find({"string": "abc"}); db.coll.find({ "string" : /^a.*$/i }); "_id" : ObjectId("4dcd3ebc9278000000005158"), "timestamp" : ISODate("2011-05-13T14:22:46.777Z"), db.coll.find({"subobj.subA": 1}); db.coll.find({"subobj.subB": {$exists: true} }); "binary" : BinData(0,""), "string" : "abc", db.coll.find({"number": 3}); db.coll.find({"number": {$gt: 1}}); "number" : 3, "subobj" : {"subA": 1, "subB": 2 }, "array" : [1, 2, 3], db.coll.find({"array": {$all:[1, 2]} }); "dbref" : [_id1, _id2, _id3] db.coll.find({"array": {$in:[2, 4, 6]} }); padding }
- 11. { "_id" : ObjectId("4dcd3ebc9278000000005158"), "timestamp" : ISODate("2011-05-13T14:22:46.777Z"), { $set : {"string": "def"} } "binary" : BinData(0,""), { $inc : {"number": 1} } "string" : "def", { $pull : {"subobj": {"subB": 2 } } } "number" : 4, "subobj" : {"subA": 1, "subB": 2 }, "array" : [1, 2, 3, 4, 5, 6], "dbref"$addToSet : { "array" : { $each : [ 4 , 5 , 6 ] } } } { : [_id1, _id2, _id3] "newkey" : "In-place" } { $set : {"newkey": "In-place"} }
- 14. Member1 Member2 Primary Secondary Member4 Member3 Secondary Secondary
- 15. Member1 Member2 Primary Secondary Member4 Member3 Secondary Secondary
- 16. Member1 Member2 Primary Secondary Member4 Member3 Secondary Secondary
- 17. Member2 Secondary Member4 Member3 Secondary Secondary
- 18. Member1 Primary Member6 Member2 Secondary Secondary Member5 Member3 Secondary Secondary Member4 Secondary
- 19. Member1 Primary Member6 Member2 Secondary Secondary Member5 Member3 Secondary Secondary Member4 Secondary
- 20. Member1 Primary Member6 Member2 Secondary Secondary Member5 Member3 Secondary Secondary Member4 Secondary
- 24. Chunk Shard Key Chunk 200MB
- 25. Cluster Shard Servers (Data) config Servers (Shard Configration) shard1 shard2 shard3 [ a, f ) [ k, n) [ o, t ) Chunk [ f, k ) [ n, o ) [ t, } ) mongos Servers (Routers)
- 27. primary Shard primary 1 ( mongos primary primary primary ) Shard cinfig Shard mongos http://www.mongodb.org/display/DOCS/Introduction
- 28. shard1 shard2 [ a, f ) [ n, o ) [ o, t) [ 0, 9) [ f, k ) [ k, n) shard1 shard2 [ a, f ) [ o, t) [ n, o ) [ f, k ) [ k, n) [ 0, 9)
- 34. m = function(){ this.tags.forEach{ function(z) { emit(z, {count: 1}); } }; }; r = function(key, values) { var total=0; for (i=0, i<values.length, i++) total += values[i].count; return { count : total }; } res=db.things.mapReduce(m,!r); # finalize