Questions tagged [mongodb]

All versions of MongoDB - a scalable, high-performance, open source, document-oriented database.

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6
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1answer
2k views

what is mongodb telling me when it logs an update?

After several minutes of a large program that pushes a lot of data into mongo, my log starts to show a message for (I guess) each update. This seems awfully noisy, is there some special reason it ...
2
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2answers
1k views

Schema design for privacy settings in MongoDB

I have a set of documents that can have various privacy settings around them: They can be completed public (any registered user) can view them They can be viewable only by people following you (this "...
0
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1answer
78 views

How to save mongodb data sub data more properly in this case?

I have a business collection. The businesses are reviewed by users. Each user can only review a business once. Future reviews will simply replace the former one. This is how we store it: "Reviews"...
3
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1answer
6k views

Storing dictionaries in mongo

Is there any reliable and fast database architecture that allows to store a dictionary(containing up to hundred thousand words) using mongodb?
9
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1answer
7k views

MongoDB Not Using All Available RAM

I have something around 200 GB worth data stored in a mongo cluster. The physical memory on one of the instances which runs mongo is 8GB. Nothing else of any consequence runs on this instance. As near ...
1
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2answers
650 views

Mongodb multikey index and $all in queries

I have such structure of documents in my products collection: { title: 'Samsung Galaxy S III', category_id: ObjectId("50bcc2f0b910a6c1936a4424"), properties: [ { title: 'OS', ...
3
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1answer
2k views

MongoDB geospatial query with sort - performance issues

I have query (which is very slow ~2,5s): db.markers.find({ latlng: { '$within': { '$box': [ [ -16, -140 ], [ 75, 140 ] ] } } }).sort({_id: -1}).limit(1000) When I run explain for this query I get { ...
1
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1answer
201 views

Sharded Mongodb Communication

I would like to know what ports I need have open for a sharded mongodb cluster. For example does the mongos need to be able to accapt connections to and from mongoc. I dont want to have to many open ...
0
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1answer
4k views

RegEx bug in MongoDB

I run the following queries on a collection that have a lot of entries that contain [ and ]. db.test.find({word:/[\[]/}); // could not be run in console db.test.find({word:/\[/ }); ...
1
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1answer
2k views

How to interpret this “db.explain()” for this mongodb query

db.tablebusiness.find({ "LongitudeLatitude" : { "$within" : { "$centerSphere" : [[106.772835, -6.186753], 0.0089967464101566] } }, "indexContents" : { "$all" : ["warung"] }, "Prominent" : { "$gte" : ...
4
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2answers
2k views

mongoDB rs.initiate hangs

I am having trouble setting up replication on a new mongoDB installation. Everything works fine when I run without replication but when I run mongod with the --replSet option, and run rs.initiate(), ...
2
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2answers
427 views

Sharded MongoDB backup solution

I am looking for a way that I can backup my 12 MongoDB shards into a single server. Disk space is not an issue but getting the backups to be on a single node would be the best. I am not sure if there ...
0
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1answer
62 views

Why $in is much faster then $all

I am well aware of what those 2 do. $in take .3 seconds. And $all take 26 seconds. Huge different. If anything $in should take longer because it returns more data. Also if the limit is removed, $in ...
2
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1answer
2k views

Preserving whitespace in MongoDB values

In a simple scenario of me inserting a key-value pair, when value contains some white space, how can I preserve it? Example: > > db.bar.insert({"name":"mike "}) > > db.bar.find() { "...
2
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1answer
5k views

Can't start mongodb in ArchLinux

I have installed mongodb using sudo pacman -S mongodb in my 32-bit arch . At first I run this sudo mkdir -p /data/db to create /data/db ,and then run $ mongod ,then I got the following message : ...
0
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1answer
596 views

Moving a collection to a new database (v2.2)

To take advantage of the improved concurrency in Mongodb 2.2--namely database level locking--we would like to move a sharded collection to a new database. I have been unable to find any documentation ...
2
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1answer
175 views

Riak in SasS application

I am thinking about using Riak for a SasS application I started working on recently. I was originally thinking about MongoDB but after running into Riak it seems like it may be the better option. The ...
2
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1answer
4k views

Error “cannot connect to server” installing MongoDB on Ubuntu

I'm trying to install MongoDB on Ubuntu 10.04. I followed these installation instructions. I got the following error: Error: couldn't connect to server 127.0.0.1:27017 src/mongo/shell/mongo.js:91 ...
1
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1answer
3k views

$nearSphere returns too many data. What am I missing? Am I wrong? Is it a bug? Does other see the same thing?

I noticed that $near and $nearSphere returns completely different data and I got suspicious. After all, when latitude is near equator it sphere distance shouldn't differ a lot from euclidean distance. ...
0
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1answer
99 views

Why searching with $all in Mongodb is FAR SLOWER than the EQUIVALENT search?

$all with only one item is equivalent with normal search right? Here is the log without $all (I used 4700 test cases with 30 thread): Thu Sep 20 17:27:05 [conn11] query newisikotagte15.tablebusiness ...
6
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1answer
2k views

MongoDB - handling embedded documents and relations

I am researching MongoDB for a web app that I am bulding. Coming from a MySQL background, the concept of embedded documents is not so easy to fully understand. Let's say I have a document called ...
0
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1answer
119 views

Is Index Used for This Query

If so, which one? How do we know? I have 3 indexes in a query. Actually only the first 2 should be useful { "v": NumberInt(1), "key": { "LongitudeLatitude": "2d", "Prominent"▼: ...
5
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2answers
15k views

Error: couldn't connect to server 127.0.0.1:27017 src/mongo/shell/mongo.js:91 when changing mongodb data directory

I already change the owner of the directory I want to use root@ip-10-138-30-205:/media/newdrive# ls -l ...
3
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2answers
678 views

Does MongoDB auto compacting

I copy a collection to another collection. Data is 14GB. I deleted the copied collection. Yet the size of the directory is still 14 GB. I chose repair but it seems to take forever. Actually inserting ...
1
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1answer
513 views

What's the fastest way to replicate data?

I have a mongodb database data on my computer. I want to upload that into amazon.com server. The bottle neck is the internet connection. One way is to zip the file and then upload it to the server. ...
4
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2answers
25k views

How can I time-stamp data in MongoDB?

I'm responsible for writing an app to juggle a huge amount of client and business intelligence information. This information involves records for various businesses and metrics like revenue, their web ...
2
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1answer
1k views

How to add spatial indexes through rockmongo

In rockmongo we got fields for the field name and whether we should sort by ascending or descending. How to add spatial indexes then?
4
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1answer
730 views

Ideal environment and cost for running a medium size MongoDb server

I know some people will say this question does not belong here but i didnt find a better place on the internet to ask this. Please migrate to an appropriate place if you think it should be. I am using ...
4
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1answer
1k views

MongoDB optimization on high data

I have a mongoDB collection with 42M registers with 1M new registers every day. We found a low performance on mongoDB querying. showing in mongostat the fields: qr|qw ar|aw with values of 300-500. ...
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2answers
679 views

MongoDB replication to one machine

Does MonogDB supports replication where I have many machines with MongoDB that have different data and I want to replicate this data to one, and only one MongoDB?
1
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1answer
1k views

mongodb: replica-set processing reads on the primary

Running a replica-set with 1 primary and 2 secondaries, I wonder why the READs are also done on the primary. Shouldn't the primary mainly do the WRITEs and the secondary can share the READ-load?! I ...
1
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1answer
125 views

How can I automate sharding in the presence of continuous reads

I am using a pymongo in a sharded mongo environment. I have some fairly write-intensive systems, so I split the data up by time, with one database per hour, so the heavy-lifting of index-updates can ...
0
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1answer
98 views

MongoDB: Can I perform a second query if the first doesn't match

When querying MongoDB is it possible to perform a query and if it isn't matched perform a second query. I could perform an $or which will do booth queries and return the results for booth but I only ...
3
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1answer
424 views

Does mongodb automatically move small non-partitoned databases to spread read load?

I have a few hundred small databases, each between 0.2GB and 4.0GB in size. These are sitting on a sharded mongodb environment with 10 or so shards. At any one time, only a very small subset of these ...
1
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1answer
168 views

Storing all data in a single db versus multiple dbs in Mongodb

We have an app that is basically an ERP. Some of the resources in the ERP are satellite tracked. So the information related to the resource itself is minimal, but the satellite tracker produces data ...
-1
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1answer
209 views

What database do most mobile start ups use? [closed]

mongodb? MySQL? PostgreSQL? If someone would add pluses and minus, let me know. Why I ask: I am a mobile startup. I need a database that supports spatial indexes. The spatial index must be able to ...
6
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1answer
1k views

MongoDB deployment best practices

I had a few questions around deployment best practices and how folks are using mongodb today. Feel free to add any other comments you can think off. No of databases per mongod instance. Is the ...
3
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1answer
678 views

Could a large log file be the reason cron job keeps dying?

The log is 15 Gigabytes. I guess I have to back it up and delete. I have enough hard disc space, but did not realize log was so large. And overnight cron jobs suddenly started to die in the middle.
1
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1answer
132 views

Where do caching servers conceptually fit in my architecture?

Given the simple well-known architecture below: Where (conceptually) does the caching server(s) sit?
5
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1answer
713 views

MongoDB working set size on capped collection larger than capped collection size?

On my database server right now I have 16GB of ram and an 8GB capped collection with about 4GB of indexes. So I may understand this wrong but shouldn't this only ever use around 12GB of my RAM or ...
1
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1answer
114 views

Transfering data from one MongoDB server to another while eliminating users/authentication

I am transferring MongoDB databases from one server to another. The servers cannot talk to each other, so I must use mongodump/mongorestore. The 'from' server used authentication for the databases. ...
7
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1answer
2k views

What factors contribute to lock-percentage with MongoDB

We're attempting to better optimize how we're using our MongoDB instance. We seem to be routinely getting high lock-percentages, and are looking to help minimize that. Here is some mongostat output: ...
7
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1answer
1k views

How to store and query products the price of which depends on a complex set of conditions?

I haven't decided on a database. I have expirience with MySQl and I'm intrigued by MongoDB. Let the products be packages of cable tv providers: { name: "Virgin TV", price: 20 }, { ...
0
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1answer
191 views

The sort column must be the last column used in the index - MongoDB Indexing Advice

MongoDB docs advices that: The sort column must be the last column used in the index Here is the example: db.foo.ensureIndex({a: 1, b: 1, c: 1}) Good: find(a=1).sort(a) find(a=1).sort(b) find(a=...
6
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3answers
2k views

Setting up Mongo with clustering

I'm going to start using Mongo as a database but I will not have it clustered at first. Can I use Mongo on a single machine, then later come back, cluster it and capitalize on the sharding? Or can I ...
7
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1answer
2k views

Mongo Map-Reduce or Sharding?

So I asked this question: Setting up Mongo with clustering But I didn't know enough until I read the answers and did more research. Is it better to use Map-reduce or sharding for fast-paced ...
16
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1answer
4k views

How do databases store index key values (on-disk) for variable length fields?

Context This question pertains to the low-level implementation details of indexes in both SQL and NoSQL database systems. Actual structure of the index (B+ tree, hash, SSTable, etc.) is irrelevant as ...
4
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1answer
1k views

Would appreciate some suggestions on how I should model this data

I am setting up a website that will have users. Users can search for songs and (if signed in) save them to a playlist or their library of songs. I want it to be like iTunes in that all the songs on ...
6
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1answer
3k views

In MongoDB, is having lots of small collections better than having one huge collection?

Huge collections have huge indexes that may not fit into RAM. Is that problem entirely solved with sharding ? If I have lots of small collections with small indexes, what are the options for storing ...
3
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2answers
193 views

What are the best Database Analytics Companies for analyzing several 1000s or Mio. of products,sum them together and analyze them for statistics?

We will get several thousands products in our database. The problem is that one product can have several different names e.g. "iPad 16GByte UMTS schwarz" or "iPad 16GB 3G black" and so on. But they ...