MongoDB is a scalable, high-performance, open source, document-oriented database. It supports a large number of languages and application development platforms. Questions about programming should be asked on http://stackoverflow.com.

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4k views

How to limit the connections per host in MongoDB?

I'm running a mongo server which accepts connections from other clients through java driver. The thing I have noticed is after a while some users open too many ports, and this prevents other users to ...
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1answer
71 views

What folders should I check to see if these MongoDB applications are installed on my server?

I have a CentOS (Linux) server and looked at the /bin directory, but don't find the applications listed below. What folders should I check to see if these applications are installed on my server? I'm ...
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2answers
135 views

Is it always faster to create indexes after loading data?

I have a large number of records (~1 billion) that I need to load into MongoDB (actually TokuMX, but whatever). I have about 6 different indices I need to create on the collection. Is it always faster ...
2
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1answer
471 views

mongosniff is missing in mongo package

I installed mongodb-10gen version 2.4.6 in Debian. This package does not include mongosniff. How can I install a pre-built version of mongosniff in Debian ?
2
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1answer
929 views

How does MongoDB store data in RAM?

I'm trying to sift through the remains of an event that was causing us a lot troubles. Aside from report to management about what happened, I'm trying to gain a much better understanding of how this ...
2
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1answer
2k views

Can I disable journalling to improve performance

We have a 16 shard MongoDB 2.4 installation running in AWS that is eating money. The data is volatile, it only gets used within 15 minutes of creation If the cluster goes down we wipe it out and ...
2
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1answer
1k views

Mongo authentication user can't drop database

my question is - is it possible to define user in the Mongo database who will be able to drop the database? Maximum user privilege is "dbAdmin" but that privilege doesn't allow users to drop the ...
2
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1answer
145 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

mongodb: drop all collections

How to remove existing content before entering a replicaset the first time? mongodb worries about: ... has data already, cannot initiate set. All members except initiator must be empty.
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3answers
738 views

MongoDB does'nt starts after changing the data directory

I have installed a mongodb instance using yum..Now everything works fine.I started the service using service mongod start,it works good.Then i changed the data directory and log path in the ...
2
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1answer
1k views

how to upgrade the config servers to use WiredTiger in mongodb 3.0.0

I am reading the document upgrade config servers to use WiredTiger. In the section of "change config server to use WiredTiger", the second step is "stop the last config server listed in the mongos' ...
2
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1answer
232 views

Do MongoDB's “read uncommit” and “write lock” conflict with each other?

I was reading the MongoDB documentation, where it says about read uncommit: MongoDB allows clients to read documents inserted or modified before it commits these modifications to disk, regardless of ...
2
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1answer
777 views

MongoDB ReplicaSet reconfig when primary and majority don't exist

http://docs.mongodb.org/manual/tutorial/reconfigure-replica-set-with-unavailable-members/ Is there anyway to reconfigure a replica set in the event the primary as well as a majority of the servers ...
2
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1answer
379 views

mongodb: maxTimeMS ignored

After trying with different drivers and clients, we suffer with mongodb timeout on find query. Even Profiling logs the settings and issue well. 2014-08-13T23:46:43.218+0200 [conn80] query ...
2
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1answer
236 views

How do I add a user that has read access to only ONE database?

I have two databases admin and testdb ; Added a user Alice in the test database db.addUser( { user: "Alice",pwd: "Moon1234",roles: [ "readWrite" ] } ); But when I login using the user Alice, I can ...
2
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1answer
1k views

mongodb distinct() in an array

In my mongodb database,there is only one document below: { "_id" : ObjectId("5226efc5ccf23796f9590f67"), "count" : NumberLong(126045), "eissn" : "1466-5034", "grade" : 0.0, ...
2
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2answers
513 views

Can I run a mongos without any config servers?

I just want to use mongos as a tool to scale up the number of connections I can open to mongo. So can I run the mongos without any config servers? Has any one done this before?
2
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1answer
64 views

How to handle “or” possibilities in MongoDB

I'm new to MongoDB and by no means an expert in DB design in general. This feels like a really basic question that's probably been answered a million times, but I'm having a surprisingly hard time ...
2
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1answer
183 views

Which database to use? [closed]

Hey there. I am looking for a free to use for commercial website database that should have these design features, in the given order: Auto-Sharding (getting more free space by adding more server ...
2
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2answers
321 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 ...
2
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1answer
414 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() { ...
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1answer
2k 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?
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2answers
3k views

How to display query result in rockmongo by using execute method

I executed a command in mongo.exe > db.tablebusiness.find({"_id": "the-simmons-paradise__41.85_-87.88"}); I got results: Now I try similar command in rockmongo. If I execute ...
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1answer
14 views

mongorestore failure: error writing file “/var/lib/mongodb”

I want sync my server db with my local db; dump db mongodump --db [db name] copy dump folder into my local restore dump on my local mongorestore --db [db name] [dump folder path] I ...
2
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1answer
20 views

mongodb is using most of disk space for journal and not cleaning itself

I am using mongodb on production with journal enabled. I am using mongodb to store application data and also using gridfs to store images. I am using Elastic Block Storage (EBS) with 10GB for each ...
2
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1answer
110 views

Mongodb high lock percentage / slow queries

I'm working with an application using MongoDB that is getting a fairly large number of incoming requests and I've noticed that the responses are getting slower as the number of requests get higher. ...
2
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2answers
302 views

Mongos version 3.0.1 Split Chunk Error with Sharding

I have 3 config server and two shards. Each shard has a primary, secondary and an arbiter. This is running with the following mongod settings: storageEngine=wiredTiger ...
2
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1answer
647 views

When upgrading config servers to use WireTiger, the running config server with wiredtiger does not authenticate the existing pass and user?

In order to upgrade mongodb to 3.0.0, I am upgrading my config servers to use WireTiger. I followed the subsection of Change Config Server to Use WiredTiger. There are 18 steps. I run mongodump --port ...
2
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1answer
88 views

MongoDB - real disk usage is LOWER than dbStats.storageFile

I'm a bit surprised by what I observe in my mongo server, so I would like to know if anybody understand how this is possible. I have one collection of around 15K documents. For each of them, I store ...
2
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1answer
100 views

Mongodump on Replica Set

Running backups on a Mongo Replica set - 1 primary, 1 secondary, 1 arbitrar. Had a instance where all three stopped talking to one another and all went to secondary. I ran a backup against the the ...
2
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2answers
117 views

MongoDB replica sets and data duplication

I am new to MongoDB and trying to understand replica sets. Specifically, I am trying to understand how MongoDB would handle the following situation: A record is written to a table with a unique ...
2
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2answers
2k views

MongoDB YAML file problems on Windows

I managed to get MongoDB running as a three member replica on Windows 8, but I had problems with configuration files. If I used the new (MongoDB 2.6) file format (YAML) and used the replica set name ...
2
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1answer
1k views

MongoDB - Query elemMatch Date

Having a document structure like this: { "_id" : ObjectId("5359816b036493327d7cae95"), "_class" : "com.myproject.MyObjectDTO", "signals" : [ { "signalType" : "ABC", "quantity" : ...
2
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1answer
234 views

What are these files in MongoDB?

I was looking into my server and I found this: [root@host ~]# cd /var/lib/mongo/journal/ [root@host journal]# ls -lh total 3.1G -rw-------. 1 mongod mongod 1.0G Apr 7 01:18 j._0 -rw-------. 1 mongod ...
2
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1answer
695 views

SpringData MongoDB - infinite getmore on mongo logs

Doing 2 queries on MongoDB through Spring Data on around 160 000 rows, query 1 is executed in few seconds (about 20 results) but query 2 never finish. I'm getting this line over and over on mongodb ...
2
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1answer
784 views

Mongodb 2.6 Server crash and not restarting

We are using mongodb 2.6 with one Primary and 2 secondaries. One of the secondary has gone bad and not restarting. 2014-04-18T21:13:34.765+0000 [rsSync] replSet still syncing, not yet to minValid ...
2
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1answer
2k views

Can't take a write lock while out of disk space

Help me please! My C:\mongodb-win32-x86_64-2.4.6\data size is 8G. I have 95G free space of drive C. But I get this message: com.mongodb.WriteConcernException: { "serverUsed" : "/127.0.0.1:27017" ...
2
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1answer
460 views

Can arbiterOnly replica in MongoDB become SECONDARY and what it means?

The MongoDB documentation says that when a replica is added to the set as arbiterOnly=true it will not become Primary. But can Arbiter become a secondary and what does it when it does? I have a ...
2
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1answer
3k views

How to create an efficient, scalable, multi-tenant data layer using MongoDB? [closed]

I'm working on the architecture for my upcoming Project Mangement app (as an example) and I'm seeking clarity on how best to design the MongoDB data layer, with specific regard to multi-tenancy. The ...
2
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1answer
112 views

Start mongod instance on replica set as background job

I have setup a Mongodb replica set with 1 secondary node. When i execute on secondary sudo mongod --replSet rs0 --dbpath /data --port 27017 --oplogSize 700 The primary and secondary nodes are ...
2
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1answer
838 views

How much free space do I need for mongoDB? and how to reclaim lost space?

I ran out of disk space on my mongo database. I saw it and dropped some collections (120 out of 1700 i had). And ran db.compact(...) thinking it would release free space. well, that was a stupid idea. ...
2
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1answer
524 views

How to setup a MongoDB replica set for the connector

I want to keep MongoDB and Solr in sync. The mongodb-connector (python) is the tool I want to use to do that. Now a replica set in mongodb is required (see ReadMe), but I don't want (and can) setup a ...
2
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1answer
160 views

Improving concurrency in MongoDB via sharding

Our current setup: Cluster of ~500 ec2 c1.xLarge worker nodes with 8 threads on each running scientific simulations Results temporarily stored at runtime on each worker node's local MongoDB, using ...
2
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1answer
854 views

MongoDB: move documents before capping

The cappedCollection concept works well for most of my projects where cleaning old data without care makes sense. For another projects, I need a more complex and safe concept. The requirement is ...
2
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1answer
359 views

MongoDB: Aggregation workaround by helper collection

Since I regularly run against mongodb's document size limit and also aggregation framework's group limitations >16M, depending on the amount of data I need to process, I look for a simple workaround. ...
2
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2answers
444 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 ...
2
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3answers
981 views

mongodb service not running after changing path

I have changed the dbpath of mongodb.conf. And after that trying to start mongodb service,when I run sudo service mongodb start I get back mongodb start/running, process 7320 After that I run: ...
2
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1answer
23 views

Secondary and Arbiter stuck in Startup

I'm using MongoDB version 3.0.0. I'm trying to setup mongodb replication on our machine. Replication was initially setup but due to some changes on the VM the entire thing crashed. When I tried to set ...
2
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0answers
29 views

Mongodb incremental backups

I was given the task to setup incremental backups for mongodb replicaset, as start point of course I googled about it and could not find anything on mongodb docs, I did find however this question ...
2
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0answers
42 views

Why is our Non-Mapped Virtual memory usage high when running MongoDB (MMAP) on CENTOS

Our non-virtual virtual memory usage on our Linux MongoDb instances seems high, currently sitting just over 2GB. The instances are running a minimal installation of CENTOS (no GUI) and they acting as ...