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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How to determine database read/write ratio on MongoDB MMS?

By looking at MongoDB MMS charts, is there a way to calculate a database read/write ratio, or roughly determine whether a database is read-heavy or write-heavy? Assume I do not have contact with ...
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6 views

Neo4j vs MongoDB (pros and cons)

I am working on a design of a system in which I need to maintain relationship between various kinds of real world entities and also have to handle documents(can have one or more attachments with 1 ...
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9 views

Mongodb x509 certificate for client and cluster member

I am newbie to mongodb, i understood the concepts and architecture in mongodb document. I would like to setup (1) mongodb server and cluster members (2) x509 SSL security for the server, client ...
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106 views

Database Design for NoSQL Fantasy Baseball League

I am trying to create a proper schema to place scraped data into, using a MongoDB database. Currently it looks like Team { id : id, name : String, teamLink : String, username : ...
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14 views

Mongo stuck on save

We have a single node of Mongo holding data in a single collection. We run it on windows 2008 64-bit machine with 128 GB RAM. The size of the collection is ~2TB holding ~200M items. Lately, when we ...
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9 views

Scaling mongoDB & Node.js

Having an app running on Google App Engine, where everything is done for you - I am thinking about moving to mongoDB & Node.js in a Docker system. Would you have one mongoDB instance - and ...
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1answer
156 views

Data Analysis with MongoDB or MySQL

I have a need for processing some data in order to come up with some statistic. This is the scenario: Each user can answer several questions from the question list. They pick their answers from a ...
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1answer
10 views

Mongo import error: exception:read error, or input line too long (max length: 16777216)

I have a shareded collection which I'm trying to migrate from an existing production Cluster running v 2.4 to a new one running 2.6. As both clusters are shareded, I'm using mongoexport from the old ...
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1answer
25 views

Checking records consistency after mongorestore --noobjcheck

I had an HDD malfunction on a Mongo node. After running fsck and mongod --repair I was able to dump the needed collection with mongodump and move it to another server. However, some records appear ...
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284 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 ...
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87 views

Split Vector is taking too much time in mongo shard

I am using mongo shard distribution system. This system performs slow as the data size increases. I checked with profiler and saw split vector is taking to much time while running. It happened after ...
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1answer
383 views

MongoDB problems recovering a member of the replica set

I have a sharded database with 2 replica sets (RS1 and RS2) each one of the RSs with 2 servers. I had a problem yesterday with one member of the RS2, the mongod instance crashed throwing an error. ...
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379 views

verify that mongos server is connected to config servers

I've been writing a backup script for sharded replica-sets and it's almost done, except that I can't seem to get it to successfully start the balancer back up after everything's all said and done. ...
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49 views

Delayed replication false alerts and migration delays

I am running mongo 2.6.1 on a 3-shard cluster. Configuration is: 3 data nodes and 2 arbiters. The one data node is hidden and delayed for 3 hours (slavedelay). I have hidden the node in order to ...
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1answer
685 views

mongodb replication node stuck at “STARTUP2” with optimeDate as 1970

i have just setup replica sets with three nodes . the third node is stuck at stateStr STARTUP2 with "optimeDate" : ISODate("1970-01-01T00:00:00Z"). However its showing no error message. Is this ...
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12 views

Mongo Sort By Added Fields

I'm using MiniMongo which means I won't be able to use aggregations. I'm wondering if there's a way to do this without. I'm basically trying to sort rows by two values, foo and bar. Both are ints, ...
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1answer
158 views

“Host has low open file limits” error in MMS

I am running Standalone MongoDB (v 2.6.0 64-bit) host on Centos (v 6.5). Centos is guest OS on Windows 7 host running under VirtualBox (4.3.10). MongoDB process runs under root account. And it is ...
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1answer
1k views

MongoVUE connect to mongodb with authencation failed!

I had a mongodb ,and a database named genbank ,genbank has a user whose role is "read" and "readAnyDatabase",it is very strange that I cannot connect genbank through this role by MongoVUE ,but I can ...
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1answer
47 views

MongoDB index strategy

I'm developing a system to back-up computers and store the files / data with retention for a while. The actual files are stored in an object store, while I'm planning to keep the metadata of the files ...
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1answer
19 views

MongoDB Server has authorization schema version 3, but found a schema version 1 user

Trying to restore a production MongoDB onto a dev MongoDB and getting this error assertion: 17408 Server has authorization schema version 3, but found a schema version 1 user: { _id: ...
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122 views

MongoDB communication issues on Azure

I have a Python uWSGI app running behind Nginx using pymongo to communicate with a 4 machine replica set running Mongodb 2.6.3. The replica set is configured using domain names for each machine ...
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1answer
46 views

Is there way to have logical connection in MongoDB?

For example in oracle we can define tns.ora so client can connect with logical name. Although mongos can run on client servers, but when there are many different partner applications we we will need ...
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1answer
188 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 ...
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64 views

Selecting, filtering and aggregating in MongoDB

if we have two dataset 1-First dataset contains population data of cities in the United States of America. Each record in the dataset has the following format: { "city": "ACMAR", "loc": [ ...
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45 views

1 million strings and exact match search

I need to chose the best solution (software and algorithm) to solve my problem. I need to store up to million strings and data associated with them. Strings are search queries and data is cached ...
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49 views

Understanding document size in MongoDB

My collection.stats(): { "ns" : "csdbprotobuf.archive", "count" : 429787895, "size" : 48374032272, "avgObjSize" : 112, "storageSize" : 56527326864, "numExtents" : 47, ...
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137 views

MongoDB text index and text search

I have a mongodb collection db.articles,it has 2 keys ,"title" and "abstract".I want to do text search on these two keys.For example, the search text is "physics",and I want all the documents whose ...
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1answer
51 views

CRC checkup in MongoDB

I am new to MongoDB and currently working on a project. I read tutorials but I'm unable to find any information about Cyclic Redundancy Check (CRC) in MongoDB. Is there any way to check that the data ...
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1answer
18 views

Updating Document in MongoDB without Alphabetically order

I am making one project on MongoDB and inserted some documents and now i am updating the documents by this code.. bson_init( query ); bson_append_string(query, "First", "A"); ...
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2answers
3k views

Mongo replicated shard member not able to recover, stuck in STARTUP2 mode

I have following setup for a sharded replica set in Amazon VPC: mongo1: 8G RAM Duo core (Primary) mongo2: 8G RAM Duo core (Secondary) mongo3: 4G RAM (Arbiter) Mongo1 is the primary ...
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26 views

MongoDB thinks it's running a replica?

I'm running MongoDB (version 2.4) behind a Django application served by Apache. In the past few days, I'm seeing the following error come up many times an hour in the Apache logs, on all sorts of ...
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users and roles in mongodb

Following users are created in mongodb. First user created with name "user" having read write role for "project" database use project db.createUser( { user: "user", pwd: "user123", ...
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59 views

Mongodb replica sets: why does my master server occupy more disk space than my slave?

I have two servers on my replica set. Let's call it the master and the slave, for the purpose of this discussion. The master was the original one, and the slave was replicated from that master. At ...
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19 views

Data Migration or Sharded Cluster to new Cluster

We have Sharded Mongo Cluster. However some documents are sharded and others are unsharded. We are planning to migrate these databases to new cluster. Please update if there is any process or steps ...
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1answer
26 views

Disable MongoDB journaling?

Are there any benefits in disabling mongodb journaling besides performance gain? I know journaling provides write durability and crash resiliency. But I can tune syncdelay parameter to make data files ...
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12 views

Exception in 'hibernate.ogm.datastore.database'

I am trying mongodb with hibernate-ogm i am completely new for hibernate-ogm i have stucked with following exception. I am using hibernate-ogm 4.1 6beta version and mongodb-ogm-hibernate.4.1 jar. ...
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1answer
20 views

MongoDB syncingTo change

I have a 3 members replica set version 2.6.1 with following configuration "_id" : 0, "host" : "10.125.16.22:30000", "priority" : 2 ...
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1answer
21 views

What is the easiest way to start a mongodb copy server?

Our mongodb server is running on AWS EC2 - it is using up a lot of the cpus of this server - which is also our Apache server - How Can I easily migrate the mongodb to another EC2 dedicated server?
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1answer
25 views

How to confirm that chunk transfer is completed on a DB

I have one case where i create db for Daily data. I have some collections in this db which are sharded. My requirement is as follows: Create every day DB If There is a DB which is more than 7 days old ...
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1answer
200 views

Best embed/reference/field strategy for many inserts (mongo)

I'm building a gaming backend with Mongo, and have some issues on how to best design the schema to maximize performance and database size. My models: User Match -ReferenceMany (User) ...
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1answer
60 views

mongodb on-premise: will it work?

We are planning to package MongoDB-PostgreSQL hybrid solution in our application that will be deployed on customer site on-premise. It will be packaged as a software virtual appliance. Our reason for ...
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1answer
159 views

What is lock pinger in mongodb

Can somebody explain me what is lock pinger in MongoDB [LockPinger] cluster XXXXXXX:27019 pinged successfully at Wed Feb 5 04:46:01 2014 by distributed lock pinger ...
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9 views

where did my mongo databses go?

I have various Mongo databases and when I do ls -l in my CentOS linux I can see the databaseA.0 and databaseA.ns files for each database and the file size is large enough to tell my data is still ...
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33 views

In shard cluster, if 2 replica set nodes are offline leaving only 1 secondary..where do writes go?

This is probably a simple question that i can't get definitive answer too. If i have 10 shards, each being a 3 node replica set. If i loose 2 servers in a replica set causing the primary to change to ...
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1answer
29 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
15 views

PHP/MongoDB: Unset all fields in a document

I want to use PHP to remove documents from a MongoDB collection, but it's a capped collection (and it's stuck that way until I can get more memory), which means I can't remove documents. I have to do ...
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1answer
21 views

Tracing the origin of noTimeout cursors

I'm currently managing a Mongo DB instance that has several applications using it. It's been accumulating noTimeout cursors, and, while it's easy enough to cull them if they start getting ...
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1answer
15 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 ...
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1answer
12 views

MongoDB Booleans

In MongoDB, I could store a boolean like so: active: True But that doesn't really take advantage of NoSQL, since there's no reason to have the active property at all if it's false. Is there a way ...
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279 views

optimizing MySQL for traffic analytics system

background : I've developed a URL shortener system like Bitly with same features , so the system also tracks clickers info and represent as graphs to the person who has shorten the link as ...