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 start sharding in mongodb

I am trying to learn sharding in MongoDb and here is my plan: I'm trying to shard the database S001 into 2 different machines. 192.xx.xx.60>mongod -configsvr --dbpath S001 ..Now running in ...
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2answers
35 views

Can sharding work with replication?

Basically we need to have a replication, a minimal setup. Primary - Slave 1 - Slave 2 Is it possible in the future we Shared it? What would be the setup? Is it going to have shared on Slaves like ...
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1answer
159 views

Shard keys must all be ascending?

I have a collection that I've been trying to shard, but I can't get it to shard with the index that I gave it. The collection in question uses a hashed index, which I created using: ...
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1answer
60 views

MySQL geospatial query optimisation suggestions

I am new to DB Administration. Trying to sort out this query which is the heart of our application. I am searching google on similar questions, but would like an experts opinion on my particular ...
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1answer
172 views

exception: hosts cannot switch between localhost and hostname

I created a replication set. I added localhost in the set in the beginning, but when I try to edit the member with the actual hostname. I get error "exception: hosts cannot switch between localhost ...
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1answer
90 views

Set replica set member host names on Secondary

I have a replica set rset1 that consists of a primary, secondary, and a backup server. I recently just changed their DNS names in Route53--the only name that didn't change was the Primary's, ...
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1answer
127 views

Would you use MongoDB in high-transaction environment? [closed]

using other words: does the one-write-lock-per-database policy (it's not a "bug" but a "feature" by design) affect contention making its usage in certain kind of workloads less then optimal? if not ...
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1answer
83 views

Mongodb restrict access on collections level

I'm building a backend system using MongoDB. Now I want to restrict access on certain numbers of database collections to this system. For example I have users, admin_users, pageviews and I want this ...
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1answer
58 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
333 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. ...
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0answers
83 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. ...
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1answer
151 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
154 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 ...
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1answer
48 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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2answers
251 views

How secure is mongodb with elastic beanstalk and EC2

I have a questions. I run MongoDB on one of instances of EC2 and application on Elastic BeansTalk. I restricted access to DB: only application can access it. DB instance has Elastic IP because it is ...
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3answers
669 views

Difference between Sharding And Replication on MongoDB

I am just confuse about the Sharding and Replication that how they works..According to Definition Replication: A replica set in MongoDB is a group of mongod processes that maintain the same data ...
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2answers
105 views

Running a simple logging program, how to diagnose spikes mongod's CPU activity?

I'm running mongodb 1.4.7 - I've a node server set up which logs incoming requests in a logs collection: {'u':'user123', 'l':'log data'} In addition, once the request happens, the server will check ...
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1answer
34 views

Replicating MongoDB server on windows

I have a main server(windows-27017) and on that i replicated my data on different port (37017) but same server. Now i am trying to add my notebook as a replicate server on mongodb and installed ...
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1answer
113 views

MongoDB Storage Architecture (MySQL innodb_file_per_table equivalent to MongoDB)

I am new to MongoDB.I looked inside dbpath I found users.0 - 16.8MB users.1 - 33.6MB users.ns - 16.8MB Further when I dig deeper I found, The .0, .1 files are datafiles. Each datafile is ...
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2answers
633 views

How to Determine Chunk Distribution (data and number of docs) in a Sharded MongoDB Cluster?

Having done all the right things - picked an appropriate shard key, scaled horizontally, distributed my data across several shards, I find I now have no real way to determine how well balanced the ...
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1answer
166 views

MongoDB shell version error (Server has startup warnings)

I installed MongoDB under Ubuntu server and when inter to MongoDB shell i got this error and warnings. MongoDB shell version: 2.4.7 connecting to: test Server has startup warnings: Sun Oct 27 ...
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1answer
109 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 ...
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1answer
378 views

“ERROR: could not read from config file” MongoDB

I'm trying to configure MongoDB in OS X Mountain Lion. I've installed with Homebrew; I have followed lots of tutorials, but I have got an issue which I haven't been able to solved. The issue is about ...
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1answer
210 views

Launchctl in MongoDB

I'm trying to configure MongoDB in OS X Mountain Lion. I've installed with Homebrew; I have followed lots of tutorials, but I have got an issue which I haven't been able to solved. The issue is ...
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353 views

Installing mongodb as service

I'm trying to install mongodb as service on a machine running Windows Server 2008R2. I'm getting this message in the command prompt: The service is not responding to the control function. More ...
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228 views

Diffrence between relational and unrelational database [closed]

What is the difference between relational(MySql) and unrelational database(MongoDb)
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102 views

Multiple system.replset collections in local

I have a replicaset that's showing multiple system.replset collection in the local db. replset1:PRIMARY> show collections; me oplog.rs replset.minvalid slaves system.indexes system.profile ...
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1answer
108 views

MongoDB cloneCollection between CentOS servers times out at 2 hours

I'm trying to clone a MongoDB collection from CentOS server A to CentOS server B. Both are running 2.4.6. The copy works great until exaxctly 2 hours, at which point I get a 9001 socket exception: ...
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2answers
96 views

MongoDB scaling when working with files

I have read through the MongoDB manual about sharding and replicasets. However, I would like to know if the following can be achieved with sufficient performance (read/write): Saving 10,000,000 ...
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1answer
63 views

What does maintenanceMode -7 mean on a mongo primary?

I've recently promoted a new member to primary of a mongo replicaset. Things seem to be running smoothly for several days and am not seeing any application symptoms of any problems. However peeking ...
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0answers
110 views

MongoDB advantages [closed]

I am actually can not understand the real advatage or killer feature of MongoDB storage. As I understand currently MongoDB implements exclusive per-database write lock that is even worse from the ...
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1answer
230 views

Need a solution to store cheaply a big MongoDB collection

We have the typical problem of Twitter's timeline tweets, or Facebook profile's news: we need to show the users only the new information (storing them in a fast db), and put all the old ones somewhere ...
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1answer
55 views

Based on what criteria voting take place in MongoDB?

Suppose a replication set R1 contains one primary, 2 secondary and one arbiter node. Voting will happen if the primery node goes down. Based on what criteria secondary members will vote to select the ...
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2answers
1k views

Write Locks in Mongo DB

I read somewhere that mongo db holds db level write lock, does this mean that when someone updates any collection others are not allowed to read other collection or how it works. Also when someone ...
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1answer
383 views

I found the normal ULimit setting for mongo db is as follows:

I found the normal ULimit setting for mongo db is as follows: -f (file size): unlimited -t (cpu time): unlimited -v (virtual memory): unlimited [1] -n (open files): 64000 -m ...
2
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1answer
77 views

Accessing unsharded database in a MongoDB shard cluster without going through mongos?

As far as I can understand, not all databases in a MongoDB shard cluster have to be sharded; I can keep some databases unsharded, on only one of the shards. So suppose I have a shard cluster, with ...
2
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1answer
793 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 ...
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105 views

Import only selected column from tsv into mongodb

Edit I am uploading very big tsv file thats why i dont want to import unnecessary column in mongodb, I know how to upload file into mongodb(just as attachment) as:- mongoimport --db xyztsv--c ...
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2answers
124 views

Does mongodb support non readable file?

I have uploaded PDF/PST file in mongodb by mongofiles but by retrieving them in R(BSON) and converting it to "Character" type i didnt find the PDF/PST file,so is it possible to upload PDF file or PST ...
4
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1answer
2k views

mongodb config servers not in sync

I have setup with 2 shards, with 2 replica servers and 3 config servers, and 2 mongos. I have following problems: 1) mongo config servers out of sync: Aug 14 09:46:48 server mongos.27017[10143]: Sun ...
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2answers
220 views

mongo replication not happening

I setup master/slave replication of mongodb on EC2. But I see not replication happening. When I do "show dbs" on master, it shows all dbs expected. But when I do the same on replica, it does not show ...
2
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1answer
134 views

Memory management scenario with MongoDB

I'm implementing a medium scale marketing e-commerce affiliation site, which has following estimates, Total Size of Data: 5 - 10 GB Indexes on Data: 1 GB approx (which I wanted to be in memory) Disk ...
2
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1answer
1k views

Creating mongo 3 node replica set on ec2 problems

I'm trying to create a 3 node cluster of mongo replicas on ec2 instances, with internal ips 10.168.xxx.xxx, 10.166.xxx.xxx and 10.188.xxx.xxx, my config file is: dbpath = /home/ubuntu/mongo-data/ ...
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1answer
426 views

mongodb user for ubuntu EC2 instance

I am trying to install mongodb on Ubuntu EC2 instance. However, I am confused about what user the DB would run as: If I follow: http://docs.mongodb.org/manual/tutorial/install-mongodb-on-ubuntu/ ...
2
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1answer
55 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 ...
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1answer
250 views

Mongo repair database “ERROR: error: exception cloning object in local.system.replset ”

I'm trying to repair a mongo database and am running into the following error early on: Wed Jul 24 16:55:21 [initandlisten] ERROR: error: exception cloning object in local.system.replset E11000 ...
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64 views

MongoDB RAM requirements doubt

I have a data file with 100 million documents. The number of documents is expected to always remain between 100 million and 200 million for atleast a year. I have 15 GB Ram. Currently the update ...
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183 views

MongoDB performance limits of mongo

There are 100 data files, each with 60 fields and over 4 million records. There is a perl program that inserts the records or updates them based on an userdefined _id field. There is also a History ...
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1answer
37 views

Check and remove iteratively without an index

Without sync priority or performance requirements on the task, I need to check all documents once per day and removing some of them. The find filter is not static but can be defined within a db ...
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1answer
187 views

Preventing mongodb crashes

I am using mongodb with the web server. Recently, I observed that mongodb server crashed after "no space left" for journalling. So, after some online help I could repair and restart the DB. But, ...