Questions tagged [mongodb]

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

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230 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
494 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
213 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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1answer
2k 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
903 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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3answers
9k views

Write Locks in Mongo DB

I read somewhere that MongoDB 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
1k 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 (...
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1answer
357 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 ...
6
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1answer
5k 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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0answers
365 views

Import only selected column from tsv into mongodb

I have a very large tsv file. I need to upload some data from the file into MongoDB (just two columns, title and body). I don't want to import the full file, as I only really need the two columns. I ...
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2answers
468 views

Does mongodb support non readable files?

I have uploaded PDF/PST file in mongodb by mongofiles, but when retrieving it in R(BSON) and converting it to "Character" type, I couldn't find the PDF/PST file. Is it possible to upload PDF file or ...
9
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1answer
14k 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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3answers
6k 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 ...
3
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1answer
373 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
5k 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
4k 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/ ...
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1answer
89 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
832 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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0answers
164 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 ...
4
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1answer
1k 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 ...
0
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1answer
61 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
1k 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, ...
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2answers
6k views

Mongo DB Can't Start

We have had a mongodb running fine for a few weeks and all of sudden it has gone down. We are unable to start it back up as it is complaining that the dbpath (/data/db/) does not exist. I've tried ...
4
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1answer
5k views

mongostat causing CPU 100%

On a 64Bit Debian 6 OS with 4 CPU cores and 8GB RAM, I can reproduce an issue with mongostat. Whenever I create an index, reIndex or even index in background, according to top, the CPU load is 40-60% ...
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0answers
288 views

MongoDB secondary heartbeat hangs

We have got the same issue in two replica sets in AWS cloud. According to rs.status() on primary secondary jumping between SECONDARY and unhealthy states. With period of 10-20 seconds. In logs I see ...
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1answer
20k views

What happens if there are too many inserts in MongoDB? How to ensure all data is stored?

I use MongoDB to store periodically measured values. Every ~100 ms a bunch of values is inserted as document. It works fine, but I'm worried about performance issues. (I use safe inserts, it seems as ...
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0answers
272 views

Locking and Faulting on import

My collection with a _id and a single field index is run on a single node/on localhost, has 48GB RAM and 16 core CPU available. The hdd is in RAID1, without SSD cache. Mongo version 2.4. I run a ...
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1answer
743 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 ...
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2answers
570 views

Scalability: Desiging a message table

This question might be deadly simple but I wanted to make sure I am going through the correct path and not making any simple and irrevertible mistakes. My project will be based on messaging and it ...
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1answer
667 views

mongos and monod have the same default port?

Is it true that by default mongos and mongod use the same port - 27017? I had to pick a different port for one of these two, for example --port 37017 for mongos.
4
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1answer
991 views

Should I deploy Mongodb sharding for 50 collections?

I have a 10 node clusters that runs about 50 concurrent jobs. Each job needs to read/write a separate collection. So I have about 50 collections roughly. Each collection has about 20 M records. Most ...
5
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3answers
6k 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 ...
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2answers
836 views

MongoDB service not starting on RedHat - missing 'service_uri'

I'm on a Red Hat Enterprise Linux Client release 5.4 (Tikanga) machine I created my /etc/yum.repos.d/10gen.repo like this: [10gen] name=10gen Repository baseurl=http://downloads-distro.mongodb.org/...
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1answer
1k views

monitoring mongodb and mysql replications using nagios

I have set replication for mongoDB and mySQL. Now I have to manage them using nagios. I have to write some php-script that will read server status. I am good with nagios setup. Now I want to know ...
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1answer
4k views

How to find mongo document by ObjectID age

I have a collection of documents I'd like to pull a subset created after a certain point in time. I understand the timestamp of creation is encoded in each documents ObjectID (assuming they are auto ...
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1answer
4k 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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2answers
3k views

MongoDB fast upsert

For non-incremental, but overlapping, imports, I worry about upserts to be very slow and locking the resources for hours. From different sources, I receive 1 json dump per day per source for up to 3 ...
2
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0answers
518 views

Store large hierarchy in NoSQL each day and compare

I'm in the process of creating a utility that stores a fairly large hierarchy into a NoSQL document. The data of this is similar to an Active Directory / LDAP structure which contains sub groupings, ...
2
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2answers
1k views

Is it safe to remove an entry in a “config.mongos” MongoDB collection?

There are old entries in my "config.mongos"; they reference hosts which previously had "mongos" running on them but no longer do. Can I safely remove those entries? e.g.,: # Old entries { "_id" : "...
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1answer
2k views

Storing dynamic data in NoSQL

I have scenario where I need to store unstructured data but the rest of my data is structured and relational. An example of the type of unstructured data is as explained below: User Type 1: How do ...
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1answer
202 views

How would I change this relational model to fit a nosql database?

Because of things beyond my control, I have to switch from a relational database to MongoDB for the advertising platform I'm helping to build. I've got a relational schema sketched out, but I'm unsure ...
2
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1answer
1k views

Would Mongo's ObjectID work well in InnoDB's clustered index?

Mongo's ObjectID is defined like this: ObjectId is a 12-byte BSON type, constructed using: a 4-byte value representing the seconds since the Unix epoch, a 3-byte machine identifier, ...
3
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1answer
327 views

Add new shard - always best? [closed]

In our setup, we currently have 3 shard set sharded cluster, each shard being a replica set of 3. Our writes are about to go up significantly to implement a new feature, and we know the extra data ...
0
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1answer
333 views

Is it possible to upgrade mongodb cluster without upgrading arbiters?

Is it possible to have running real nodes with version 2.4 and arbiter nodes with 2.0 or 1.8 in the replica set? Upgrade guides for version 2.2 and 2.4, did not tell anything about upgrading arbiters....
6
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3answers
7k views

Primary replica set server goes secondary after secondary fails

I have a 2 servers replica set that, after the secondary fails the primary goes into secondary mode while the secondary is in STARTUP2 (recovering). The problem with this is that I can't use the ...
4
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1answer
2k 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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1answer
805 views

Does Mongo have disappearing/phantom writes

I have heard that Mongo has something like phantom writes. For example, if I have a web request with the following db commands in a single unit of work: a) update comments in article b) update ...
6
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1answer
764 views

Are shards distributed randomly across machines in MongoDB or are they in order?

Are shards distributed randomly across machines in MongoDB or are they in order? For example, if I had a MongoDB cluster that was sharded across two machines and my shard key was a person's name, ...
5
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2answers
3k views

Sharded key-value store using MongoDB

Would like to set up a key-value store that is sharded across multiple machines. We are currently using MongoDB, is there a reason why we shouldn't use MongoDB for this purpose? We also use Redis, ...
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1answer
2k views

Is it possible to upgrade MongoDB from 2.0 to 2.4 directly

We have a replica set with 2 members and one arbiter in production. 10gen documentation states that 2.0 to 2.2 is a binary-compatible “drop-in" upgrade and so it's 2.2 to 2.4. Is it safe to upgrade ...