34
votes
Accepted
How to specify authentication database and target database separately on mongodb connection uri?
Yes.. Easily!
mongo "mongodb://test:testpwd@localhost/test?authSource=admin"
MongoDB shell version v3.4.6
connecting to: mongodb://test:testpwd@localhost/test?authSource=admin
MongoDB server version: ...
- 5,723
13
votes
Accepted
How to views all documents in a particular collection of database in MongoDB through mongo Shell?
OK, let's start from basics!
After you have connected to mongod with command mongo.
List databases with command show dbs
iot:PRIMARY> show dbs
admin 0.000GB
iot 0.020GB
local ...
- 5,723
10
votes
Accepted
mongorestore Too many open files
ulimit can be set in the same terminal by
ulimit -n 10000;
You can change the value in /etc/security/limit.conf file by
nofiles to 10000 #line
the maximum no of files can be opened in any linux/...
- 141
8
votes
Accepted
Mongodb Secondary Node not recovering
Link in the error message exactly explain what happened.
A replica set member becomes “stale” when its replication process
falls so far behind that the primary overwrites oplog entries the
...
- 13.6k
7
votes
Accepted
Multiple BindIp in MongoDB 3.4.1 on Debian Jessie
Remove []. so solution is: bindIp: 127.0.0.1,192.168.20.1 and remember, no space characters anywhere in that string.
- 5,723
5
votes
How to views all documents in a particular collection of database in MongoDB through mongo Shell?
Ref:
https://docs.mongodb.com/manual/tutorial/query-documents/
Select All Documents in a Collection
To select all documents in the collection, pass an empty document as the query filter parameter ...
- 13.6k
4
votes
Accepted
Service mongod fails after adding security.keyFile in config file
Use full path for keyfile. Don't use ~ -character there. Your mongod is started (probably) with user 'mongod' and that user don't have home directory.
Additionally keyfile must be have chmod 0400 and ...
- 5,723
4
votes
How to specify authentication database and target database separately on mongodb connection uri?
Ref:
https://docs.mongodb.com/manual/reference/connection-string/#connections-connection-options
You will need to use below format and do not need to use admin database.
mongodb://user:password@...
- 13.6k
4
votes
MongoDB Maxing CPU Usage
Strange indeed.
That local.oplog.rs is journaling what is enable (default) at 64 bit systems (32bit default value is false). So, running time for that thread should be same than your mongod uptime.
...
- 5,723
4
votes
mongo crashing due to too many open files
I have gone through your error and find out that in your case the Open file limit is 990000. Which is sufficient to open the mongos and mongod process. As per MongoDB BOL Here The default net....
- 6,477
4
votes
Accepted
Save output of a Mongo Command to a Variable bash script
Mongo -command have multiple parameters that are handy in this case.
'--eval' let you run commands and '--quiet' keep all clutter away
out=$(mongo --quiet --eval="db.currentOp()") ; echo $...
- 5,723
3
votes
Accepted
Is MongoDB IXSCAN operator a scan or a seek?
I guess MongoDB can do index seek and index scan ?
Yes MongoDB can do index seek and index scan, but it can do both during one fetch. That is what happened in your case. If started with a seek to ...
- 13.6k
3
votes
Accepted
Why `distinct` and `count` operations generate `"op": "command"` in system.profile
Originally, all database operation in MongoDB are encoded in the Wire Protocol. However, this would mean that creating a new command would involve:
Creating a new opcode in the wire protocol, and
...
- 548
3
votes
Accepted
How to set up a user who doesn't have `admin` database access but use it as authentication database?
Not need. You just give user needed rights to the wanted non-admin database. User can use admin database as authentication database even user doesn't have read/write access to admin database.
use ...
- 5,723
3
votes
MongoDB secondary node does not become primary when other nodes are stopped
This is by design. If you want to run with only one node, restart that node without replica set switch.
If a majority of the replica set is inaccessible or unavailable to the
current primary, ...
- 13.6k
3
votes
Replica Set not getting created
OK.. It's look like that you have managed to mix things. So, you have working mongodb at "C:\program files\mongodb\data" and now you want to convert that mongodb to three node replica set?!?
First ...
- 5,723
3
votes
Accepted
WiredTiger internal cache
Do we need to keep extra memory for some kind of memory mapped files for MongoDB data files
The mem.mapped and mem.mappedWithJournal metrics in serverStatus output are only applicable to the MMAPv1 ...
- 10.3k
3
votes
What's the difference between DISTINCT_SCAN and IXSCAN in explain output?
They are different stages for different purposes. I believe DISTINCT_SCAN is only present when there is an index in the field. An IXSCAN stage basically means that the query planner scans an index as ...
- 548
2
votes
Bind MongoDB to IPv4, as well as IPv6
As per MongoDB BOL Here
To bind to all IPv4 addresses, enter 0.0.0.0.
To bind to all IPv4 and IPv6 addresses, enter 0.0.0.0,:: or alternatively, use the net.bindIpAll setting.
Note: Before you bind ...
- 6,477
2
votes
Bind MongoDB to IPv4, as well as IPv6
Did you find an answer yet? If not, here is the solution:
IPv6 is disabled by default, you have to enable it for binding on IPv6. The following net-config should work:
net:
ipv6: true
port: ...
2
votes
Accepted
Restoring the database dump of a newer version to an older version of mongodb
Assuming you aren't using any newer features or index/collection options from MongoDB 3.2+ that aren't supported in MongoDB 3.0, you should be able to restore the backup.
Before doing so, I would ...
- 10.3k
2
votes
Accepted
service mongod cant start, permission denied mongod.lock when changing dbpath
If you now command:
sudo chown -R mongodb:mongodb /home/user/mongodb
sudo service mongod restart
It will work!
Problems here was that you gave command sudo mongod --dbpath /home/user/mongodb/data/ ...
- 5,723
2
votes
Accepted
Transferring Mongodb database with rsync while working, is it okay?
No, not directly! If your data is top of LVM, do a snapshot and copy that to another node, start it and connect it to the replica set. This only if you have lot's of data and normal initial sync (as @...
- 5,723
2
votes
Issue with MongoDB Replication Set
I fixed the issue by adding below lines in /etc/mongod.conf
replication:
replSetName: yogi
- 121
2
votes
Accepted
What is the behavior of null/empty value in compound shard key?
In MongoDB 'null' is just another value so two documents that have the same values for field1 (some non-null) and same value for field2 (null) have the same value for the shard key and will always be ...
- 650
2
votes
Accepted
MongoDb linearizable read concern restrictions
Dmitry,
As of MongoDB v3.6, MongoDB only supports the linearizable read concern on single documents, hence the wording of the documentation. However, it doesn't mean you have to run the query using a ...
- 254
2
votes
How to run mongod from the commandline?
Because nothing is written to log file, the first (and only) problem is (probably) ownership of log file. Usermongodb don't have access to that file. sudo chown -R mongodb: /var/log/mongodb should fix ...
- 5,723
2
votes
Accepted
Mongodb Standalone Performs better than Replica Set
I would like to know what could be the real reason for the replica sets to function slower compared to the standalone db.
Replica sets provide high availability and data redundancy, but these ...
- 10.3k
2
votes
MongoDB multiple Cluster data sync
1)MongoDB - Multiple cluster data synchronizing master to master
As MongoDB jira documentation Why was MongoDB not designed to have master-master replication actually, don't think master-master ...
- 6,477
2
votes
MongoDB update multiple sub documents inside array, each according to a condition
Use the arrayFilters property:
db.getCollection("test").updateOne(
{
"wid": 1
},
{
$inc: {
"items.$[aa].sent": 37,
"items.$[bb].sent": 58,
...
- 532
Only top scored, non community-wiki answers of a minimum length are eligible