I have a problem removing records from a capped collection. DB is complaining that command doesn't exists.
There is a collection that is capped. I have verified by issuing isCapped().
I switch to a db that contains the collection.
Then I run
db.runCommand({ emptycapped: 'events'})
as a result I get :
{
"ok" : 0,
"errmsg" : "no such cmd: emptycapped",
"bad cmd" : {
"emptycapped" : "events"
}
}
Environment details :
MongoDB shell version: 2.2.0
Mongod Server version: 2.4.1 on Ubuntu 12.04
Any ideas what could be the possible cause ?
As Enrique Fueyo's commented:
In the docs (http://docs.mongodb.org/manual/reference/command/emptycapped) you can read that "...is not enabled by default. emptycapped must be enabled by using --setParameter enableTestCommands=1 on the mongod command line."
You need to start mongo with a command such this:
$ mongod --config /usr/local/etc/mongod.conf --setParameter enableTestCommands=1
Related
yes I just started to understand MongoDB. Therefore I have installed MongoDB in the folder "Program files" yesterday and tryed to figure out, how to work with it.
Today I simply tryed to start it again. But something went wrong. To understand the beginning better I deinstalled MongoDB, deleted the MongoDB, data, log folders and have installed MongoDB again direct on c:/.
Started the server:
mongod --directoryperdb --dbpath c:\mongodb\data\db --logpath c:\mongodb\log\mongo.log --logappend --auth --rest --install
Started the service:
net start MongoDB
And the Mongo shell:
mongo
Now I try "show dbs" with the following result:
>show dbs
2017-09-14T10:41:49.541+0200 E QUERY [thread1] Error: listDatabases failed:{
"ok" : 0,
"errmsg" : "not authorized on admin to execute command { listDatabases: 1.0 }",
"code" : 13,
"codeName" : "Unauthorized"
} :
_getErrorWithCode#src/mongo/shell/utils.js:25:13
Mongo.prototype.getDBs#src/mongo/shell/mongo.js:62:1
shellHelper.show#src/mongo/shell/utils.js:769:19
shellHelper#src/mongo/shell/utils.js:659:15
#(shellhelp2):1:1
More I haven't done already. What can I do to show the dbs?
Of cource, I have tryed the learnings of the following post to, without success:
show dbs gives "Not Authorized to execute command" error
Looks like you are starting the db with --auth but not connecting with username/password. If you have not created any user then remove --auth and restart db. Then you will be able to connect.
I am new to mongo db.
I just installed mongo DB on my MAC,
After watching this Youtube Video
https://www.youtube.com/watch?v=pWbMrx5rVBE&t=369s
In mongo shell, I entered show dbs and I get wired output.
Kindly help me to understand and solve this
> show dbs
2017-09-11T02:45:34.298+0530 E QUERY [thread1] Error: listDatabases failed:{
"ok" : 0,
"errmsg" : "unable to open cursor at URI statistics:table:collection-2-2362555297355466682. reason: No such file or directory",
"code" : 43,
"codeName" : "CursorNotFound"
} :
_getErrorWithCode#src/mongo/shell/utils.js:25:13
Mongo.prototype.getDBs#src/mongo/shell/mongo.js:62:1
shellHelper.show#src/mongo/shell/utils.js:769:19
shellHelper#src/mongo/shell/utils.js:659:15
#(shellhelp2):1:1
After a couple of research, I found the solution and sharing all I learned so no new learner struggles like me.
My mistake :
I was staring mongodb using :
mongod --config "c:\MongoDB\Mongod.cfg"
and start mongo shell by just running
mongo
Starting Mongo DB and Shell
Then understood, what each command does :
|*| Start Mongo DB with default config :
mongod
|*| Start Mongo DB with config file :
mongod -f "c:\MongoDB\Mongods.cfg"
|Or|
mongod --config "c:\MongoDB\Mongod.cfg"
|O| Start Mongo DB with config flags :
mongod --dbpath "c:\mongodb\data\nameMdb" --logpath "c:\mongodb\log\nameMdbLog.log" --directoryperdb --logappend
So correspondingly we should use mongo also to start shell :
|*| Start Mongo shell with default config :
mongo
|*| Start Mongo shell with localhost config flags :
mongo --host localhost --port 28888
|*| Start Mongo shell with public config flags and user details :
mongo --username <user> --password <pass> --host <Host.IP.Adrs> --port 28888
|*| Creating Config File is explained here with example :
https://github.com/mongodb/mongo/blob/master/rpm/mongod.conf
I had a similar issue when configuring MongoDB for replication.
When I run the command below:
mongo
show dbs
I get the error:
> show dbs
uncaught exception: Error: listDatabases failed:{
"topologyVersion" : {
"processId" : ObjectId("60ddea05beb1d89d4d139546"),
"counter" : NumberLong(0)
},
"ok" : 0,
"errmsg" : "not master and slaveOk=false",
"code" : 13435,
"codeName" : "NotPrimaryNoSecondaryOk"
} :
_getErrorWithCode#src/mongo/shell/utils.js:25:13
Mongo.prototype.getDBs/<#src/mongo/shell/mongo.js:147:19
Mongo.prototype.getDBs#src/mongo/shell/mongo.js:99:12
shellHelper.show#src/mongo/shell/utils.js:937:13
shellHelper#src/mongo/shell/utils.js:819:15
#(shellhelp2):1:1
Here's how I fixed it:
The issue was that I had enabled the replication feature in the /etc/mongod.conf file without initializing the replication, so MongoDB could not tell which replica was the primary replica or secondary replica.
All I had to do was to comment out the replication feature in the /etc/mongod.conf file since I was not yet ready to set up replication:
#replication
# replSetName: my-replica-set-name
After which I restarted the MongoDB server:
sudo systemctl restart mongod
This time the command ran fine.
I experienced this issue today, installing the latest version of MongoDB with Homebrew and then launching the mongo shell and entering the command "show dbs". I tested this multiple times and spent some time researching it. The symptoms match an issue that was reported here: https://jira.mongodb.org/browse/SERVER-20753 where the issue was described as building WiredTiger separately from MongoDB and using an out of date version of WiredTiger.
While this is not the case for what you and I have experienced (note that Homebrew is currently installing 3.4.9 and WiredTiger 2.9.2), I guessed that it could be a similar mismatch between WiredTiger and MongoDB, so I decided to try installing a different version.
I ended up installing the latest "dev" version using this Homebrew command:
brew install mongodb --devel
This installs MongoDB 3.5.13 and WiredTiger 3.0.0 which do not have the issue. Note that 3.4.9 was released the day you reported this issue and 3.5.13 was released the next day, although 3.4.9 is still the current community edition listed here: https://docs.mongodb.com/manual/tutorial/install-mongodb-on-os-x/
In my case, the problem was replSet name.
I was changed my hostname at the Sharing preference and it was different with the previous installed replSet config's host name.
You can see the rs.config() in mongo shell like this.
"members" : [
{
"_id" : 0,
"host" : "MBA.local:27777",
"arbiterOnly" : false,
"buildIndexes" : true,
"hidden" : false,
"priority" : 1,
"tags" : {
},
"slaveDelay" : NumberLong(0),
"votes" : 1
}
],
See the host: section and change it by rs.config({object}) command in mongo shell,
or just add the line below at the /etc/hosts file.
127.0.0.1 MBA.local
I have got this issue while working on replica sets. Server is successfully turning on but after executing rs.initiate() and rs.status I am getting errors.
"info2" : "no configuration explicitly specified -- making one",
"errmsg" : "exception: bad --replSet config string format is: <setname>[host1>,<seedhost2>,...]",
"code" : 13093,
"ok" : 0
I ran into this problem as well. What happened was I configured the replica set in /etc/mongo.conf, went into the mongo client and executed rs.initiate(). What I forgot to do was restart mongo! A simple sudo service mongod restart fixed it.
Consider, I have 4 replicate sets and the config is as follows:
{
"_id": "rs_0",
"version": 5,
"members" : [
{"_id": 1, "host": "127.0.0.1:27001"},
{"_id": 2, "host": "127.0.0.1:27002"},
{"_id": 3, "host": "127.0.0.1:27003"},
{"_id": 4, "host": "127.0.0.1:27004"}
]
}
I am able to connect to all sets using
mongo --port <port>
There are documents for getting information on Convert a Standalone to a Replica Set, but can anyone tell me how to convert back to standalone from replica set?
Remove all secondary hosts from replica set (rs.remove('host:port')), restart the mongo deamon without replSet parameter (editing /etc/mongo.conf) and the secondary hosts starts in standalone mode again.
The Primary host is tricky one, because you can't remove it from the replica set with rs.remove.
Once you have only the primary node in the replica set, you should exit mongo shell and stop mongo. Then you edit the /etc/mongo.conf and remove the replSet parameter and start mongo again.
Once you start mongo you are already in standalone mode, but the mongo shell will prompt a message like:
2015-07-31T12:02:51.112+0100 [initandlisten] ** WARNING: mongod started without --replSet yet 1 documents are present in local.system.replset
to remove the warning you can do 2 procedures:
1) Droping the local db and restarting mongo:
use local
db.dropDatabase();
/etc/init.d/mongod restart
2)Or if you don't want to be so radical, you can do:
use local
db.system.replset.find()
and it will prompt a message like:
{ "_id" : "replicaSetName", "version" : 1, "members" : [ { "_id" : 0, "host" : "hostprimary:mongoport" } ] }
then you will erase it using:
db.system.replset.remove({ "_id" : "replicaSetName", "version" : 1, "members" : [ { "_id" : 0, "host" : "hostprimary:mongoport" } ] })
and it will probably prompt:
WriteResult({ "nRemoved" : 1 })
Now, you can restart the mongo and the warning should be gone, and you will have your mongo in standalone mode without warnings
Just remove a host from replica set (rs.remove('host:port')), relaunch it without replSet parameter and it's standalone again.
On an Ubuntu Machine
Stop your mongo server
open /etc/mongod.conf
Comment the replication and replSetName line
#replication:
#replSetName: rs0
Start your mongo server and go to mongo shell
drop local database
use local
db.dropDatabase()
Restart mongo
The MongoDB Documentation suggests the following to perform maintenance on a replica set member, which brings the the replica set member into standalone mode for further operations. With little modification it can be made standalone:
If node in concern is the only node in a shard, drain the chunks to other shards as per MongoDB documentation here, or else the sharded database will break, i.e.
Make sure balancer is enabled by connecting to mongos and run sh.startBalancer(timeout, interval)
For the shard in concern, go to admin database and db.adminCommand( { removeShard: "mongodb0" } )
Check draining status by repeating above removeShard command, wait for draining to complete
If node in concern is primary, do rs.stepDown(300)
Stop the node by running db.shutdownServer()
Change the yaml config by:
commenting out replication.replSetName (--replSetName in command line)
commenting out sharding.clusterRole for shard or config server (--shardsvc and --configsvr in command line)
commenting out net.port, then change it to a different port (--port in command line)
Start the mongod instance
If change is permanent, go to other mongod instance and run rs.remove("host:port")
After this, the node in concern should be up and running in standalone mode.
Follow below steps :
Go to mongo shell on Secondary servers
Stop the secondary servers by using below command :
use admin
db.shutdownServer()
Go to Linux shell- on secondary servers and type below command :
sudo service mongod stop
Starting the MongoDB replication -
Go to Linux shell - on secondary servers and type below command :
sudo service mongod start
Starting the MongoDB replication -
Go to primary and type below commands to start the replication :
a] rs.initiate()
b] rs.add("Secondar -1:port no")
c] rs.add("Secondary-2:port no")
d] rs.add({ "_id" : 3, "host" : "Hidden_member:port no", "priority" : 0,
"hidden" : true })
e] rs.status()
I am using the MongoDB 2.4.3, and following the wizard:
http://docs.mongodb.org/manual/tutorial/deploy-replica-set/
But when adding the other members into replica-set, get the following error:
root#vm3:~# mongo
MongoDB shell version: 2.4.3
connecting to: test
rs1:PRIMARY> rs.add("vm1")
{
"errmsg" : "exception: set name does not match the set name host vm1:27017 expects",
"code" : 13145,
"ok" : 0
}
rs1:PRIMARY> rs.add("vm4")
{
"errmsg" : "exception: set name does not match the set name host vm4:27017 expects",
"code" : 13145,
"ok" : 0
}
vm1, vm3 and vm4 know each other because I configured their /etc/hosts files correctly.
Any idea? I don't understand what does this error message mean!
After restarting all vms, it works now.
root#vm3:~# mongo
MongoDB shell version: 2.4.3
connecting to: test
rs1:PRIMARY> rs.add("vm4")
{ "ok" : 1 }
rs1:PRIMARY> rs.add("vm1")
{ "ok" : 1 }
In my case, just restart virtual machines, every thing is fine.
If you are re-installing a MongoDB instance, the replSet may be living in your data file on the drive. I had the same problem setting up a new replica set. The problem was from changing the replica set name after bringing up instances with an older replSet name. I deleted the data files, ran my install scripts again and it worked just fine.