I have a problem with MongoDB when I try to create a collection. That is, I create it and then i check it with the commands:
db.mycollection.find()
or
db.mycollection.count()
And the data comes out, however, after a certain time (minutes), the data of the collections are eliminated by themselves, that is to say they are not persisted, what is happening?
Thanks.
Related
Is there a way to switch off the ability of mongo to sporadically create dbs and collections as soon as it sees one in a query. I run queries on the mongo console all the time and mistype a db or collection name, causing mongo to just create one. There should be a switch to have mongo only explicitly create dbs and collections. I can't find one on the docs.
To be clear, MongoDB does not auto create collections or databases on queries. For collections, they are auto created when you actually save data to them. You can test this yourself, run a query on a previously unknown collection in a database like this:
use unknowndb
db.unknowncollection.find()
show collections
No collection named "unknowncollection" shows up until you insert or save into it.
Databases are a bit more complex. A simple "use unknowndb" will not auto create the database. However, if after you do that you run something like "show collections" it will create the empty database.
I agree, an option to control this behavior would be great. Happy to vote for it if you open a Jira ticket at mongoDB.
No, implicit creation of collections and DBs is a feature of the console and may not be disabled. You might take a look at the security/authorization/role features of 2.6 and see if anything might help (although there's not something that exactly matches your request as far as I know).
I'd suggest looking through the MongoDB issues/bug/requests database system here to and optionally add the feature request if it doesn't already exist.
For people who are using Mongoose, a new database will get created automatically if your Mongoose Schema contains any form of index. This is because Mongo needs to create a database before it can insert said index.
Our collections in MongoDB were automatically deleted/drop and we are not sure why and how. Our MongoDB is working fine for almost 10 months now, so we are really not sure what happened here.
Is there a collection expiration for MongoDB where it automatically delete the collections and its data? Also, would it be possible to retrieve the data?
Thank you in advance!
Collections do not 'drop' themselves.
Someone has run db.collection.drop() somewhere, intentionally, or accidentally.
You can set a TTL on the data inside a collection - see here however I don't think that's what has happened here.
The only way of retrieving the data would be from a backup.
Restoring a backup to a secondary database and taking a copy of the collection in question, then importing that back into your main database may be the best approach here.
... You do have backups, right?
For the last week and a half for some reason my Mongodb collections all get dumped. I can't find a reason why this is happening there doesn't seem to be a real pattern to when/why the collections get dumped. Does anyone have any insight? I'm running Mongodb version 2.6.12.
you can read this artical https://snyk.io/blog/mongodb-hack-and-secure-defaults/
also you can have a look on MongoDB database deleted automatically it should solve your problem.
I am setting up a new ElasticSearch instance using the mongo-connector python tool. The tool is working, but only imported around ~100k entries from the mongodb oplog.
However, my collections contain millions of records... Is there a way to pass all the records from each collection through the oplog without modifying the records in any way?
Following the advice of Sammaye, I solved this problem by iterating over the collection, converting to json, and posting it to the index API via curl. Thanks for the suggestion!
I have a question about indexes in MongoDB.
I am using MongoDB version 1.6.5. I am modifying all my collection indexes.
When I used the show collections command in my MongoDB shell, it showed one of my collections as
system.indexes
stocks
options
Do I need to drop the collection system.indexes to make the new indexes on the collections apply?
Thew system.profile collection is not there however, no you do not. The profile collection is the output of the profiler, nothing more. Indexes will still apply.
Edit
Since your question says two things, no you do not need to drop system.indexes either, MongoDB will handle updating the records in there for you. Dropping it might actually damage your database.