Is there a way to disable the Reactive Mongo plugin on the command line in Play 2.3.x? Something like play.evolutions.enabled=false.
My use case is that I have certain servers that talk to Mongo only & some that talk to another DB only. I want the Mongo servers to be the only ones that connect to Mongo. I don't want to split the code base since it's logically one product.
I'm using
"org.reactivemongo" %% "play2-reactivemongo" % "0.11.1.play23"
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I have an application using a PostgreSQL database with multiple backend-API's. Because we some times run out of connections, I would like to be able to identify which backend API has active connections in view pg_stat_activity. Is it possible to identify the connection from node pg-postgres?
What you see (in pg_stat_activity) is what you get. If none of those fields are helpful, then I guess the answer is no.
Aren't all the APIs pooled together through the same shared connections?
Application_name could help if you can convince node.js to set them per API. query text could help if you recognize what query text is from which API.
We have architecture problem on our project. This project requires sharding, as soon as we need almost unlimited scalability for the part of services.
Сurrently we use Node.js + MongoDb (Mongoose) and MySQL (TypeORM). Data is separated by databases through the simple 'DB Locator'. So node process needs connections to a lot of DBs (up to 1000).
Requests example:
HTTP request from client with Shop ID;
Get DB IP address/credentials in 'DB Locator' service by Shop ID;
Create connection to specific database with shop data;
Perform db queries.
We tried to implement it in two ways:
Create connection for each request, close it on response.
Problems:
we can't use connection after response (it's the main problem, because sometimes we need some asynchronous actions);
it works slower;
Keep all connections opened.
Problems:
reach simultaneous connections limit or some another limits;
memory leaks.
Which way is better? How to avoid described problems? Maybe there is a better solution?
Solution #1 perfectly worked for us on php as it runs single process on request and easily drops connections on process end. As we know, Express is pure JS code running in v8 and is not process based.
It would be great to close non-used connections automatically but can't find options to do that.
The short answer: stop using of MongoDB with Mongoose 😏
Longer answer:
MongoDB is document-oriented DBMS. The main usage case is when you have some not pretty structured data that you have to store, but you don't need to use too much. There is lazy indexing, dynamic typing and many more things that not allow you to use it as RDBMS, but it is great as a storage of logs or any serialized data.
The worth part here is Mongoose. This is the library that makes you feel like your trashbox is wonderful world with relations, virtual fields and many things that should not to be in DODBMS. Also, there is a lot of legacy code from previous versions that also make some troubles with connections management.
You already use TypeORM that may works instead Mongoose. With some restrictions, for sure.
It works exactly same way as MySQL connection management.
Here is some more data: https://github.com/typeorm/typeorm/blob/master/docs/mongodb.md#defining-entities-and-columns
In this case you may use you TypeORM Repository as transparent client that will init connections and close it or keep it alive on demand.
we have a database connected to meteor and loopback services each one edits in the same collection in database.
I found that meteor have to create the model in a way and this link in loopback https://loopback.io/doc/en/lb2/MongoDB-connector.html
includes only connecting to database and create model not to connect already with a collection in database so anyone have an idea how to design and connect the two services with same collection to edit ? or they detect automatically the collections once I connect the datasource?
Yes, this should already work. Meteor uses OPLog tailing to detect changes to the database and it doesn't have any opinion on how the documents in the collection should look like. It will create _ids that are strings rather than ObjectIds, but it can work with either. So as long as the other services doesn't mind the string _ids you should be fine.
I have two Node.js applications each running Mongoose on a different machine. There is a single MongoDB database running on the first, and the second connects to it and adds documents periodically. I'm trying to add a hook to the creation of these documents so the server running the database is aware that other server has added data. I tried using the Schema.post() method, but it doesn't seem to work since there are two separate instances of Mongoose. Is this true or am I just implementing it incorrectly? I can get the hook to fire if the document is created on the same server, but not the other.
So my thought is to add the hook to MongoDB directly, instead of Mongoose, but I'm not sure how to go about doing that. Am I on the right track?
That is true, Schema.post() only work in the same process. You either need to use a library that tails MongoDB's oplog (like mongo-oplog), implement it yourself using a message queue (or pub/sub) that all instances are connected to (like Redis, RabbitMQ, etc) or use a database that supports this natively. PostgreSQL supports this with its NOTIFY feature for example.
I have a node.js app that polls every x seconds a mongodb database to show data variations.
I think there must be a better way to do it, using all the capabilities of node.js environment ... which is the most efficient way to trigger mongodb data variations and showing them using node?
You can use a tailable cursor
http://docs.mongodb.org/manual/tutorial/create-tailable-cursor/