After getting some performance issues for an application using a MySQL database, I'm thinking of using NoSQL solutions.

My architecture is as follows:

One application receives messages from the network at a high throughput (i.e. 50000 messages/sec). Each message is stored in the DB, so it's important for the write rate to be as fast as the arrival rate.

Then, I also have some PHP pages that accesses the DB to get the data stored by the other application. It's important for me that the retrieved data is as relevant as possible (i.e. not old data, let's say not more than 5 seconds old).

Also, the data is not critical, so I don't need any security mechanism to avoid losing the data.

I see there are a lot of NoSQL solutions, but I don't know if they are all relevant. Could you please provide me some directions.

Thanks