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Tag Archives: MongoDB

MongoDB Facts: Lightning speed aggregation

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In my previous post, I demonstrated how fast you can insert 50 millions time-event entries with MongoDB. This time we will make use of all that data to fuel our aggregation tests. This is how one time-event entry looks like:             { "_id" : ObjectId("529a2a988cccdb538932d31f"), "created_on" : ISODate("2012-05-02T06:08:47.835Z"), "value" : 0.9270193106494844 } Beside the default ...

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Create a simpe RESTful service with vert.x 2.0, RxJava and mongoDB

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A new article after an hiatus of almost half a year. In this article we’ll have quick look at how you can get started with vert.x and more interestingly how you can use RxJava to make programming asynchronous systems a lot easier. We’ll cover the following subjects: Create an empty vert.x project using maven Import in IntelliJ and create a ...

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MongoDB Facts: 80000+ inserts/second on commodity hardware

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While experimenting with some time series collections I needed a large data set to check that our aggregation queries don’t become a bottleneck in case of increasing data loads. We settled for 50 million documents, since beyond this number we would consider sharding anyway. Each time event looks like this:           { "_id" : ObjectId("5298a5a03b3f4220588fe57c"), "created_on" ...

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Spring Data MongoDB cascade save on DBRef objects

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Spring Data MongoDB by default does not support cascade operations on referenced objects with @DBRef annotations as reference says: The mapping framework does not handle cascading saves. If you change an Account object that is referenced by a Person object, you must save the Account object separately. Calling save on the Person object will not automatically save the Account objects ...

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Auditing Entities in Spring Data MongoDB

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Spring Data MongoDB 1.2.0 silently introduced new feature: support for basic auditing. Because you will not find too much about it in official reference in this post I will show what benefits does it bring, how to configure Spring for auditing and how to annotate your documents to make them auditable Auditing let you declaratively tell Spring to store: date ...

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Optimistic locking retry with MongoDB

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In my previous post I talked about the benefit of employing optimistic locking for MongoDB batch processors. As I wrote before, the optimistic locking exception is a recoverable one, as long as we fetch the latest Entity, we update and save it. Because we are using MongoDB we don’t have to worry about local or XA transactions. In a future ...

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MongoDB optimistic locking

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When moving from JPA to MongoDb you start to realize how many JPA features you’ve previously taken for granted. JPA prevents “lost updates” through both pessimistic and optimistic locking. Optimistic locking doesn’t end up locking anything, and it would have been better named optimistic locking-free or optimistic concurrency control, because that’s what it does anyway. So, what does it mean to ...

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MongoDB and Web applications

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Today’s era is when data grows at very huge scale. Data storage is not a problem, yes but the way it gets structured and stored may increase or decrease the seek time for needed data blocks. Use Cases of ever increasing unstructured data           Facebook: 750 million users are active , 1 in 3 Internet users ...

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MongoDB Pro Tip: Field Projections

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Did you ever learn that select * from table in RDBMS-land is bad? Of course, you did! If you’re only looking for the email address of a user and not the other 15 columns worth of data, then why ask for that data and incur a penalty? The query select email from user where user_id = 1; is far more ...

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