#Django aws postgresql host code#
We can create a custom router that can use the default instance for write operations and choose a random replica in the read ones.Serverless computing revolutionizes cloud infrastructure by having developers provision services and define resource demands with code rather than manually configuring hardware from scratch. The alternative to it is using a Django database router. Moreover, imagine that in the future we create more replicas we'll need to review all the code and manually select which replica to use in each of these operations. However, this solution doesn’t scale because it's the developer’s responsibility to detect when it is a read-only operation and choose the replica. save ( using = 'replica_1' ) Configuring a Router to Choose the Read Replicas When RequiredĪfter the previous step, we have the replicas instance available for the Django application, and we can access it manually when it is required. # The operation will throw an error u = User ( email = ) u. save () # Try to save the instance in the replica instance. # The operation is OK u = User ( email = ) u.
# To save the instance in the default database. For example, if we have configured two replicas, the settings file should look like this: The idea is to set the master instance (read/write server) as the default database and declare all the read replicas as additional databases. This step is easy and can be done following the official documentation for multiple databases. To allow the usage of the read replicas, we need to declare them as additional databases in the Django settings file. To configure and use read replicas in a Django app we need to take care of these points:ĭeclaring the read replicas instances as databases in the Django applicationĬonfiguring a router to choose the read replicas when requiredĭeclaring the Read Replicas Instance as Databases In this post, we will talk about the second configuration, assuming that the read replica is updated in a synchronous way. In that schema, the replication and the synchronization of data can be done synchronously or asynchronously. When we talk about replication in databases, we are talking about having several servers running with the same "data." There are several configurations available to implement database replication, for example:Ī single master instance (that allows read/write) and several read-only instances.
#Django aws postgresql host software#
The idea of replication in software and hardware refers to the technique of using multiple copies of a resource in order to guarantee performance, availability, and fault tolerance. Fortunately, the database has a solution for that problem: replicas. If the number of connections is high, the database doesn’t have enough resources to deal with all of them in real time, bringing up performance issues. If we have a system with a single database that is used by thousands of users, the number of connections that are hitting it will be considerable. However, a well-designed schema is not a guarantee of a good performance, and there are other factors that can affect it, like the number of connections, for example.
A database that wasn’t designed with the expected operations in mind probably will have a poor performance. One of the most common is having the wrong schema design. The database is one of the main sources of slowness that a system can have, and it can be generated by several factors. In this post we will focus on performance issues related to the database and how we can deal with them using read-replicas. They can be generated by several factors, such as hardware, network issues, a non performant program, etc. Performance issues usually appear in large systems and are difficult to diagnose because they are difficult to reproduce (sometimes, the issue only occurs in a specific environment). One of the most common problems related to architectures is performance. The wrong choice of architecture can result in a nonfunctional site that could affect your business. One of the most important tasks in software engineering is to choose an architecture that best suits a specific problem.
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