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Corrado PandianiMongoDB has always made it relatively easy to scale horizontally, but with version 8.0, the database takes a significant step forward. If you’re working with large datasets or high-throughput applications, some of the changes in this release will make your life a lot easier — and your architecture cleaner. Let’s take a look at some […]
This blog was originally published in March 2021 and was updated in February 2025. Good intentions can sometimes end up with bad results. Adding indexes boosts performance until it doesn’t. Avoid over-indexing. The difference between your application being fast, responsive, and scaling properly depends on how you use indexes in the database. MongoDB is no […]
MongoDB provides scalability and high availability at ease. If you already have a sharded cluster, you know for sure what the Balancer does. If you are not an experienced MongoDB user, the Balancer is one of the key components of a sharded cluster, and the main goal is to maintain the cluster balanced, moving chunks […]
MongoDB is a schemaless database that is extremely flexible. When you create a collection, you don’t have to specify a structure in advance, providing field names and data types. Just start inserting JSON documents, and MongoDB will store them, no matter which fields and data types you provide. As a consequence, a collection can store […]
In this article, I want to discuss a couple of pretty new features in MySQL 8.0 — and an older one. Maybe these are minor features you are not aware of, and maybe not so relevant, to be honest. But it is worth providing a quick overview, showing how they work, and how they could […]
This blog was originally published in January 2022 and was updated in July 2023. Working with hundreds of different customers, I often face similar problems around running queries. One very common problem when trying to optimize a database environment is index usage. A query that cannot use an index is usually a long-running one, consuming […]
Are you familiar with the UNION statement for your SQL queries? Most likely, you are. It has been supported for a long time. In case you are not familiar with UNION, don’t worry, I’m going to show you how it works with simple examples. Considering “Set Theory”, other than the UNION, starting from the newly […]
I have recently written an article for this blog presenting Window Functions for MongoDB 5.0. I used some public Italian COVID-19 data for a few real examples. Please have a look at it if you like. Then I thought I should provide the same even for a relational database like MySQL. MySQL introduced Window Functions […]
I have already presented in previous posts some of the new features available on MongoDB 5.0: resharding and time series collections. Please have a look if you missed them: MongoDB 5.0 Time Series Collections Resharding in MongoDB 5.0 In this article, I would like to present another new feature: window functions. Window functions are quite […]
In a previous article, I tested a new feature of MongoDB 5.0: resharding. Today, I take a look at another new feature: the Time Series collections. The Time Series collection is an astonishing new feature available in MongoDB 5.0. Based on the first tests I have done, the Time Series support provides comparable performance to […]
MongoDB 5.0 has been released with a bunch of new features. An important one is the capability to completely redefine the shard key of a collection in a sharded cluster. Resharding was a feature frequently requested by the customers. In MongoDB 4.4 only the refining of the shard was available; from now on you can […]
It’s your busiest day of the year and the website has crawled to a halt and finally crashed… and it was all because you did not understand how MongoDB uses memory and left your system open to cluster instability, poor performance, and unpredictable behavior. Understanding how MongoDB uses memory and planning for its use can […]
Are you thinking about deploying MongoDB? Is it the right choice for you? Choosing a database is an important step when designing an application. A wrong choice can have a negative impact on your organization in terms of development and maintenance. Also, the wrong choice can lead to poor performance. Generally speaking, any kind of […]
Whichever way you installed Percona Monitoring and Management 2 (PMM2), using the docker image or an OVF image for your supported virtualized environment, PMM2 enables, by default, two ports for the web connections: 80 for HTTP and 443 for HTTPS. Using HTTPS certificates are requested for encrypting the connection for better security. All the installation […]
We already presented a previous article on the index types available on MongoDB. MongoDB 4.4 was released a few months ago and introduced a new interesting feature: the hidden index. This feature is also available on Percona Server for MongoDB 4.4. In this article, we’ll see what it is. What is a Hidden Index A […]
MongoDB has a lot of possibilities for creating indexes. We have seen in previous articles some of the available index types and discussed explain() usage: Using Partial and Sparse Indexes in MongoDB MongoDB Index Types and MongoDB explain() (part 1) MongoDB: Investigate Queries with explain() and Index Usage (part 2) You can have a look […]
Recently I’ve been faced with an interesting challenge. How can I replicate data, in real-time, from DynamoDB to MongoDB? Why would I need real-time replication like that? For example: Running on MongoDB different queries relying on different indexes Having on MongoDB more fields or converted fields (you can do it during the replication) so you […]
This is the second part of a two-articles series. In the first part, we introduced the Common Table Expression (CTE), a new feature available on MySQL 8.0 as well as Percona Server for MySQL 8.0. In this article, we’ll present the Recursive Common Table Expression. SQL is generally poor at recursive structures, but it is […]
This blog is the first part of a two-articles series. In this article, I’m going to introduce the Common Table Expression (CTE), a new feature available on MySQL 8.0, as well as Percona Server for MySQL 8. What is a Common Table Expression? We can define a CTE as an alternative to a derived table. […]
We recently released Percona Backup for MongoDB(PBM) as GA. It’s our open source tool for taking a consistent backup of a running standalone mongod instance, a Replica Set, or a Sharded Cluster as well. The following articles can give you an overview of the tool: Avoid Vendor Lock-in with Percona Backup for MongoDB Percona Backup […]