Articles tagged with
nosql
14 Sep 2023
MongoDB is the most popular database used at Allegro. We have hundreds of MongoDB databases running on our on—premise servers.
In 2022 we decided that we need to migrate all our MongoDB databases
from existing shared clusters to new MongoDB clusters hosted on Kubernetes pods with separated resources.
To perform the migration of all databases we needed a tool for transfering all the data and keeping consistency between old and new databases.
That’s how mongo-migration-stream project was born.
21 Dec 2022
Let’s look at what transactions in MongoDB are and how they differ from SQL transactions.
04 Oct 2022
What would you say if we stored 1 000 records in a database, and the database claimed that there were only 998 of them? Or, if we created a database storing sets of values and in some cases the database would claim that some element was in that set, while in fact it was not? It definitely must be a bug, right? It turns out such behavior is not necessarily an error, as long as we use a database that implements probabilistic algorithms and data structures. In this post we will learn about two probability-based techniques, perform some experiments and consider when it is worth using a database that lies to us a bit.
29 Dec 2016
Understanding data model is sufficient to design good database schema in RDBMS (relational
database management system). Having this knowledge you are able to construct normalized tables, add appropriate
constraints and finally create indexes to speed up queries.
In the world of NoSQL there are no simple solutions, rules and answers. That’s why we can only talk about
patterns, tips and hints. MongoDB is not an exception. Besides the comprehension of stored data, deep
understanding of an access pattern, how data is searched, inserted and updated by an application is needed.
