Articles tagged with
mongodb
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.
20 Dec 2021
A new version of MongoDB, 5.0, has been recently launched. The list of changes included one that I found particularly interesting: the time series collections. It is a method of effective storing and processing of time-ordered value series. In this article we will verify whether the processing of time series is really as fast as promised by the authors.
18 Oct 2021
One of the key elements ensuring efficient operation of the services we work on every day at
Allegro is fast responses from the database.
We spend a lot of time to properly model the data so that storing and querying take as little time as possible.
You can read more about why good schema design is important in one of my earlier
posts.
It’s also equally important to make sure that all queries are covered with indexes of the correct type whenever
possible. Indexes are used to quickly search the database and under certain conditions even allow results to be
returned directly from the index, without the need to access the data itself. However, indexes are not
all the same and it’s important to learn more about their different types in order to make the right choices later on.
14 Jan 2021
So I was tuning one of our services in order to speed up some MongoDB queries. Incidentally, my attention was caught by
the size of one of the collections that contains archived objects and therefore is rarely used. Unfortunately I wasn’t
able to reduce the size of the documents stored there, but I started to wonder: is it possible to store the same data
in a more compact way? Mongo stores JSON that allows many different ways of expressing similar data, so there seems
to be room for improvements.
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.
28 Apr 2015
You might have read a recent post by our developers concerning performance analysis tools and its follow up concerning sysdig.
In the database world these tools come handy almost everyday. In this blog post
I will show you a case where I have put tools to action diagnosing a MongoDB issue.
