I have noticed data is gathered per month in seperate tables, for each new month a new table. Is it common that Matomo creates an ever growing list of tables? Can this lead to database problems longterm? OK, I just found MySQL supports up to 4.000.000.000 tables so that won’t be the issue in my lifetime, but will data be summarized at one point?
I found that tables were created for 2017-2025 too, even though I only started using Matomo a while ago.. What is up with those tables?
Hey, yeah I’ve actually seen this kind of thing before with analytics setups, so I get why it looks a bit scary at first 
What you’re seeing is basically how Matomo structures data — it often splits stats into monthly tables (archive style), so over time it feels like “endless tables” even if the data size isn’t crazy.
I faced something similar when I set up Matomo for a client project, and I also thought the DB was exploding. But in reality it’s more about segmentation than actual bloat.
What helped me understand/handle it:
Those old year tables (like 2017–2025) can exist as “pre-created archive structure”, not necessarily active data
Make sure archiving is enabled properly, otherwise it keeps generating on demand
Run occasional DB optimization / check Matomo archive settings so it doesn’t keep unnecessary temp growth
Not sure if it helps, but I stopped worrying once I realized Matomo is designed like this, not broken 
That’s what I figured, but it was very unclear why there were tables for 2017-2025 and not just from 202603 on. For 2025 the tables for February, March and April are missing. That got my thinking data will be summarized over time and thus deleting obsolete tables, but this is not the case?
I assume all is set up correctly, but haven’t really touched the settings very in depth as all worked fine out of the box.