How to work with geometry types in Postgres?

Question

PostgreSQL

Hello!
I have a database in Postgres. There was a need to work with geographic data.
Of the necessary:
​​1. creation of polygons;
2. checking the presence of a point in the polygon;
3. finding the nearest polygon to a point (or, in extreme cases, the nearest point to a point).
On the first 2 points I found documentation. I can't find anything for point 3.
I came across some PostGIS, but I'm afraid to install extensions on a working database, as well as I'm afraid of further possible problems when updating.
Is it possible to solve the problem using standard tools, or is it generally worth using another tool for geodata?
The database will not be large, up to 100,000 records.
Thank you!

Answer 1

install PostGIS, it covers all three points. And don't worry, you shouldn't break your base with them.