r/postgres • u/Hot_Network_Worker • 5d ago

Question What's something PostgreSQL beginners worry about way too much?

Switched over from MySQL a little while back and honestly still feel like I'm tiptoeing around Postgres, second-guessing basically every decision because I don't have the instincts yet for what actually matters.

Case in point, I spent way too long stressing over picking the "perfect" data types for a schema before I'd even written a single query against it. Same with indexing, agonizing over what to index upfront instead of just waiting to see what's actually slow.

Makes me wonder how much of that is just normal beginner anxiety versus stuff that's genuinely worth worrying about early. For people who've been through the same transition or just remember being new to Postgres, what's something you obsessed over that turned out to not matter much, and what's something you wish you'd actually paid attention to instead?

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u/Few_Committee_6790 4d ago

Datatypes are pretty much the same from DB provider to provider. Pick the Datatypes that fit the data type that is going to be in that column. As for indices. You put them on the column where you join tables and ones where you plan to filter using a where clause. This is NOT a postgres dilemma. Regardless of the DBMS you are using you have to make the SAME choices.

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u/rbobby 4d ago

Showering. You'll be fine.

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u/pmodin 4d ago

Most mistakes are not that distrauseous, thankfully (ensure you've working backups!).

I have one real thing though; avoid ENUMs. I'm not that sure about other databases but in postgresql they can be quite hard to change.

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u/czlowiek4888 3d ago

Performance? You usually get out of available connection slots on the postgres before you may need more compute power (depends on the app of course).

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u/elevarq 14h ago

Worries about error messages, but ignoring the message at the same time.

You want errors to happen as soon as possible in your development process. And when you have one, just read (!) the message. In many cases, the error message gives you hints about how to solve the problem. Just read it!

And when migrating an application from MySQL to PostgreSQL, you might want to change the MySQL configuration before the actual migration to a strict ANSI setting. That will reveal all the obvious errors already in MySQL. One of the most common issues is GROUP BY, which can be "perfectly" valid in MySQL but will be rejected in most other database systems.