Ich bin kein Datenbankexperte, aber ich kann versuchen, Ihre Fragen zu beantworten, was mein Verständnis ist.
1) Ist 45 p/Monat?
No, the max_connections is not per month but the number of concurrent
connections allowed simultaneously.
2) Kann jemand bitte erklären, was 1 Verbindung definiert? Ist es eine Abfrage an die Datenbank?
3) Wenn es eine Abfrage ist, was ist, wenn eine Abfrage 100 Werte zurückgibt? Werden diese als Verbindungen gezählt?
The value returned by the query doesn't matter. It can return as many values as it
like(you need to handle that in your code though). What happens in the code is that
you open a connection and then run a query after that you close that connection.
What happens between when the connection open and closes doesn't affect the number
of connection.
However you need to take care of other parameters while running a long query into a
database. As it could spike your CPU/memory utilization etc. but the number of
connection per query would still be 1.