10k DB connections
consume up to 21G of memory, which only accounts for 10% of
the server's memory in our env and will not cause OOM risk.
I think that's a lot and I would size it differently if it were my
setup.
The calculation only refers to the working memory that the
Connections roughly use. Not included in this calculation is, for
example, the buffer pool of the database itself.
In most cases, there are also processes that could use a lot of
memory outside the database itself.
RabbitMQ
The maximum number of
RabbitMQ connections is 20000, which is obtained by test in
the 3000 node environment.
That is
interesting. What was the limiting factor? Usually the number of
available file descriptors is significantly higher for the
RabbitMQ process.
(see /proc/<pid>/limits)
Incidentally, I have had good experiences with RabbitMQ Perftest
during performance tests these days.
(https://perftest.rabbitmq.com/)