Provide ConnectionProvider configuration for limiting the number of the connection pools

[violetagg]

This is a follow up issue for #3315 (comment)

[cloudzhou]

@violetagg when read from

https://projectreactor.io/docs/netty/release/api/reactor/netty/resources/ConnectionProvider.htm
Build a ConnectionProvider to cache and reuse a fixed maximum number of Connection.

but here https://projectreactor.io/docs/netty/1.2.0-M4/reference/tcp-client.html
Connections used by the TcpClient are never returned to the pool, but closed. When a connection is closed, a slot is freed in the pool and thus a new connection can be opened when needed.

so, how can ConnectionProvider reuse connection?
any one can help?

[violetagg]

@cloudzhou for TCP client you cannot reuse the connections, the connection pool is used to limit the number of the connections that you can open.

[cloudzhou]

so confused about that, TCP client and reuse connections is so common and important
the default implement need to pooled and reuse connections as base usage

[violetagg]

@cloudzhou as we pointed in the documentation
https://projectreactor.io/docs/netty/1.2.0-M4/reference/tcp-client.html#connection-pool
we don't know what protocol is used on top of TCP and whether the connections are recycled and ready to be reused.

[cloudzhou]

so is there a recommend way to pooled and reuse the connection?
some document or open source code demo?

[violetagg]

@cloudzhou Take a look at R2DBC pool https://github.com/r2dbc/r2dbc-pool (it uses TcpClient)

If you have more questions let's continue on Gitter