"Persistent connection" in this context means, that the communicating sockets on each side are set up and showing up as "ESTABLISHED" in the network connections table, which means, the server has done an accept(), just sits there and is ready to read from the socket whatever the client may tell it.

Persistent means also that there's no shutdown of the connection after some talk or after some idle time, so whenever a request comes in to the dispatching server, it can query the database nodes without having to set up the connection anew with all overhead of socket allocating, listen, bind, accept calls, SYN,SYN-ACK,ACK handshake and so on. Pretty much like a "leased line" vs. "dialup connection".

--shmem 

_($_=" "x(1<<5)."?\n".q·/)Oo.  G°\        /
                              /\_¯/(q    /
----------------------------  \__(m.====·.(_("always off the crowd"))."·
");sub _{s./.($e="'Itrs `mnsgdq Gdbj O`qkdq")=~y/"-y/#-z/;$e.e && print}

In reply to Re^3: Rapid inter-machine communication on internal network by shmem
in thread Rapid inter-machine communication on internal network by Anonymous Monk

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