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dbe31e3f65
This patch adds a new member <curr_sess_idle_conns> on the server. It serves as a counter of idle connections attached on a session instead of regular idle/safe trees. This is used only for private connections. The objective is to provide a method to detect if there is idle connections still referencing a server. This will be particularly useful to ensure that a server is removable. Currently, this is not yet necessary as idle connections are directly freed via "del server" handler under thread isolation. However, this procedure will be replaced by an asynchronous mechanism outside of thread isolation. Careful: connections attached to a session but not idle will not be accounted by this counter. These connections can still be detected via srv_has_streams() so "del server" will be safe. This counter is maintain during the whole lifetime of a private connection. This is mandatory to guarantee "del server" safety and is conform with other idle server counters. What this means it that decrement is performed only when the connection transitions from idle to in use, or just prior to its deletion. For the first case, this is covered by session_get_conn(). The second case is trickier. It cannot be done via session_unown_conn() as a private connection may still live a little longer after its removal from session, most notably when scheduled for idle purging. Thus, conn_free() has been adjusted to handle the final decrement. Now, conn_backend_deinit() is also called for private connections if CO_FL_SESS_IDLE flag is present. This results in a call to srv_release_conn() which is responsible to decrement server idle counters.