MAJOR: backend: initial work towards connection reuse
In connect_server(), if we don't have a connection attached to the
stream-int, we first look into the server's idle_conns list and we
pick the first one there, we detach it from its owner if it had one.
If we used to have a connection, we close it.
This mechanism works well but doesn't scale : as servers increase,
the likeliness that the connection attached to the stream interface
doesn't match the server and gets closed increases.
diff --git a/src/backend.c b/src/backend.c
index 3c00acf..b31061a 100644
--- a/src/backend.c
+++ b/src/backend.c
@@ -1034,6 +1034,33 @@
if (srv_conn)
reuse = s->target == srv_conn->target;
+ if (srv && !reuse) {
+ if (srv_conn) {
+ srv_conn->owner = NULL;
+ si_release_endpoint(&s->si[1]);
+ srv_conn = NULL;
+ }
+
+ if ((s->be->options & PR_O_REUSE_MASK) == PR_O_REUSE_ALWS &&
+ !LIST_ISEMPTY(&srv->idle_conns)) {
+ /* We're going to have to pick the first connection
+ * from this pool and use it for our purposes. We may
+ * have to get rid of the current idle connection. It
+ * may move to another pool, but we know we're not
+ * interested in it.
+ */
+ /* pick first connection. We know there's at least one */
+ srv_conn = LIST_ELEM(srv->idle_conns.n, struct connection *, list);
+
+ LIST_DEL(&srv_conn->list);
+ LIST_INIT(&srv_conn->list);
+
+ si_detach_endpoint(srv_conn->owner);
+ si_attach_conn(&s->si[1], srv_conn);
+ reuse = 1;
+ }
+ }
+
if (reuse) {
/* Disable connection reuse if a dynamic source is used.
* As long as we don't share connections between servers,