BUG/MINOR: tcpcheck: Disable QUICKACK only if data should be sent after connect
It is only a real problem for agent-checks when there is no agent string to
send. The condition to disable TCP_QUICKACK was only based on the action
type following the connect one. But it is not always accurate. indeed, for
agent-checks, there is always a SEND action. But if there is no "agent-send"
string defined, nothing is sent. In this case, this adds 200ms of latency
with no reason.
To fix the bug, a flag is now used on the CONNECT action to instruct there
are data that should be sent after the connect. For health-checks, this flag
is set if the action following the connect is a SEND action. For
agent-checks, it is set if an "agent-send" string is defined.
This patch should fix the issue #1836. It must be backported as far as 2.2.
diff --git a/src/check.c b/src/check.c
index efca99c..5a6ee08 100644
--- a/src/check.c
+++ b/src/check.c
@@ -1688,6 +1688,13 @@
LIST_INSERT(srv->agent.tcpcheck_rules->list, &chk->list);
}
+ /* <chk> is always defined here and it is a CONNECT action. If there is
+ * a preset variable, it means there is an agent string defined and data
+ * will be sent after the connect.
+ */
+ if (!LIST_ISEMPTY(&srv->agent.tcpcheck_rules->preset_vars))
+ chk->connect.options |= TCPCHK_OPT_HAS_DATA;
+
err = init_check(&srv->agent, PR_O2_TCPCHK_CHK);
if (err) {