From 6d8b2a4e9efa19e93d5cc3732ab7d00baf7566f1 Mon Sep 17 00:00:00 2001
From: Dan Goodliffe <dan@randomdan.homeip.net>
Date: Mon, 7 Dec 2015 14:15:26 +0000
Subject: Improve connection failure detection

---
 libpqpp/connection.cpp       |  4 +++-
 libpqpp/unittests/testpq.cpp | 38 ++++++++++++++++++++++++++++++++++++++
 2 files changed, 41 insertions(+), 1 deletion(-)

diff --git a/libpqpp/connection.cpp b/libpqpp/connection.cpp
index 57531e3..de3f189 100644
--- a/libpqpp/connection.cpp
+++ b/libpqpp/connection.cpp
@@ -3,6 +3,7 @@
 #include "selectcommand.h"
 #include "modifycommand.h"
 #include <unistd.h>
+#include <poll.h>
 #include <boost/assert.hpp>
 
 NAMEDFACTORY("postgresql", PQ::Connection, DB::ConnectionFactory);
@@ -108,7 +109,8 @@ PQ::Connection::bulkUpdateStyle() const
 void
 PQ::Connection::ping() const
 {
-	if (PQstatus(conn) != CONNECTION_OK) {
+	struct pollfd fd { PQsocket(conn), POLLRDHUP | POLLERR | POLLHUP | POLLNVAL, 0 };
+	if (PQstatus(conn) != CONNECTION_OK || poll(&fd, 1, 1)) {
 		if (inTx()) {
 			throw ConnectionError(conn);
 		}
diff --git a/libpqpp/unittests/testpq.cpp b/libpqpp/unittests/testpq.cpp
index 002b18c..3f55c63 100644
--- a/libpqpp/unittests/testpq.cpp
+++ b/libpqpp/unittests/testpq.cpp
@@ -169,6 +169,44 @@ BOOST_AUTO_TEST_CASE( insertId )
 	delete ro;
 }
 
+BOOST_AUTO_TEST_CASE( reconnect )
+{
+	auto ro = DB::MockDatabase::openConnectionTo("pqmock");
+	auto rok = DB::MockDatabase::openConnectionTo("pqmock");
+	auto pqconn = dynamic_cast<PQ::Connection *>(ro);
+	int pid1 = PQbackendPID(pqconn->conn);
+	BOOST_REQUIRE(pid1);
+	ro->ping();
+	auto kil = rok->newModifyCommand("SELECT pg_terminate_backend(?)");
+	kil->bindParamI(0, pid1);
+	kil->execute();
+	delete kil;
+	ro->ping();
+	int pid2 = PQbackendPID(pqconn->conn);
+	BOOST_REQUIRE(pid2);
+	BOOST_REQUIRE(pid1 != pid2);
+	delete ro;
+	delete rok;
+}
+
+BOOST_AUTO_TEST_CASE( reconnectInTx )
+{
+	auto ro = DB::MockDatabase::openConnectionTo("pqmock");
+	auto rok = DB::MockDatabase::openConnectionTo("pqmock");
+	auto pqconn = dynamic_cast<PQ::Connection *>(ro);
+	int pid1 = PQbackendPID(pqconn->conn);
+	BOOST_REQUIRE(pid1);
+	ro->ping();
+	ro->beginTx();
+	auto kil = rok->newModifyCommand("SELECT pg_terminate_backend(?)");
+	kil->bindParamI(0, pid1);
+	kil->execute();
+	delete kil;
+	BOOST_REQUIRE_THROW(ro->ping(), PQ::ConnectionError);
+	delete ro;
+	delete rok;
+}
+
 BOOST_AUTO_TEST_SUITE_END();
 
 BOOST_AUTO_TEST_CASE( connfail )
-- 
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