From 8f82badc23947dc3350fb43474a4ad20a81cb703 Mon Sep 17 00:00:00 2001
From: =?UTF-8?q?Pavel=20Czern=C3=BD?= <pczerny@opennebula.systems>
Date: Thu, 8 Oct 2020 16:22:10 +0200
Subject: [PATCH] B #5094: Fix DB reconnect (#304)

* B #5094: Improve MySQL reconnect

* B #5094: PostgreSQL reconnect
---
 src/sql/MySqlDB.cc      |  3 +++
 src/sql/PostgreSqlDB.cc | 23 +++++++++++++++++++++++
 2 files changed, 26 insertions(+)

diff --git a/src/sql/MySqlDB.cc b/src/sql/MySqlDB.cc
index a1100f4c09..02216342f3 100644
--- a/src/sql/MySqlDB.cc
+++ b/src/sql/MySqlDB.cc
@@ -202,6 +202,9 @@ MySqlDB::MySqlDB(const string& s, int p, const string& u, const string& _p,
     {
         connections[i] = mysql_init(NULL);
 
+        bool reconnect = true;
+        mysql_options(connections[i], MYSQL_OPT_RECONNECT, &reconnect);
+
         rc = mysql_real_connect(connections[i], server.c_str(), user.c_str(),
                 password.c_str(), 0, port, NULL, 0);
 
diff --git a/src/sql/PostgreSqlDB.cc b/src/sql/PostgreSqlDB.cc
index c826496d25..b9ea42eaa1 100644
--- a/src/sql/PostgreSqlDB.cc
+++ b/src/sql/PostgreSqlDB.cc
@@ -163,6 +163,29 @@ int PostgreSqlDB::exec_ext(std::ostringstream& cmd, Callbackable *obj, bool quie
 
     PGresult* res = PQexec(conn, c_str);
 
+    if ( PQstatus(conn) == CONNECTION_BAD )
+    {
+        PQreset(conn);
+
+        if ( PQstatus(conn) == CONNECTION_BAD )
+        {
+            NebulaLog::error("ONE", "Lost connection to DB, unable to reconnect");
+
+            PQclear(res);
+            free_db_connection(conn);
+
+            return SqlDB::CONNECTION;
+        }
+        else
+        {
+            NebulaLog::info("ONE", "Succesfully reconnected to DB");
+
+            // Re-execute the query
+            PQclear(res);
+            res = PQexec(conn, c_str);
+        }
+    }
+
     if ( PQresultStatus(res) != PGRES_COMMAND_OK &&
          PQresultStatus(res) != PGRES_TUPLES_OK )
     {