Enable auto reconnect for ER_CLIENT_INTERACTION_TIMEOUT

See also:
- https://dev.mysql.com/doc/relnotes/mysql/8.0/en/news-8-0-24.html#mysqld-8-0-24-connection-management
- https://dev.mysql.com/worklog/task/?id=12999
- https://bugs.mysql.com/bug.php?id=93240

dbdimp.c

@@ -4438,6 +4438,9 @@ int mysql_db_reconnect(SV* h)
   imp_dbh_t* imp_dbh;
   MYSQL save_socket;
 
+  if (DBIc_DBISTATE(imp_xxh)->debug >= 2)
+    PerlIO_printf(DBIc_LOGPIO(imp_xxh), "reconnecting\n");
+
   if (DBIc_TYPE(imp_xxh) == DBIt_ST)
   {
     imp_dbh = (imp_dbh_t*) DBIc_PARENT_COM(imp_xxh);
@@ -4457,16 +4460,23 @@ int mysql_db_reconnect(SV* h)
   }
 
   if (mysql_errno(imp_dbh->pmysql) != CR_SERVER_GONE_ERROR &&
-          mysql_errno(imp_dbh->pmysql) != CR_SERVER_LOST)
+          mysql_errno(imp_dbh->pmysql) != CR_SERVER_LOST &&
+          mysql_errno(imp_dbh->pmysql) != ER_CLIENT_INTERACTION_TIMEOUT) {
     /* Other error */
+    if (DBIc_DBISTATE(imp_xxh)->debug >= 2)
+      PerlIO_printf(DBIc_LOGPIO(imp_xxh), "Can't reconnect on unexpected error %d\n",
+          mysql_errno(imp_dbh->pmysql));
     return FALSE;
+  }
 
   if (!DBIc_has(imp_dbh, DBIcf_AutoCommit) || !imp_dbh->auto_reconnect)
   {
     /* We never reconnect if AutoCommit is turned off.
      * Otherwise we might get an inconsistent transaction
      * state.
      */
+    if (DBIc_DBISTATE(imp_xxh)->debug >= 2)
+      PerlIO_printf(DBIc_LOGPIO(imp_xxh), "Can't reconnect as AutoCommit is turned off\n");
     return FALSE;
   }
 

t/15reconnect.t

@@ -16,7 +16,7 @@ eval {$dbh = DBI->connect($test_dsn, $test_user, $test_password,
 if ($@) {
   plan skip_all => "no database connection";
 }
-plan tests => 28;
+plan tests => 34;
 
 for my $mysql_server_prepare (0, 1) {
 $dbh= DBI->connect("$test_dsn;mysql_server_prepare=$mysql_server_prepare;mysql_server_prepare_disable_fallback=1", $test_user, $test_password,
@@ -30,6 +30,11 @@ ok($dbh->{mysql_auto_reconnect} = 1, "enabling reconnect");
 
 ok($dbh->{AutoCommit} = 1, "enabling autocommit");
 
+ok ($dbh->do("SET SESSION wait_timeout=2"));
+sleep(3);
+ok($dbh->do("SELECT 1"), "implicitly reconnecting handle with 'do'");
+ok($dbh->{Active}, "checking for reactivated handle");
+
 ok($dbh->disconnect(), "disconnecting active handle");
 
 ok(!$dbh->{Active}, "checking for inactive handle");