Description:
# MySQL Router <= 2.1.4 treats `connect_timeout` as second
## Routing module uses `select` with `timeout_val` argument for timeout(struct timeval).
- https://github.com/mysql/mysql-router/blob/release-2.1.4/src/routing/src/routing.cc#L174
## `timeout_val` is set tv_sec = connect_timeout
- https://github.com/mysql/mysql-router/blob/release-2.1.4/src/routing/src/routing.cc#L153-L...
# MySQL Router = 2.1.5 treats `connect_timeout` as **millisecond**
## 2.1.5 uses `connect_non_blocking_wait` new function
- https://github.com/mysql/mysql-router/blob/release-2.1.5/src/routing/src/routing.cc#L203
## `connect_non_blocking_wait` uses `poll` function and its timeout argument is `timeout_ms` (int)
- https://github.com/mysql/mysql-router/blob/release-2.1.5/src/routing/src/routing.cc#L125
## `timeout_ms` is passed `connect_timeout` without any modification
- https://github.com/mysql/mysql-router/blob/release-2.1.5/src/routing/src/routing.cc#L203
### backtrace
```
(gdb) bt
+bt
#0 routing::SocketOperations::connect_non_blocking_wait (
this=0x7fe2232b37d8 <routing::SocketOperations::instance()::instance_>, sock=6, timeout_ms=1)
at /usr/src/debug/mysql-router-2.1.5/src/routing/src/routing.cc:120
#1 0x00007fe2230a87c0 in routing::SocketOperations::get_mysql_socket (
this=0x7fe2232b37d8 <routing::SocketOperations::instance()::instance_>, addr=
{addr = "mytest.cvmhu33tf2s1.us-east-1.rds.amazonaws.com", port = 3306, ip_family_ = mysqlrouter::TCPAddress::IPV4},
connect_timeout=connect_timeout@entry=1, log=log@entry=true)
at /usr/src/debug/mysql-router-2.1.5/src/routing/src/routing.cc:203
#2 0x00007fe2230a3d37 in RouteDestination::get_mysql_socket (this=this@entry=0x7fe21c000dc0, addr=
@0x7fe213ffec20: {addr = "mytest.cvmhu33tf2s1.us-east-1.rds.amazonaws.com", port = 3306, ip_family_ = mysqlrouter::TCPAddress::IPV4}, connect_timeout=connect_timeout@entry=1, log_errors=log_errors@entry=true)
at /usr/src/debug/mysql-router-2.1.5/src/routing/src/destination.cc:162
#3 0x00007fe2230a7cd4 in DestFirstAvailable::get_server_socket (this=0x7fe21c000dc0, connect_timeout=1,
error=0x7fe213ffecc8) at /usr/src/debug/mysql-router-2.1.5/src/routing/src/dest_first_available.cc:43
#4 0x00007fe2230a09df in MySQLRouting::routing_select_thread (this=0x7fe221c13c20, client=5)
at /usr/src/debug/mysql-router-2.1.5/src/routing/src/mysql_routing.cc:217
#5 0x00007fe2242612b0 in std::(anonymous namespace)::execute_native_thread_routine (__p=<optimized out>)
at ../../../../../libstdc++-v3/src/c++11/thread.cc:84
#6 0x00007fe2244bbe25 in start_thread (arg=0x7fe213fff700) at pthread_create.c:308
#7 0x00007fe2239c934d in clone () at ../sysdeps/unix/sysv/linux/x86_64/clone.S:113
```
After that, MySQL Router 2.1.5 fails to connect destination server by timeout over the Internet.
How to repeat:
1. Add routing into /etc/mysqlrouter/mysqlrouter.conf, `destinations` is over the Internet.
```
[routing:test]
bind_port= 13306
mode= read-write
destinations= xxxx:3306
```
2. Start MySQL Router and try to connect by mysql command-line client.
```
$ sudo systemctl start mysqlrouter
$ mysql -h127.0.0.1 -P13306
ERROR 2013 (HY000): Lost connection to MySQL server at 'reading initial communication packet', system error: 0
```
3. See /var/log/mysqlrouter/mysqlrouter.log
```
$ sudo less /var/log/mysqlrouter/mysqlrouter.log
2018-02-21 12:27:25 INFO [7fe221c14700] [routing:test] started: listening on 127.0.0.1:13306; read-write
2018-02-21 12:27:39 WARNING [7fe213fff700] Timeout reached trying to connect to MySQL Server xxxx:3306: Connection timed out
2018-02-21 12:27:48 INFO [7fe213fff700] [routing:test] fd=5 Pre-auth socket failure 127.0.0.1: client auth timed out
```
Suggested fix:
Get back `connect_timeout` as second value.
This means connect_non_blocking_wait function should receive 2nd argument(int timeout_ms) as second value(int timeout_sec), and pass `timeout_sec * 1000` to `poll` function.
I think this is **NOT Documentation Bug**.
This is too big imcompatibillity during 1 GA series minor upgrade.
