Treat ETIMEDOUT as indicating a non-recoverable connection failure.

Add ETIMEDOUT to ALL_CONNECTION_FAILURE_ERRNOS' list of "errnos that
identify hard failure of a previously-established network connection".
While one could imagine that this is sometimes recoverable, the same
could be said of other entries such as ENETDOWN.

In support of this, handle ETIMEDOUT on par with other socket errors
in relevant infrastructure, such as TranslateSocketError().
(I made a couple of cosmetic adjustments in TranslateSocketError(),
too.)  The code now assumes that ETIMEDOUT is defined everywhere,
which it should be given that POSIX has required it since SUSv2.

Perhaps this should be back-patched, but I'm hesitant to do so given
the lack of previous complaints, and the hazard that there's a small
ABI break on Windows from redefining the symbol.  Even if we decide
to do that, it'd be prudent to let this bake awhile in HEAD first.

Jelte Fennema

Discussion: https://postgr.es/m/AM5PR83MB01782BFF2978505F6D6C559AF7AA9@AM5PR83MB0178.EURPRD83.prod.outlook.com

src/backend/port/win32/socket.c

@@ -47,8 +47,8 @@ int			pgwin32_noblock = 0;
  *
  * Note: where there is a direct correspondence between a WSAxxx error code
  * and a Berkeley error symbol, this mapping is actually a no-op, because
- * in win32.h we redefine the network-related Berkeley error symbols to have
- * the values of their WSAxxx counterparts.  The point of the switch is
+ * in win32_port.h we redefine the network-related Berkeley error symbols to
+ * have the values of their WSAxxx counterparts.  The point of the switch is
  * mostly to translate near-miss error codes into something that's sensible
  * in the Berkeley universe.
  */
@@ -141,10 +141,15 @@ TranslateSocketError(void)
 		case WSAEDISCON:
 			errno = ENOTCONN;
 			break;
+		case WSAETIMEDOUT:
+			errno = ETIMEDOUT;
+			break;
 		default:
 			ereport(NOTICE,
-					(errmsg_internal("unrecognized win32 socket error code: %d", WSAGetLastError())));
+					(errmsg_internal("unrecognized win32 socket error code: %d",
+									 WSAGetLastError())));
 			errno = EINVAL;
+			break;
 	}
 }
 

src/include/port.h

@@ -119,7 +119,8 @@ extern void pgfnames_cleanup(char **filenames);
 	case EHOSTUNREACH: \
 	case ENETDOWN: \
 	case ENETRESET: \
-	case ENETUNREACH
+	case ENETUNREACH: \
+	case ETIMEDOUT
 
 /* Portable locale initialization (in exec.c) */
 extern void set_pglocale_pgservice(const char *argv0, const char *app);

src/include/port/win32_port.h

@@ -381,6 +381,8 @@ extern int	_pgstat64(const char *name, struct stat *buf);
 #define ENETUNREACH WSAENETUNREACH
 #undef ENOTCONN
 #define ENOTCONN WSAENOTCONN
+#undef ETIMEDOUT
+#define ETIMEDOUT WSAETIMEDOUT
 
 /*
  * Locale stuff.

src/port/strerror.c

@@ -250,10 +250,8 @@ get_errno_symbol(int errnum)
 #endif
 		case ESRCH:
 			return "ESRCH";
-#ifdef ETIMEDOUT
 		case ETIMEDOUT:
 			return "ETIMEDOUT";
-#endif
 #ifdef ETXTBSY
 		case ETXTBSY:
 			return "ETXTBSY";