In Windows pg_dump, ensure idle workers will shut down during error exit.

tglsfdc · tglsfdc · commit df8d2d8c42c5 · 2016-05-26T10:50:30.000-04:00
The Windows coding of ShutdownWorkersHard() thought that setting termEvent
was sufficient to make workers exit after an error.  But that only helps
if a worker is busy and passes through checkAborting().  An idle worker
will just sit, resulting in pg_dump failing to exit until the user gives up
and hits control-C.  We should close the write end of the command pipe
so that idle workers will see socket EOF and exit, as the Unix coding was
already doing.

Back-patch to 9.3 where parallel pg_dump was introduced.

Kyotaro Horiguchi
diff --git a/src/bin/pg_dump/parallel.c b/src/bin/pg_dump/parallel.c
@@ -300,28 +300,26 @@ checkAborting(ArchiveHandle *AH)
 }
 
 /*
- * Shut down any remaining workers, this has an implicit do_wait == true.
- *
- * The fastest way we can make the workers terminate gracefully is when
- * they are listening for new commands and we just tell them to terminate.
+ * Shut down any remaining workers, waiting for them to finish.
  */
 static void
 ShutdownWorkersHard(ParallelState *pstate)
 {
-#ifndef WIN32
 	int			i;
 
 	/*
-	 * Close our write end of the sockets so that the workers know they can
-	 * exit.
+	 * Close our write end of the sockets so that any workers waiting for
+	 * commands know they can exit.
 	 */
 	for (i = 0; i < pstate->numWorkers; i++)
 		closesocket(pstate->parallelSlot[i].pipeWrite);
 
+#ifndef WIN32
+	/* On non-Windows, send SIGTERM to abort commands-in-progress. */
 	for (i = 0; i < pstate->numWorkers; i++)
 		kill(pstate->parallelSlot[i].pid, SIGTERM);
 #else
-	/* The workers monitor this event via checkAborting(). */
+	/* Non-idle workers monitor this event via checkAborting(). */
 	SetEvent(termEvent);
 #endif
 
