Replace walsender's latch with the general shared latch.

Relying on the normal shared latch simplifies interrupt/signal
handling because we can rely on all signal handlers setting the proc
latch. That in turn allows us to avoid the use of
ImmediateInterruptOK, which arguably isn't correct because
WaitLatchOrSocket isn't declared to be immediately interruptible.

Also change sections that wait on the walsender's latch to notice
interrupts quicker/more reliably and make them more consistent with
each other.

This is part of a larger "get rid of ImmediateInterruptOK" series.

Discussion: 20150115020335.GZ5245@awork2.anarazel.de

1 files changed, 8 insertions, 2 deletions

diff --git a/src/backend/replication/basebackup.c b/src/backend/replication/basebackup.c
index 07030a2ef08..3058ce921b0 100644
--- a/src/backend/replication/basebackup.c
+++ b/src/backend/replication/basebackup.c
@@ -1294,15 +1294,21 @@ throttle(size_t increment)
 	/* Only sleep if the transfer is faster than it should be. */
 	if (sleep > 0)
 	{
-		ResetLatch(&MyWalSnd->latch);
+		ResetLatch(MyLatch);
+
+		/* We're eating a potentially set latch, so check for interrupts */
+		CHECK_FOR_INTERRUPTS();
 
 		/*
 		 * (TAR_SEND_SIZE / throttling_sample * elapsed_min_unit) should be
 		 * the maximum time to sleep. Thus the cast to long is safe.
 		 */
-		wait_result = WaitLatch(&MyWalSnd->latch,
+		wait_result = WaitLatch(MyLatch,
 							 WL_LATCH_SET | WL_TIMEOUT | WL_POSTMASTER_DEATH,
 								(long) (sleep / 1000));
+
+		if (wait_result & WL_LATCH_SET)
+			CHECK_FOR_INTERRUPTS();
 	}
 	else
 	{