postgres.git / summary / log / commit / refs

commit    5eca6cf99411bfd47f43fc742552c9a2ae459bc8
Author:   Robert Haas <rhaas@postgresql.org>
Date:     Fri Oct 23 02:01:11 2015 +0000
First released in: 9.6.0, 9.4.6, 9.5.0

    shm_mq: Repair breakage from previous commit.
    
    If the counterparty writes some data into the queue and then detaches,
    it's wrong to return SHM_MQ_DETACHED right away.  If we do that, we
    fail to read whatever was written.


 src/backend/storage/ipc/shm_mq.c | 6 ++++--
 1 file changed, 4 insertions(+), 2 deletions(-)

diff --git a/src/backend/storage/ipc/shm_mq.c b/src/backend/storage/ipc/shm_mq.c
index 296f0bda40c..c386b2207a1 100644
--- a/src/backend/storage/ipc/shm_mq.c
+++ b/src/backend/storage/ipc/shm_mq.c
@@ -405,10 +405,12 @@ shm_mq_receive(shm_mq_handle *mqh, Size *nbytesp, void **datap, bool nowait)
 	{
 		if (nowait)
 		{
-			if (shm_mq_counterparty_gone(mq, mqh->mqh_handle))
-				return SHM_MQ_DETACHED;
 			if (shm_mq_get_sender(mq) == NULL)
+			{
+				if (shm_mq_counterparty_gone(mq, mqh->mqh_handle))
+					return SHM_MQ_DETACHED;
 				return SHM_MQ_WOULD_BLOCK;
+			}
 		}
 		else if (!shm_mq_wait_internal(mq, &mq->mq_sender, mqh->mqh_handle)
 				 && shm_mq_get_sender(mq) == NULL)


[parent: 87abcb4ebd48]