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shm_mq: Repair breakage from previous commit.

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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.
This commit is contained in:
Robert Haas 2015-10-22 22:01:11 -04:00
parent 872101bede
commit a1480ec1d3
1 changed files with 4 additions and 2 deletions
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6
src/backend/storage/ipc/shm_mq.c
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@ -501,10 +501,12 @@ shm_mq_receive(shm_mq_handle *mqh, Size *nbytesp, void **datap, bool nowait)
{ {
if (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_get_sender(mq) == NULL)
{
if (shm_mq_counterparty_gone(mq, mqh->mqh_handle))
return SHM_MQ_DETACHED;
return SHM_MQ_WOULD_BLOCK; return SHM_MQ_WOULD_BLOCK;
}
} }
else if (!shm_mq_wait_internal(mq, &mq->mq_sender, mqh->mqh_handle) else if (!shm_mq_wait_internal(mq, &mq->mq_sender, mqh->mqh_handle)
&& shm_mq_get_sender(mq) == NULL) && shm_mq_get_sender(mq) == NULL)