diff options
| author | Tom Lane | 2017-08-31 19:10:24 +0000 |
|---|---|---|
| committer | Tom Lane | 2017-08-31 19:10:24 +0000 |
| commit | 6708e447efb5046c95bdcf900b6da97f56f97ae8 (patch) | |
| tree | e3d331eec9f26181d2a0983f303bd8eb49e9fea8 /src/include | |
| parent | 4b1dd62a257a469f92fef4f4cce37beab6c0b98b (diff) | |
Clean up shm_mq cleanup.
The logic around shm_mq_detach was a few bricks shy of a load, because
(contrary to the comments for shm_mq_attach) all it did was update the
shared shm_mq state. That left us leaking a bit of process-local
memory, but much worse, the on_dsm_detach callback for shm_mq_detach
was still armed. That means that whenever we ultimately detach from
the DSM segment, we'd run shm_mq_detach again for already-detached,
possibly long-dead queues. This accidentally fails to fail today,
because we only ever re-use a shm_mq's memory for another shm_mq, and
multiple detach attempts on the last such shm_mq are fairly harmless.
But it's gonna bite us someday, so let's clean it up.
To do that, change shm_mq_detach's API so it takes a shm_mq_handle
not the underlying shm_mq. This makes the callers simpler in most
cases anyway. Also fix a few places in parallel.c that were just
pfree'ing the handle structs rather than doing proper cleanup.
Back-patch to v10 because of the risk that the revenant shm_mq_detach
callbacks would cause a live bug sometime. Since this is an API
change, it's too late to do it in 9.6. (We could make a variant
patch that preserves API, but I'm not excited enough to do that.)
Discussion: https://postgr.es/m/8670.1504192177@sss.pgh.pa.us
Diffstat (limited to 'src/include')
| -rw-r--r-- | src/include/storage/shm_mq.h | 4 |
1 files changed, 2 insertions, 2 deletions
diff --git a/src/include/storage/shm_mq.h b/src/include/storage/shm_mq.h index 02a93e02222..7709efcc483 100644 --- a/src/include/storage/shm_mq.h +++ b/src/include/storage/shm_mq.h @@ -62,8 +62,8 @@ extern shm_mq_handle *shm_mq_attach(shm_mq *mq, dsm_segment *seg, /* Associate worker handle with shm_mq. */ extern void shm_mq_set_handle(shm_mq_handle *, BackgroundWorkerHandle *); -/* Break connection. */ -extern void shm_mq_detach(shm_mq *); +/* Break connection, release handle resources. */ +extern void shm_mq_detach(shm_mq_handle *mqh); /* Get the shm_mq from handle. */ extern shm_mq *shm_mq_get_queue(shm_mq_handle *mqh); |