Don't send protocol messages to a shm_mq that no longer exists.
Commit 2bd9e412f92bc6a68f3e8bcb18e04955cc35001d introduced a mechanism
for relaying protocol messages from a background worker to another
backend via a shm_mq. However, there was no provision for shutting
down the communication channel. Therefore, a protocol message sent
late in the shutdown sequence, such as a DEBUG message resulting from
cranking up log_min_messages, could crash the server. To fix, install
an on_dsm_detach callback that disables sending messages to the shm_mq
when the associated DSM is detached.
Branch
------
REL9_5_STABLE
Details
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http://git.postgresql.org/pg/commitdiff/26981d292758c6ee9185332e4abc990ff19c81a2
Modified Files
--------------
src/backend/access/transam/parallel.c | 2 +-
src/backend/libpq/pqmq.c | 28 ++++++++++++++++++++++++++--
src/backend/storage/ipc/shm_mq.c | 9 +++++++++
src/include/libpq/pqmq.h | 2 +-
src/include/storage/shm_mq.h | 3 +++
5 files changed, 40 insertions(+), 4 deletions(-)
