From: Tom Lane Date: Wed, 30 Sep 2015 02:06:59 +0000 (-0400) Subject: Small improvements in comments in async.c. X-Git-Url: http://git.postgresql.org/gitweb/?a=commitdiff_plain;h=6057f61b4d511d8321f295d827ced13809e5a1ae;p=users%2Frhaas%2Fpostgres.git Small improvements in comments in async.c. We seem to have lost a line somewhere along the way in the comment block that discusses async.c's locks, because it suddenly refers to "both locks" without previously having mentioned more than one. Add a sentence to make that read more sanely. Also, refer to the "pos of the slowest backend" not the "tail of the slowest backend", since we have no per-backend value called "tail". --- diff --git a/src/backend/commands/async.c b/src/backend/commands/async.c index 3b71174b82..91baede4e3 100644 --- a/src/backend/commands/async.c +++ b/src/backend/commands/async.c @@ -224,6 +224,7 @@ typedef struct QueueBackendStatus * When holding the lock in EXCLUSIVE mode, backends can inspect the entries * of other backends and also change the head and tail pointers. * + * AsyncCtlLock is used as the control lock for the pg_notify SLRU buffers. * In order to avoid deadlocks, whenever we need both locks, we always first * get AsyncQueueLock and then AsyncCtlLock. * @@ -234,7 +235,7 @@ typedef struct QueueBackendStatus typedef struct AsyncQueueControl { QueuePosition head; /* head points to the next free location */ - QueuePosition tail; /* the global tail is equivalent to the tail + QueuePosition tail; /* the global tail is equivalent to the pos * of the "slowest" backend */ TimestampTz lastQueueFillWarn; /* time of last queue-full msg */ QueueBackendStatus backend[FLEXIBLE_ARRAY_MEMBER];