[tarantool-patches] Re: [PATCH v2 4/4] wal: delete old wal files when running out of disk space
- From: Vladimir Davydov <vdavydov.dev@xxxxxxxxx>
- To: Konstantin Osipov <kostja@xxxxxxxxxxxxx>
- Date: Wed, 24 Oct 2018 12:51:16 +0300
On Tue, Oct 23, 2018 at 09:46:45PM +0300, Konstantin Osipov wrote:
* Vladimir Davydov <vdavydov.dev@xxxxxxxxx> [18/10/23 20:30]:
+static void
+gc_process_wal_event(struct wal_watcher_msg *msg)
+{
+ if ((msg->events & WAL_EVENT_GC) == 0)
+ return;
GC is now subscribed to all events only to react to those *gc*
events which delete wal files in case of emergency.
Shouldn't gc ignore wal gc events which were initiated by
wal_collect_garbage() at least?
Why send wal_event_gc for these events?
Well, we could pass a mask of events a subscriber is interested in.
Come to think of it, this would look better IMO.
wal watcher api is an artefact from the times when we had no
cbus connection between wal and tx.
No, this isn't true. WAL watcher was introduced as a generic
notification channel built over cbus in the first place. Before
it was made available, we used inotify to track WAL directory
changes in relays.
Now you can send a direct message to gc. Why use wal watcher api at
all?
Because we already have a generic abstraction, and I think we'd better
use it instead of adding another wal-tx pipe to the wal_thread and
implementing home-brewed notifications on top of it.
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