As noticed in issue #23687, if we shut down Scylla while a paged read is
in progress - or even a paged read that the client had no intention of
ever resume it - the shutdown pauses for 10 seconds.
The problem was the stop() order - we must stop the "querier cache"
before we can close sstables - the "querier cache" is what holds paged
readers alive waiting for clients to resume those reads, and while a
reader is alive it holds on to sstables so they can't be closed. The
querier cache's querier_cache::default_entry_ttl is set to 10 seconds,
which is why the shutdown was un-paused after 10 seconds.
This fix in this patch is obvious: We need to stop the querier cache
(and have it release all the readers it was holding) before we close
the sstables.
Fixes#23687
Signed-off-by: Nadav Har'El <nyh@scylladb.com>
Closesscylladb/scylladb#23770
6db666a1c1