If the inner function that handles the open of storage and cache
fails, we close the fragment. If we closeStorage() before that,
then we can try to close the storage again, which causes a panic
when we try to mark the generation as Done again.
I was going to set f.gen = nil after marking it done, but I'm
not feeling safe about that -- there's too many places where
we check things about f.gen, and it seems unsafe. The generation
code should be removed at some point, because it all exists
as a workaround for not having any way to detect when reads are
"done", because we didn't want to do something huge and intrusive,
like adding the Tx system and requiring transactions to get
closed.
Performance of tests on MacOS has been atrocious for a while, and
a lot of that is fsync, so we're trying to make that optional.
To test all of this, I modified RBF to panic if anything tried to
open an RBF database without disabling fsync, and ran the tests that
way, and tracked down the various places this could still happen.
There's a lot of places in our tree where we were creating
test holders which were not getting created with fsync disabled, which
results in a surprisingly large number of points at which we end
up calling fsync in tests, which makes tests much slower than they
need to be. There's also a bunch of places where the flags don't get
propagated correctly; for instance, storage.fsync didn't propagate
to the RBFConfig.
We add an "fsync enabled" flag to OpenTranslateStoreFunc, so we can
tell translation stores that we don't need syncing, so the server's
config can be passed on appropriately.
More of the test code that sets things up is correctly configuring
that flag by default.
We also change the barely-used bolt storage backend to support this as
well.
With this done, the only calls to fsync left in a run of `go test -short`
in the top-level directory are from the zap logger in etcd, and consumed
around 0.03 seconds. The overall impact is that `go test -short`
went from "takes enough more than 10 minutes that i don't know how long
it takes" to about 2.5 minutes.
boltdb has a couple of places where it fsyncs even when fsync is
disabled, this turns out to cost an amazing amount of time over
several thousand databases in our test run. In theory, they are
rare circumstances compared to updates; in practice, when you
open 256 partition key translation databases per server opened
and most of them never get written to, not so much.
In test runs, we open, and close, *huge* numbers of databases. Even
the single fsync on close for these ends up being expensive on some
hosts. *cough* Apple. At least in theory, writes delivered to the
disk are just as written whether or not you've hit fsync, as long
as the machine doesn't power off before getting to them. In the
circumstances where we disable fsync, that's fine.
Since we already have an fsync function for "fsync if it's
not disabled", use that.
We disable fsync more consistently in testing, including using
etcd's already-existing UnsafeNoFsync option to disable fsyncs
in the backing store boltdb used by etcd, to reduce runtime of
our tests on MacOS significantly.
Corresponding to this, we update etcd by one patch to pick
up a locally-invented patch which turns out to be nearly-identical
to the upstream fix for "disabling fsync makes boltdb not
even bother to write some data sometimes", which caused crashes
galore.
This adds the following test:
1. cluster comes up (node 1,2,3), status normal
2. Pause node 3
3. Insert keys making sure to filter out the keys that will go to the paused node
4. Wait for status to become degraded
5. Unpause node 3
6. Wait for status to get back to normal
7. Check that keys were replicated to all 3 nodes
