The suggested pattern for Raft proposals is that they be retried
periodically until they succeed. This turns out to be an issue
when a leader cannot commit entries because the leader will continue
to append re-proposed entries to its log without committing anything.
This can result in the uncommitted tail of a leader's log growing
without bound until it is able to commit entries.
This change add a safeguard to protect against this case where a
leader's log can grow without bound during loss of quorum scenarios.
It does so by introducing a new, optional ``MaxUncommittedEntriesSize
configuration. This config limits the max aggregate size of uncommitted
entries that may be appended to a leader's log. Once this limit
is exceeded, proposals will begin to return ErrProposalDropped
errors.
See cockroachdb/cockroach#27772
Convenient invariant:
- if werr == nil then lock is supposed to be locked at the moment.
While we could not be confident in stronger invariant ('is exactly locked'),
it were inconvenient that previous code could return `werr == nil` after
Mutex.Unlock.
It could happen when ctx is canceled/timeouted exactly after waitDeletes
successfully returned werr == nil and before `<-ctx.Done()` checked.
While such situation is very rare, it is still possible.
fixes#10111
We should allow etcd client use all of the available keepalive
client parameters as documented in this link,
https://godoc.org/google.golang.org/grpc/keepalive#ClientParameters
Currently in the etcd, by default PermitWithoutStream is set to
false, and user has no way to override it.
On the server side, we explicitely setting EnforcementPolicy
PermitWithoutStream to false and don't provide option to override it
to user but on the client side we should allow this option as
provided by the grpc.
When building tools on Win,it shows `.\main.go:68:12: assignment mismatch: 2 variables but 1 values`.The reason is the return variables not match the calling from `main.go` and i try to fix it.
Maintain existing error message for not-enough-args
Add "too many args" if too many args
Add more helpful error message if v2 syntax was used
New output:
```
sauer@host:~/dev/etcd$ ./bin/etcdctl --endpoints http://localhost:5001 member add
Error: member name not provided.
sauer@host:~/dev/etcd$ ./bin/etcdctl --endpoints http://localhost:5001 member add node2 node2
Error: too many arguments
sauer@host:~/dev/etcd$ ./bin/etcdctl --endpoints http://localhost:5001 member add node2 http://localhost:6002
Error: too many arguments, did you mean "--peer-urls http://localhost:6002"
sauer@host:~/dev/etcd$ ./bin/etcdctl --endpoints http://localhost:5001 member add http://localhost:6002 node2
Error: too many arguments, did you mean "--peer-urls http://localhost:6002"
```
The previous logic was erroneously setting Ready.MustSync to true when
the hard state had not changed because we were comparing an empty hard
state to the previous hard state. In combination with another misfeature
in CockroachDB (unnecessary writing of empty batches), this was causing
a steady stream of synchronous writes to disk.
