vitalif
/
etcd
1
0
Fork 0
Code Issues Pull Requests Releases Wiki Activity

Merge pull request #8107 from heyitsanthony/lock-faster 

concurrency: fetch current lock holder when creating waitlist key
release-3.3
Anthony Romano 2017-06-15 15:12:08 -07:00 committed by GitHub
parent 037e33e833 f5b96991a1
commit 099952136a
1 changed files with 9 additions and 1 deletions
Show Stats Download Patch File Download Diff File Expand all files Collapse all files

10
clientv3/concurrency/mutex.go
View File

@ -49,7 +49,9 @@ func (m *Mutex) Lock(ctx context.Context) error {
put := v3.OpPut(m.myKey, "", v3.WithLease(s.Lease()))
// reuse key in case this session already holds the lock
get := v3.OpGet(m.myKey)
resp, err := client.Txn(ctx).If(cmp).Then(put).Else(get).Commit()
// fetch current holder to complete uncontended path with only one RPC
getOwner := v3.OpGet(m.pfx, v3.WithFirstCreate()...)
resp, err := client.Txn(ctx).If(cmp).Then(put, getOwner).Else(get, getOwner).Commit()
if err != nil {
return err
}
@ -57,6 +59,12 @@ func (m *Mutex) Lock(ctx context.Context) error {
if !resp.Succeeded {
m.myRev = resp.Responses[0].GetResponseRange().Kvs[0].CreateRevision
}
// if no key on prefix / the minimum rev is key, already hold the lock
ownerKey := resp.Responses[1].GetResponseRange().Kvs
if len(ownerKey) == 0 || ownerKey[0].CreateRevision == m.myRev {
m.hdr = resp.Header
return nil
}
// wait for deletion revisions prior to myKey
hdr, werr := waitDeletes(ctx, client, m.pfx, m.myRev-1)