[5/5] kudu git commit: raft_consensus: avoid some unecessary allocations in hot path

[mp...@apache.org]

raft_consensus: avoid some unecessary allocations in hot path

In the stress cluster I noticed that UpdateConsensus does a lot of
allocation in LockForUpdate. In particular, it was constructing a
ConsensusStatusPB just to check whether it was currently a voter, and
that only to provide a log message. That PB has a lot of various strings
and other objects inside of it which caused unnecessary allocation.

We can already get this same information from the existing RaftConfigPB
object in ConsensusMeta, and a lot cheaper.

Change-Id: I75abcaaaed281e5ac1768ea3014064925db6c030
Reviewed-on: http://gerrit.cloudera.org:8080/5344
Tested-by: Kudu Jenkins
Reviewed-by: Mike Percy <mp...@apache.org>


Project: http://git-wip-us.apache.org/repos/asf/kudu/repo
Commit: http://git-wip-us.apache.org/repos/asf/kudu/commit/e14b8249
Tree: http://git-wip-us.apache.org/repos/asf/kudu/tree/e14b8249
Diff: http://git-wip-us.apache.org/repos/asf/kudu/diff/e14b8249

Branch: refs/heads/master
Commit: e14b82496da992c40af3fbf2c24a97f38b1d96cc
Parents: 4a8c86b
Author: Todd Lipcon <to...@apache.org>
Authored: Fri Dec 2 18:15:10 2016 -0800
Committer: Mike Percy <mp...@apache.org>
Committed: Mon Dec 5 17:39:32 2016 +0000

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 src/kudu/consensus/raft_consensus_state.cc | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)
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http://git-wip-us.apache.org/repos/asf/kudu/blob/e14b8249/src/kudu/consensus/raft_consensus_state.cc
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diff --git a/src/kudu/consensus/raft_consensus_state.cc b/src/kudu/consensus/raft_consensus_state.cc
index a0b38d4..af5943b 100644
--- a/src/kudu/consensus/raft_consensus_state.cc
+++ b/src/kudu/consensus/raft_consensus_state.cc
@@ -145,7 +145,7 @@ Status ReplicaState::LockForUpdate(UniqueLock* lock) const {
   if (PREDICT_FALSE(state_ != kRunning)) {
     return Status::IllegalState("Replica not in running state");
   }
-  if (!IsRaftConfigVoter(peer_uuid_, ConsensusStateUnlocked(CONSENSUS_CONFIG_ACTIVE).config())) {
+  if (!IsRaftConfigVoter(peer_uuid_, cmeta_->active_config())) {
     LOG_WITH_PREFIX_UNLOCKED(INFO) << "Allowing update even though not a member of the config";
   }
   lock->swap(l);