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cleanoutServer Bug Fix (#6537) 

* Fixing bug: cleanoutServer will no longer add old leader as follower.

* Fixed rollback.
This commit is contained in:
Lars Maier 2018-09-21 10:16:14 +02:00 committed by Max Neunhöffer
parent 6db05b8b12
commit 5929cafaf9
7 changed files with 89 additions and 37 deletions
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4
arangod/Agency/CleanOutServer.cpp
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@ -389,6 +389,8 @@ bool CleanOutServer::scheduleMoveShards(std::shared_ptr<Builder>& trx) {
serversCopy.end());
}
bool isLeader = (found == 0);
// Among those a random destination:
std::string toServer;
if (serversCopy.empty()) {
@ -403,7 +405,7 @@ bool CleanOutServer::scheduleMoveShards(std::shared_ptr<Builder>& trx) {
// Schedule move into trx:
MoveShard(_snapshot, _agent, _jobId + "-" + std::to_string(sub++),
_jobId, database.first, collptr.first,
shard.first, _server, toServer, found == 0)
shard.first, _server, toServer, isLeader, false)
.create(trx);
}
}

42
arangod/Agency/MoveShard.cpp
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@ -30,6 +30,22 @@
using namespace arangodb;
using namespace arangodb::consensus;
MoveShard::MoveShard(Node const& snapshot, AgentInterface* agent,
std::string const& jobId, std::string const& creator,
std::string const& database,
std::string const& collection, std::string const& shard,
std::string const& from, std::string const& to,
bool isLeader, bool remainsFollower)
: Job(NOTFOUND, snapshot, agent, jobId, creator),
_database(database),
_collection(collection),
_shard(shard),
_from(id(from)),
_to(id(to)),
_isLeader(isLeader), // will be initialized properly when information known
_remainsFollower(remainsFollower)
{ }
MoveShard::MoveShard(Node const& snapshot, AgentInterface* agent,
std::string const& jobId, std::string const& creator,
std::string const& database,
@ -42,7 +58,8 @@ MoveShard::MoveShard(Node const& snapshot, AgentInterface* agent,
_shard(shard),
_from(id(from)),
_to(id(to)),
_isLeader(isLeader) // will be initialized properly when information known
_isLeader(isLeader), // will be initialized properly when information known
_remainsFollower(isLeader)
{ }
MoveShard::MoveShard(Node const& snapshot, AgentInterface* agent,
@ -57,6 +74,7 @@ MoveShard::MoveShard(Node const& snapshot, AgentInterface* agent,
auto tmp_to = _snapshot.hasAsString(path + "toServer");
auto tmp_shard = _snapshot.hasAsString(path + "shard");
auto tmp_isLeader = _snapshot.hasAsSlice(path + "isLeader");
auto tmp_remainsFollower = _snapshot.hasAsSlice(path + "remainsFollower");
auto tmp_creator = _snapshot.hasAsString(path + "creator");
if (tmp_database.second && tmp_collection.second && tmp_from.second && tmp_to.second
@ -67,6 +85,7 @@ MoveShard::MoveShard(Node const& snapshot, AgentInterface* agent,
_to = tmp_to.first;
_shard = tmp_shard.first;
_isLeader = tmp_isLeader.first.isTrue();
_remainsFollower = tmp_remainsFollower.second ? tmp_remainsFollower.first.isTrue() : _isLeader;
_creator = tmp_creator.first;
} else {
std::stringstream err;
@ -130,6 +149,7 @@ bool MoveShard::create(std::shared_ptr<VPackBuilder> envelope) {
_jb->add("fromServer", VPackValue(_from));
_jb->add("toServer", VPackValue(_to));
_jb->add("isLeader", VPackValue(_isLeader));
_jb->add("remainsFollower", VPackValue(_remainsFollower));
_jb->add("jobId", VPackValue(_jobId));
_jb->add("timeCreated", VPackValue(now));
}
@ -276,6 +296,11 @@ bool MoveShard::start() {
return false;
}
if (!_isLeader && _remainsFollower) {
finish("", "", false, "remainsFollower is invalid without isLeader");
return false;
}
// Compute group to move shards together:
std::vector<Job::shard_t> shardsLikeMe
= clones(_snapshot, _database, _collection, _shard);
@ -507,6 +532,7 @@ JOB_STATUS MoveShard::pendingLeader() {
trx.add(srv);
}
}
// add the old leader as follower in case of a rollback
trx.add(VPackValue(_from));
}
// Precondition: Plan still as it was
@ -545,7 +571,19 @@ JOB_STATUS MoveShard::pendingLeader() {
{ VPackObjectBuilder trxObject(&trx);
VPackObjectBuilder preObject(&pre);
doForAllShards(_snapshot, _database, shardsLikeMe,
[&pre](Slice plan, Slice current, std::string& planPath) {
[&trx, &pre, this](Slice plan, Slice current, std::string& planPath) {
if (!_remainsFollower) {
// Remove _from from the list of follower
trx.add(VPackValue(planPath));
{ VPackArrayBuilder guard(&trx);
for (auto const& srv : VPackArrayIterator(plan)) {
if (!srv.isEqualString(_from)) {
trx.add(srv);
}
}
}
}
// Precondition: Plan still as it was
pre.add(VPackValue(planPath));
{ VPackObjectBuilder guard(&pre);

11
arangod/Agency/MoveShard.h
View File

@ -32,6 +32,16 @@ namespace consensus {
struct MoveShard : public Job {
MoveShard(Node const& snapshot, AgentInterface* agent, std::string const& jobId,
std::string const& creator,
std::string const& database,
std::string const& collection,
std::string const& shard,
std::string const& from,
std::string const& to,
bool isLeader,
bool remainsFollower);
MoveShard(Node const& snapshot, AgentInterface* agent, std::string const& jobId,
std::string const& creator,
std::string const& database,
@ -61,6 +71,7 @@ struct MoveShard : public Job {
std::string _from;
std::string _to;
bool _isLeader;
bool _remainsFollower;
};
}
}

1
tests/Agency/CleanOutServerTest.cpp
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@ -66,6 +66,7 @@ VPackBuilder createMoveShardJob() {
builder.add("fromServer", VPackValue("test"));
builder.add("toServer", VPackValue("test2"));
builder.add("isLeader", VPackValue(true));
builder.add("remainsFollower", VPackValue(false));
builder.add("collection", VPackValue("test"));
builder.add("shard", VPackValue("s99"));
builder.add("creator", VPackValue("unittest"));

2
tests/Agency/FailedFollowerTest.cpp
View File

@ -429,7 +429,7 @@ SECTION("abort any moveShard job blocking the shard and start") {
AgentInterface &moveShardAgent = moveShardMockAgent.get();
auto moveShard = MoveShard(
baseStructure(PREFIX), &moveShardAgent, "2", "strunz", DATABASE,
COLLECTION, SHARD, SHARD_LEADER, FREE_SERVER, true);
COLLECTION, SHARD, SHARD_LEADER, FREE_SERVER, true, true);
moveShard.create();
std::string jobId = "1";

2
tests/Agency/FailedLeaderTest.cpp
View File

@ -466,7 +466,7 @@ SECTION("abort any moveShard job blocking the shard and start") {
AgentInterface &moveShardAgent = moveShardMockAgent.get();
auto moveShard = MoveShard(
baseStructure("arango"), &moveShardAgent, "2", "strunz", DATABASE,
COLLECTION, SHARD, SHARD_LEADER, FREE_SERVER, true);
COLLECTION, SHARD, SHARD_LEADER, FREE_SERVER, true, true);
moveShard.create();
std::string jobId = "1";