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24-3: Fix excessive read latency during and after shard splits #11061

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Merged
merged 1 commit into from
Oct 30, 2024
Merged

24-3: Fix excessive read latency during and after shard splits #11061

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10 changes: 10 additions & 0 deletions ydb/core/tx/datashard/datashard__read_iterator.cpp
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Original file line number Diff line number Diff line change
Expand Up @@ -2645,6 +2645,16 @@ void TDataShard::Handle(TEvDataShard::TEvRead::TPtr& ev, const TActorContext& ct
return;
}

if (State == TShardState::PreOffline ||
State == TShardState::Offline)
{
replyWithError(
Ydb::StatusIds::NOT_FOUND,
TStringBuilder() << "Shard " << TabletID() << " finished splitting/merging"
<< " (node# " << SelfId().NodeId() << " state# " << DatashardStateName(State) << ")");
return;
}

if (!IsStateNewReadAllowed()) {
replyWithError(
Ydb::StatusIds::OVERLOADED,
Expand Down
8 changes: 6 additions & 2 deletions ydb/core/tx/datashard/datashard_ut_common_kqp.h
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Original file line number Diff line number Diff line change
Expand Up @@ -186,10 +186,14 @@ namespace NKqpHelpers {
return KqpSimpleExec(runtime, query, true, database);
}

inline TString KqpSimpleBegin(TTestActorRuntime& runtime, TString& sessionId, TString& txId, const TString& query) {
inline auto KqpSimpleBeginSend(TTestActorRuntime& runtime, TString& sessionId, const TString& query) {
sessionId = CreateSessionRPC(runtime);
return SendRequest(runtime, MakeSimpleRequestRPC(query, sessionId, /* txId */ {}, false /* commitTx */));
}

inline TString KqpSimpleBegin(TTestActorRuntime& runtime, TString& sessionId, TString& txId, const TString& query) {
txId.clear();
auto response = AwaitResponse(runtime, SendRequest(runtime, MakeSimpleRequestRPC(query, sessionId, txId, false /* commitTx */)));
auto response = AwaitResponse(runtime, KqpSimpleBeginSend(runtime, sessionId, query));
if (response.operation().status() != Ydb::StatusIds::SUCCESS) {
return TStringBuilder() << "ERROR: " << response.operation().status();
}
Expand Down
72 changes: 69 additions & 3 deletions ydb/core/tx/datashard/datashard_ut_read_iterator.cpp
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Expand Up @@ -3970,7 +3970,7 @@ Y_UNIT_TEST_SUITE(DataShardReadIterator) {
Y_UNIT_TEST(HandleMvccGoneInContinue) {
// TODO
}
};
}

Y_UNIT_TEST_SUITE(DataShardReadIteratorSysTables) {
Y_UNIT_TEST(ShouldRead) {
Expand Down Expand Up @@ -4054,7 +4054,7 @@ Y_UNIT_TEST_SUITE(DataShardReadIteratorSysTables) {

UNIT_ASSERT_VALUES_EQUAL(record.GetStatus().GetCode(), Ydb::StatusIds::UNSUPPORTED);
}
};
}

Y_UNIT_TEST_SUITE(DataShardReadIteratorState) {
Y_UNIT_TEST(ShouldCalculateQuota) {
Expand Down Expand Up @@ -4105,7 +4105,7 @@ Y_UNIT_TEST_SUITE(DataShardReadIteratorState) {
UNIT_ASSERT_VALUES_EQUAL(state.Quota.Bytes, 131729);
UNIT_ASSERT(state.State == NDataShard::TReadIteratorState::EState::Executing);
}
};
}

Y_UNIT_TEST_SUITE(DataShardReadIteratorPageFaults) {
Y_UNIT_TEST(CancelPageFaultedReadThenDropTable) {
Expand Down Expand Up @@ -4755,4 +4755,70 @@ Y_UNIT_TEST_SUITE(DataShardReadIteratorConsistency) {

}

Y_UNIT_TEST_SUITE(DataShardReadIteratorLatency) {

Y_UNIT_TEST(ReadSplitLatency) {
TPortManager pm;
TServerSettings serverSettings(pm.GetPort(2134));
serverSettings.SetDomainName("Root")
.SetUseRealThreads(false);
TServer::TPtr server = new TServer(serverSettings);

auto& runtime = *server->GetRuntime();
auto sender = runtime.AllocateEdgeActor();

runtime.SetLogPriority(NKikimrServices::TX_DATASHARD, NLog::PRI_TRACE);

InitRoot(server, sender);

TDisableDataShardLogBatching disableDataShardLogBatching;

CreateShardedTable(server, sender, "/Root", "table-1", 1);

// Insert initial data
ExecSQL(server, sender, "UPSERT INTO `/Root/table-1` (key, value) VALUES (1, 10), (2, 20), (3, 30), (4, 40), (5, 50);");
ExecSQL(server, sender, "UPSERT INTO `/Root/table-1` (key, value) VALUES (6, 60), (7, 70), (8, 80), (9, 90), (10, 100);");

// Copy table (this will ensure original shards stay alive after split)
{
auto senderCopy = runtime.AllocateEdgeActor();
ui64 txId = AsyncCreateCopyTable(server, senderCopy, "/Root", "table-2", "/Root/table-1");
WaitTxNotification(server, senderCopy, txId);
}

TBlockEvents<TEvDataShard::TEvRead> blockedReads(runtime);

Cerr << "... starting read from table-1" << Endl;
TString readSessionId;
auto readFuture = KqpSimpleBeginSend(runtime, readSessionId, R"(
SELECT * FROM `/Root/table-1` ORDER BY key;
)");

runtime.WaitFor("blocked TEvRead", [&]{ return blockedReads.size() >= 1; });

{
Cerr << "... splitting table-1" << Endl;
SetSplitMergePartCountLimit(server->GetRuntime(), -1);
auto shards1before = GetTableShards(server, sender, "/Root/table-1");
ui64 txId = AsyncSplitTable(server, sender, "/Root/table-1", shards1before.at(0), 5);
Cerr << "... split txId# " << txId << " started" << Endl;
WaitTxNotification(server, sender, txId);
Cerr << "... split txId# " << txId << " finished" << Endl;
}

runtime.SimulateSleep(TDuration::MilliSeconds(1));

auto readStartTs = runtime.GetCurrentTime();
blockedReads.Unblock();
blockedReads.Stop();
auto readResponse = runtime.WaitFuture(std::move(readFuture));
UNIT_ASSERT_VALUES_EQUAL(readResponse.operation().status(), Ydb::StatusIds::SUCCESS);
auto readLatency = runtime.GetCurrentTime() - readStartTs;
Cerr << "... read latency was " << readLatency << Endl;
UNIT_ASSERT_C(readLatency < TDuration::MilliSeconds(100),
"unexpected read latency " << readLatency);
}

}

} // namespace NKikimr
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