Fix resolved timestamp emitted too early for some displaced upserts (#8847)

Author: snaury

ydb/core/tx/datashard/cdc_stream_heartbeat.cpp

@@ -95,27 +95,27 @@ void TDataShard::EmitHeartbeats() {
         return;
     }
 
+    // We may possibly have more writes at this version
+    TRowVersion edge = GetMvccTxVersion(EMvccTxMode::ReadWrite);
+    bool wait = true;
+
     if (const auto& plan = TransQueue.GetPlan()) {
-        const auto version = Min(plan.begin()->ToRowVersion(), VolatileTxManager.GetMinUncertainVersion());
-        if (CdcStreamHeartbeatManager.ShouldEmitHeartbeat(version)) {
-            return Execute(new TTxCdcStreamEmitHeartbeats(this, version));
-        }
-        return;
+        edge = Min(edge, plan.begin()->ToRowVersion());
+        wait = false;
     }
 
     if (auto version = VolatileTxManager.GetMinUncertainVersion(); !version.IsMax()) {
-        if (CdcStreamHeartbeatManager.ShouldEmitHeartbeat(version)) {
-            return Execute(new TTxCdcStreamEmitHeartbeats(this, version));
-        }
-        return;
+        edge = Min(edge, version);
+        wait = false;
     }
 
-    const TRowVersion nextWrite = GetMvccTxVersion(EMvccTxMode::ReadWrite);
-    if (CdcStreamHeartbeatManager.ShouldEmitHeartbeat(nextWrite)) {
-        return Execute(new TTxCdcStreamEmitHeartbeats(this, nextWrite));
+    if (CdcStreamHeartbeatManager.ShouldEmitHeartbeat(edge)) {
+        return Execute(new TTxCdcStreamEmitHeartbeats(this, edge));
     }
 
-    WaitPlanStep(lowest.Next().Step);
+    if (wait) {
+        WaitPlanStep(lowest.Next().Step);
+    }
 }
 
 void TCdcStreamHeartbeatManager::Reset() {
@@ -215,7 +215,7 @@ bool TCdcStreamHeartbeatManager::ShouldEmitHeartbeat(const TRowVersion& edge) co
         return false;
     }
 
-    if (Schedule.top().Version > edge) {
+    if (Schedule.top().Version >= edge) {
         return false;
     }
 
@@ -225,7 +225,7 @@ bool TCdcStreamHeartbeatManager::ShouldEmitHeartbeat(const TRowVersion& edge) co
 THashMap<TPathId, TCdcStreamHeartbeatManager::THeartbeatInfo> TCdcStreamHeartbeatManager::EmitHeartbeats(
         NTable::TDatabase& db, const TRowVersion& edge)
 {
-    if (Schedule.empty() || Schedule.top().Version > edge) {
+    if (!ShouldEmitHeartbeat(edge)) {
         return {};
     }
 
@@ -234,7 +234,7 @@ THashMap<TPathId, TCdcStreamHeartbeatManager::THeartbeatInfo> TCdcStreamHeartbea
 
     while (true) {
         const auto& top = Schedule.top();
-        if (top.Version > edge) {
+        if (top.Version >= edge) {
             break;
         }
 

ydb/core/tx/datashard/datashard_ut_change_exchange.cpp

@@ -6,6 +6,7 @@
 #include <ydb/core/persqueue/events/global.h>
 #include <ydb/core/persqueue/user_info.h>
 #include <ydb/core/persqueue/write_meta.h>
+#include <ydb/core/testlib/actors/block_events.h>
 #include <ydb/core/tx/scheme_board/events.h>
 #include <ydb/core/tx/scheme_board/events_internal.h>
 #include <ydb/public/sdk/cpp/client/ydb_datastreams/datastreams.h>
@@ -2065,7 +2066,7 @@ Y_UNIT_TEST_SUITE(Cdc) {
         return result;
     }
 
-    void WaitForContent(TServer::TPtr server, const TActorId& sender, const TString& path, const TVector<TString>& expected) {
+    TVector<NJson::TJsonValue> WaitForContent(TServer::TPtr server, const TActorId& sender, const TString& path, const TVector<TString>& expected) {
         while (true) {
             const auto records = GetRecords(*server->GetRuntime(), sender, path, 0);
             for (ui32 i = 0; i < std::min(records.size(), expected.size()); ++i) {
@@ -2075,7 +2076,12 @@ Y_UNIT_TEST_SUITE(Cdc) {
             if (records.size() >= expected.size()) {
                 UNIT_ASSERT_VALUES_EQUAL_C(records.size(), expected.size(),
                     "Unexpected record: " << records.at(expected.size()).second);
-                break;
+                TVector<NJson::TJsonValue> values;
+                for (const auto& pr : records) {
+                    bool ok = NJson::ReadJsonTree(pr.second, &values.emplace_back());
+                    Y_ABORT_UNLESS(ok);
+                }
+                return values;
             }
 
             SimulateSleep(server, TDuration::Seconds(1));
@@ -3779,6 +3785,141 @@ Y_UNIT_TEST_SUITE(Cdc) {
         });
     }
 
+    Y_UNIT_TEST(ResolvedTimestampForDisplacedUpsert) {
+        TPortManager portManager;
+        TServer::TPtr server = new TServer(TServerSettings(portManager.GetPort(2134), {}, DefaultPQConfig())
+            .SetUseRealThreads(false)
+            .SetDomainName("Root")
+        );
+
+        TDisableDataShardLogBatching disableDataShardLogBatching;
+
+        auto& runtime = *server->GetRuntime();
+        const auto edgeActor = runtime.AllocateEdgeActor();
+
+        SetupLogging(runtime);
+        InitRoot(server, edgeActor);
+        SetSplitMergePartCountLimit(&runtime, -1);
+        CreateShardedTable(server, edgeActor, "/Root", "Table", SimpleTable());
+
+        WaitTxNotification(server, edgeActor, AsyncAlterAddStream(server, "/Root", "Table",
+            WithVirtualTimestamps(WithResolvedTimestamps(
+                TDuration::Seconds(3), Updates(NKikimrSchemeOp::ECdcStreamFormatJson)))));
+
+        Cerr << "... prepare" << Endl;
+        WaitForContent(server, edgeActor, "/Root/Table/Stream", {
+            R"({"resolved":"***"})",
+        });
+
+        KqpSimpleExec(runtime, R"(
+            UPSERT INTO `/Root/Table` (key, value) VALUES (1, 10);
+            )");
+
+        auto records = WaitForContent(server, edgeActor, "/Root/Table/Stream", {
+            R"({"resolved":"***"})",
+            R"({"update":{"value":10},"key":[1],"ts":"***"})",
+            R"({"resolved":"***"})",
+        });
+
+        // Take the final step
+        ui64 lastStep = records.back()["resolved"][0].GetUInteger();
+        Cerr << "... last heartbeat at " << lastStep << Endl;
+
+        const auto tableId = ResolveTableId(server, edgeActor, "/Root/Table");
+        const auto shards = GetTableShards(server, edgeActor, "/Root/Table");
+        UNIT_ASSERT_VALUES_EQUAL(shards.size(), 1u);
+
+        ui64 coordinator = ChangeStateStorage(Coordinator, server->GetSettings().Domain);
+        ui64 snapshotStep = lastStep + 3000 - 1;
+        ForwardToTablet(runtime, coordinator, edgeActor, new TEvTxProxy::TEvRequirePlanSteps(coordinator, snapshotStep));
+
+        TBlockEvents<TEvMediatorTimecast::TEvGranularUpdate> blockedGranularUpdates(runtime,
+            [&](auto& ev) {
+                return ev->Get()->Record.GetLatestStep() > snapshotStep;
+            });
+        TBlockEvents<TEvMediatorTimecast::TEvUpdate> blockedUpdates(runtime,
+            [&](auto& ev) {
+                return ev->Get()->Record.GetTimeBarrier() > snapshotStep;
+            });
+
+        Cerr << "... performing a read from snapshot just before the next heartbeat" << Endl;
+        {
+            auto req = std::make_unique<TEvDataShard::TEvRead>();
+            {
+                auto& record = req->Record;
+                record.SetReadId(1);
+                record.MutableTableId()->SetOwnerId(tableId.PathId.OwnerId);
+                record.MutableTableId()->SetTableId(tableId.PathId.LocalPathId);
+                record.AddColumns(1);
+                record.AddColumns(2);
+                record.SetResultFormat(NKikimrDataEvents::FORMAT_CELLVEC);
+                ui32 key = 1;
+                TVector<TCell> keys;
+                keys.push_back(TCell::Make(key));
+                req->Keys.push_back(TSerializedCellVec(TSerializedCellVec::Serialize(keys)));
+                record.MutableSnapshot()->SetStep(snapshotStep);
+                record.MutableSnapshot()->SetTxId(Max<ui64>());
+            }
+            ForwardToTablet(runtime, shards.at(0), edgeActor, req.release());
+            auto ev = runtime.GrabEdgeEventRethrow<TEvDataShard::TEvReadResult>(edgeActor);
+            auto* res = ev->Get();
+            UNIT_ASSERT_VALUES_EQUAL(res->Record.GetStatus().GetCode(), Ydb::StatusIds::SUCCESS);
+            UNIT_ASSERT_VALUES_EQUAL(res->Record.GetFinished(), true);
+            Cerr << "... read finished" << Endl;
+        }
+        for (int i = 0; i < 10; ++i) {
+            runtime.SimulateSleep(TDuration::MilliSeconds(1));
+        }
+
+        Cerr << "... starting upsert 1 (expected to displace)" << Endl;
+        auto upsert1 = KqpSimpleSend(runtime, R"(
+            UPSERT INTO `/Root/Table` (key, value) VALUES (2, 20);
+            )");
+        for (int i = 0; i < 10; ++i) {
+            runtime.SimulateSleep(TDuration::MilliSeconds(1));
+        }
+
+        Cerr << "... starting upsert 2 (expected to displace)" << Endl;
+        auto upsert2 = KqpSimpleSend(runtime, R"(
+            UPSERT INTO `/Root/Table` (key, value) VALUES (3, 30);
+            )");
+        for (int i = 0; i < 10; ++i) {
+            runtime.SimulateSleep(TDuration::MilliSeconds(1));
+        }
+
+        Cerr << "... unblocking updates" << Endl;
+        blockedGranularUpdates.Unblock().Stop();
+        blockedUpdates.Unblock().Stop();
+        for (int i = 0; i < 10; ++i) {
+            runtime.SimulateSleep(TDuration::MilliSeconds(1));
+        }
+
+        Cerr << "... checking the update is logged before the new resolved timestamp" << Endl;
+        records = WaitForContent(server, edgeActor, "/Root/Table/Stream", {
+            R"({"resolved":"***"})",
+            R"({"update":{"value":10},"key":[1],"ts":"***"})",
+            R"({"resolved":"***"})",
+            R"({"update":{"value":20},"key":[2],"ts":"***"})",
+            R"({"update":{"value":30},"key":[3],"ts":"***"})",
+            R"({"resolved":"***"})",
+        });
+
+        TRowVersion resolved(0, 0);
+        for (auto& record : records) {
+            if (record.Has("resolved")) {
+                resolved.Step = record["resolved"][0].GetUInteger();
+                resolved.TxId = record["resolved"][1].GetUInteger();
+            }
+            if (record.Has("ts")) {
+                TRowVersion ts(
+                    record["ts"][0].GetUInteger(),
+                    record["ts"][1].GetUInteger());
+                UNIT_ASSERT_C(resolved < ts,
+                    "Record with ts " << ts << " after resolved " << resolved);
+            }
+        }
+    }
+
 } // Cdc
 
 } // NKikimr