don't remove DESC sorting for sys view reads

Author: gridnevvvit

ydb/core/kqp/opt/physical/kqp_opt_phy_sort.cpp

@@ -93,6 +93,13 @@ TExprBase KqpRemoveRedundantSortOverReadTable(TExprBase node, TExprContext& ctx,
     }
 
     if (direction == ESortDirection::Reverse) {
+        // For sys views, we need to set reverse flag even if UseSource returns false
+        // because sys view actors can handle reverse direction
+        bool isSysView = tableDesc.Metadata->Kind == EKikimrTableKind::SysView;
+        if (isSysView) {
+            return node;
+        }
+
         if (!UseSource(kqpCtx, tableDesc) && kqpCtx.IsScanQuery()) {
             return node;
         }
@@ -206,6 +213,13 @@ TExprBase KqpRemoveRedundantSortOverReadTableFSM(
     }
 
     if (isReversed) {
+        // For sys views, we need to set reverse flag even if UseSource returns false
+        // because sys view actors can handle reverse direction
+        bool isSysView = tableDesc.Metadata->Kind == EKikimrTableKind::SysView;
+        if (isSysView) {
+            return node;
+        }
+
         if (!UseSource(kqpCtx, tableDesc) && kqpCtx.IsScanQuery()) {
             return node;
         }

ydb/core/kqp/ut/sysview/kqp_sys_view_ut.cpp

@@ -612,6 +612,225 @@ order by SessionId;)", "%Y-%m-%d %H:%M:%S %Z", sessionsSet.front().GetId().data(
         UNIT_ASSERT_VALUES_EQUAL(nodeIds[4], offset);
     }
 
+    Y_UNIT_TEST(PartitionStatsOrderByDesc) {
+        // Test ORDER BY DESC for partition_stats sys view
+        TKikimrRunner kikimr;
+        auto client = kikimr.GetQueryClient();
+        auto session = client.GetSession().GetValueSync().GetSession();
+
+        const auto describeResult = kikimr.GetTestClient().Describe(
+            kikimr.GetTestServer().GetRuntime(), "/Root/EightShard");
+
+        auto result = session.ExecuteQuery(R"(--!syntax_v1
+            SELECT PathId, PartIdx, Path
+            FROM `/Root/.sys/partition_stats`
+            ORDER BY PathId DESC, PartIdx DESC
+        )", NYdb::NQuery::TTxControl::NoTx()).GetValueSync();
+
+        UNIT_ASSERT_C(result.IsSuccess(), result.GetIssues().ToString());
+
+        // Collect all results
+        TVector<std::pair<ui64, ui64>> pathIdPartIdx;
+        auto resultSet = result.GetResultSet(0);
+        NYdb::TResultSetParser parser(resultSet);
+        while (parser.TryNextRow()) {
+            auto pathId = parser.ColumnParser("PathId").GetOptionalUint64().value();
+            auto partIdx = parser.ColumnParser("PartIdx").GetOptionalUint64().value();
+            pathIdPartIdx.push_back({pathId, partIdx});
+        }
+
+        // Verify we got some results
+        UNIT_ASSERT_C(pathIdPartIdx.size() > 0, "Expected at least one partition");
+
+        // Verify results are in descending order by PathId, then PartIdx
+        for (size_t i = 1; i < pathIdPartIdx.size(); ++i) {
+            const auto& prev = pathIdPartIdx[i - 1];
+            const auto& curr = pathIdPartIdx[i];
+
+            bool isOrdered = (prev.first > curr.first) ||
+                            (prev.first == curr.first && prev.second >= curr.second);
+
+            UNIT_ASSERT_C(isOrdered,
+                TStringBuilder() << "Results not in descending order: "
+                << "pathIdPartIdx[" << (i - 1) << "] = (" << prev.first << ", " << prev.second << ")"
+                << " > pathIdPartIdx[" << i << "] = (" << curr.first << ", " << curr.second << ")"
+                << ". ORDER BY DESC is being ignored by sys view actors.");
+        }
+    }
+
+    Y_UNIT_TEST(QuerySessionsOrderByDesc) {
+        // Test ORDER BY DESC for query_sessions sys view
+        NKikimrConfig::TFeatureFlags featureFlags;
+        featureFlags.SetEnableRealSystemViewPaths(true);
+        TKikimrSettings settings;
+        settings.SetWithSampleTables(false);
+        settings.SetFeatureFlags(featureFlags);
+        settings.SetAuthToken("root@builtin");
+        TKikimrRunner kikimr(settings);
+
+        auto client = kikimr.GetQueryClient();
+        auto session = client.GetSession().GetValueSync().GetSession();
+
+        // Create some sessions to have data
+        const size_t sessionsCount = 5;
+        std::vector<NYdb::NQuery::TSession> sessionsSet;
+        for(ui32 i = 0; i < sessionsCount; i++) {
+            sessionsSet.emplace_back(std::move(client.GetSession().GetValueSync().GetSession()));
+        }
+
+        // Wait a bit for sessions to be registered
+        ::Sleep(TDuration::MilliSeconds(100));
+
+        auto result = session.ExecuteQuery(R"(--!syntax_v1
+            SELECT SessionId, State, NodeId
+            FROM `/Root/.sys/query_sessions`
+            ORDER BY SessionId DESC
+        )", NYdb::NQuery::TTxControl::NoTx()).GetValueSync();
+
+        UNIT_ASSERT_C(result.IsSuccess(), result.GetIssues().ToString());
+
+        // Collect all results
+        TVector<std::string> sessionIds;
+        auto resultSet = result.GetResultSet(0);
+        NYdb::TResultSetParser parser(resultSet);
+        while (parser.TryNextRow()) {
+            auto sessionId = parser.ColumnParser("SessionId").GetOptionalUtf8().value();
+            sessionIds.push_back(sessionId);
+        }
+
+        // Verify we got some results
+        UNIT_ASSERT_C(sessionIds.size() > 0, "Expected at least one session");
+
+        // Verify results are in descending order (lexicographically)
+        for (size_t i = 1; i < sessionIds.size(); ++i) {
+            UNIT_ASSERT_C(sessionIds[i - 1] >= sessionIds[i],
+                TStringBuilder() << "Results not in descending order: "
+                << "sessionIds[" << (i - 1) << "] = \"" << sessionIds[i - 1] << "\""
+                << " < sessionIds[" << i << "] = \"" << sessionIds[i] << "\""
+                << ". ORDER BY DESC is being ignored by sys view actors.");
+        }
+    }
+
+    Y_UNIT_TEST(CompileCacheQueriesOrderByDesc) {
+        // Test ORDER BY DESC for compile_cache_queries sys view
+        auto serverSettings = TKikimrSettings().SetKqpSettings({ NKikimrKqp::TKqpSetting() });
+        serverSettings.AppConfig.MutableTableServiceConfig()->SetEnableImplicitQueryParameterTypes(true);
+        TKikimrRunner kikimr(serverSettings);
+        kikimr.GetTestServer().GetRuntime()->GetAppData().FeatureFlags.SetEnableCompileCacheView(true);
+        auto client = kikimr.GetQueryClient();
+        auto session = client.GetSession().GetValueSync().GetSession();
+
+        // Execute some queries to populate compile cache
+        auto tableClient = kikimr.GetTableClient();
+        for (ui32 i = 0; i < 3; ++i) {
+            auto tableSession = tableClient.CreateSession().GetValueSync().GetSession();
+            auto paramsBuilder = TParamsBuilder();
+            paramsBuilder.AddParam("$k").Uint64(i).Build();
+            auto executedResult = tableSession.ExecuteDataQuery(
+                R"(DECLARE $k AS Uint64;
+                SELECT COUNT(*) FROM `/Root/EightShard` WHERE Key = $k;)",
+                TTxControl::BeginTx().CommitTx(),
+                paramsBuilder.Build()
+            ).GetValueSync();
+            UNIT_ASSERT_C(executedResult.IsSuccess(), executedResult.GetIssues().ToString());
+        }
+
+        // Wait a bit for compile cache to be updated
+        ::Sleep(TDuration::MilliSeconds(100));
+
+        auto result = session.ExecuteQuery(R"(--!syntax_v1
+            SELECT QueryText, CompilationDuration
+            FROM `/Root/.sys/compile_cache_queries`
+            ORDER BY QueryText DESC
+        )", NYdb::NQuery::TTxControl::NoTx()).GetValueSync();
+
+        UNIT_ASSERT_C(result.IsSuccess(), result.GetIssues().ToString());
+
+        // Collect all results
+        TVector<std::string> queryTexts;
+        auto resultSet = result.GetResultSet(0);
+        NYdb::TResultSetParser parser(resultSet);
+        while (parser.TryNextRow()) {
+            auto queryText = parser.ColumnParser("QueryText").GetOptionalUtf8().value();
+            queryTexts.push_back(queryText);
+        }
+
+        // Verify we got some results
+        if (queryTexts.size() > 0) {
+            // Verify results are in descending order (lexicographically)
+            for (size_t i = 1; i < queryTexts.size(); ++i) {
+                UNIT_ASSERT_C(queryTexts[i - 1] >= queryTexts[i],
+                    TStringBuilder() << "Results not in descending order: "
+                    << "queryTexts[" << (i - 1) << "] = \"" << queryTexts[i - 1] << "\""
+                    << " < queryTexts[" << i << "] = \"" << queryTexts[i] << "\""
+                    << ". ORDER BY DESC is being ignored by sys view actors.");
+            }
+        }
+    }
+
+    Y_UNIT_TEST(TopQueriesOrderByDesc) {
+        // Test ORDER BY DESC for top_queries sys views
+        TKikimrRunner kikimr("", KikimrDefaultUtDomainRoot, 3);
+        auto client = kikimr.GetQueryClient();
+        auto session = client.GetSession().GetValueSync().GetSession();
+
+        // Execute some queries to populate stats
+        auto tableClient = kikimr.GetTableClient();
+        auto tableSession = tableClient.CreateSession().GetValueSync().GetSession();
+        {
+            auto result = tableSession.ExecuteDataQuery(Q_(R"(
+                SELECT * FROM `/Root/TwoShard`
+            )"), TTxControl::BeginTx().CommitTx()).GetValueSync();
+            UNIT_ASSERT_VALUES_EQUAL(result.GetStatus(), EStatus::SUCCESS);
+        }
+        {
+            auto result = tableSession.ExecuteDataQuery(Q_(R"(
+                SELECT * FROM `/Root/EightShard`
+            )"), TTxControl::BeginTx().CommitTx()).GetValueSync();
+            UNIT_ASSERT_VALUES_EQUAL(result.GetStatus(), EStatus::SUCCESS);
+        }
+
+        // Wait a bit for stats to be collected
+        ::Sleep(TDuration::MilliSeconds(500));
+
+        // Test top_queries_by_read_bytes_one_minute
+        auto result = session.ExecuteQuery(R"(--!syntax_v1
+            SELECT IntervalEnd, Rank, ReadBytes
+            FROM `/Root/.sys/top_queries_by_read_bytes_one_minute`
+            ORDER BY IntervalEnd DESC, Rank DESC
+        )", NYdb::NQuery::TTxControl::NoTx()).GetValueSync();
+
+        UNIT_ASSERT_C(result.IsSuccess(), result.GetIssues().ToString());
+
+        // Collect all results
+        TVector<std::pair<TInstant, ui32>> intervalEndRank;
+        auto resultSet = result.GetResultSet(0);
+        NYdb::TResultSetParser parser(resultSet);
+        while (parser.TryNextRow()) {
+            auto intervalEnd = parser.ColumnParser("IntervalEnd").GetOptionalTimestamp().value();
+            auto rank = parser.ColumnParser("Rank").GetOptionalUint32().value();
+            intervalEndRank.push_back({intervalEnd, rank});
+        }
+
+        // Verify we got some results (may be empty if no stats collected yet)
+        if (intervalEndRank.size() > 0) {
+            // Verify results are in descending order by IntervalEnd, then Rank
+            for (size_t i = 1; i < intervalEndRank.size(); ++i) {
+                const auto& prev = intervalEndRank[i - 1];
+                const auto& curr = intervalEndRank[i];
+
+                bool isOrdered = (prev.first > curr.first) ||
+                                (prev.first == curr.first && prev.second >= curr.second);
+
+                UNIT_ASSERT_C(isOrdered,
+                    TStringBuilder() << "Results not in descending order: "
+                    << "intervalEndRank[" << (i - 1) << "] = (" << prev.first.ToString() << ", " << prev.second << ")"
+                    << " > intervalEndRank[" << i << "] = (" << curr.first.ToString() << ", " << curr.second << ")"
+                    << ". ORDER BY DESC is being ignored by sys view actors.");
+            }
+        }
+    }
+
     Y_UNIT_TEST(QueryStatsSimple) {
         auto checkTable = [&] (const TStringBuf tableName) {
             TKikimrRunner kikimr("", KikimrDefaultUtDomainRoot, 3);