KIKIMR-19957 Implement UNIFORM_PARTITIONS for UUID.

Note that UUID is stored and compared as byte array with following byte
order:
```
UUID        00 11 22 33-44 55-66 77-88 99-AA BB CC DD EE FF
bytes       33 22 11 00 55 44 77 66 88 99 AA BB CC DD EE FF
byte order  3  2  1  0  5  4  7  6  8  9  10 11 12 13 14 15
```
Thus UUID ordering gives surprising results (not that anyone should
use it on UUIDs).

13 files changed, 258 insertions, 46 deletions

diff --git a/ydb/core/engine/mkql_proto.cpp b/ydb/core/engine/mkql_proto.cpp
index e14042352b..0a3867d876 100644
--- a/ydb/core/engine/mkql_proto.cpp
+++ b/ydb/core/engine/mkql_proto.cpp
@@ -18,7 +18,8 @@ bool CellsFromTuple(const NKikimrMiniKQL::TType* tupleType,
                     const TConstArrayRef<NScheme::TTypeInfo>& types,
                     bool allowCastFromString,
                     TVector<TCell>& key,
-                    TString& errStr)
+                    TString& errStr,
+                    TVector<TString>& memoryOwner)
 {
 
 #define CHECK_OR_RETURN_ERROR(cond, descr) \
@@ -157,18 +158,37 @@ bool CellsFromTuple(const NKikimrMiniKQL::TType* tupleType,
             if (v.HasBytes()) {
                 c = TCell(v.GetBytes().data(), v.GetBytes().size());
             } else if (v.HasText()) {
-                auto typeDesc = types[i].GetTypeDesc();            
+                auto typeDesc = types[i].GetTypeDesc();
                 auto convert = NPg::PgNativeBinaryFromNativeText(v.GetText(), NPg::PgTypeIdFromTypeDesc(typeDesc));
                 if (convert.Error) {
                     CHECK_OR_RETURN_ERROR(false, Sprintf("Cannot parse value of type Pg: %s in tuple at position %" PRIu32, convert.Error->data(), i));
                 } else {
-                    c = TCell(convert.Str.data(), convert.Str.size());
+                    auto &data = memoryOwner.emplace_back(convert.Str);
+                    c = TCell(data);
                 }
             } else {
                 CHECK_OR_RETURN_ERROR(false, Sprintf("Cannot parse value of type Pg in tuple at position %" PRIu32, i));
             }
             break;
         }
+        case NScheme::NTypeIds::Uuid:
+        {
+            if (v.HasLow128()) {
+                if (!v.HasHi128()) {
+                    CHECK_OR_RETURN_ERROR(false, Sprintf("UUID has Low128 but not Hi128 at position: %" PRIu32, i));
+                }
+                auto &data = memoryOwner.emplace_back();
+                data.resize(NUuid::UUID_LEN);
+                NUuid::UuidHalfsToBytes(data.Detach(), data.size(), v.GetHi128(), v.GetLow128());
+                c = TCell(data);
+            } else if (v.HasBytes()) {
+                Y_ABORT_UNLESS(v.GetBytes().size() == NUuid::UUID_LEN);
+                c = TCell(v.GetBytes().data(), v.GetBytes().size());
+            } else {
+                CHECK_OR_RETURN_ERROR(false, Sprintf("Cannot parse value of type Uuid in tuple at position %" PRIu32, i));
+            }
+            break;
+        }
         default:
             CHECK_OR_RETURN_ERROR(false, Sprintf("Unsupported typeId %" PRIu16 " at index %" PRIu32, typeId, i));
             break;
@@ -280,6 +300,14 @@ bool CellToValue(NScheme::TTypeInfo type, const TCell& c, NKikimrMiniKQL::TValue
         break;
     }
 
+    case NScheme::NTypeIds::Uuid: {
+        ui64 high = 0, low = 0;
+        NUuid::UuidBytesToHalfs(c.Data(), c.Size(), high, low);
+        val.MutableOptional()->SetHi128(high);
+        val.MutableOptional()->SetLow128(low);
+        break;
+    }
+
     default:
         errStr = "Unknown type: " + ToString(typeId);
         return false;
diff --git a/ydb/core/engine/mkql_proto.h b/ydb/core/engine/mkql_proto.h
index 1c316119c5..6e78806227 100644
--- a/ydb/core/engine/mkql_proto.h
+++ b/ydb/core/engine/mkql_proto.h
@@ -18,7 +18,8 @@ bool CellsFromTuple(const NKikimrMiniKQL::TType* tupleType,
                     const TConstArrayRef<NScheme::TTypeInfo>& expectedTypes,
                     bool allowCastFromString,
                     TVector<TCell>& key,
-                    TString& errStr);
+                    TString& errStr,
+                    TVector<TString>& memoryOwner);
 
 bool CellToValue(NScheme::TTypeInfo type, const TCell& c, NKikimrMiniKQL::TValue& val, TString& errStr);
 
diff --git a/ydb/core/engine/mkql_proto_ut.cpp b/ydb/core/engine/mkql_proto_ut.cpp
index 4e6a76ee43..eda9583be7 100644
--- a/ydb/core/engine/mkql_proto_ut.cpp
+++ b/ydb/core/engine/mkql_proto_ut.cpp
@@ -509,8 +509,9 @@ Y_UNIT_TEST(TestExportVariantStructTypeYdb) {
         UNIT_ASSERT_C(parseOk, paramsProto);
 
         TVector<TCell> cells;
+        TVector<TString> memoryOwner;
         TString errStr;
-        bool res = CellsFromTuple(&params.GetType(), params.GetValue(), types, true, cells, errStr);
+        bool res = CellsFromTuple(&params.GetType(), params.GetValue(), types, true, cells, errStr, memoryOwner);
         UNIT_ASSERT_VALUES_EQUAL_C(res, errStr.empty(), paramsProto);
 
         return errStr;
diff --git a/ydb/core/kqp/ut/scheme/kqp_scheme_ut.cpp b/ydb/core/kqp/ut/scheme/kqp_scheme_ut.cpp
index 83946d31e3..cff91a5cac 100644
--- a/ydb/core/kqp/ut/scheme/kqp_scheme_ut.cpp
+++ b/ydb/core/kqp/ut/scheme/kqp_scheme_ut.cpp
@@ -9,6 +9,8 @@
 #include <ydb/core/testlib/cs_helper.h>
 #include <ydb/core/testlib/common_helper.h>
 #include <ydb/core/formats/arrow/serializer/full.h>
+#include <ydb/library/uuid/uuid.h>
+
 #include <library/cpp/threading/local_executor/local_executor.h>
 
 #include <util/generic/serialized_enum.h>
@@ -1083,7 +1085,7 @@ Y_UNIT_TEST_SUITE(KqpScheme) {
             UNIT_ASSERT_VALUES_EQUAL_C(result.GetStatus(), EStatus::SUCCESS, result.GetIssues().ToString());
 
             auto describeResult = session.DescribeTable("/Root/moved").GetValueSync();
-            UNIT_ASSERT_C(describeResult.IsSuccess(), result.GetIssues().ToString());
+            UNIT_ASSERT_C(describeResult.IsSuccess(), describeResult.GetIssues().ToString());
         }
 
         {
@@ -1096,7 +1098,7 @@ Y_UNIT_TEST_SUITE(KqpScheme) {
             UNIT_ASSERT_VALUES_EQUAL_C(result.GetStatus(), EStatus::SUCCESS, result.GetIssues().ToString());
 
             auto describeResult = session.DescribeTable("/Root/table").GetValueSync();
-            UNIT_ASSERT_C(describeResult.IsSuccess(), result.GetIssues().ToString());
+            UNIT_ASSERT_C(describeResult.IsSuccess(), describeResult.GetIssues().ToString());
         }
 
         {
@@ -1124,11 +1126,11 @@ Y_UNIT_TEST_SUITE(KqpScheme) {
 
             {
                 auto describeResult = session.DescribeTable("/Root/moved").GetValueSync();
-                UNIT_ASSERT_C(describeResult.IsSuccess(), result.GetIssues().ToString());
+                UNIT_ASSERT_C(describeResult.IsSuccess(), describeResult.GetIssues().ToString());
             }
             {
                 auto describeResult = session.DescribeTable("/Root/movedsecond").GetValueSync();
-                UNIT_ASSERT_C(describeResult.IsSuccess(), result.GetIssues().ToString());
+                UNIT_ASSERT_C(describeResult.IsSuccess(), describeResult.GetIssues().ToString());
             }
         }
 
@@ -1165,12 +1167,12 @@ Y_UNIT_TEST_SUITE(KqpScheme) {
 
             {
                 auto describeResult = session.DescribeTable("/Root/second").GetValueSync();
-                UNIT_ASSERT_C(describeResult.IsSuccess(), result.GetIssues().ToString());
+                UNIT_ASSERT_C(describeResult.IsSuccess(), describeResult.GetIssues().ToString());
             }
 
             {
                 auto describeResult = session.DescribeTable("/Root/table").GetValueSync();
-                UNIT_ASSERT_C(!describeResult.IsSuccess(), result.GetIssues().ToString());
+                UNIT_ASSERT_C(!describeResult.IsSuccess(), describeResult.GetIssues().ToString());
             }
         }
 
@@ -1622,7 +1624,7 @@ Y_UNIT_TEST_SUITE(KqpScheme) {
 
         auto describeResult = session.DescribeTable(tableName,
             NYdb::NTable::TDescribeTableSettings().WithTableStatistics(true)).GetValueSync();
-        UNIT_ASSERT_C(describeResult.IsSuccess(), result.GetIssues().ToString());
+        UNIT_ASSERT_C(describeResult.IsSuccess(), describeResult.GetIssues().ToString());
         UNIT_ASSERT_VALUES_EQUAL(describeResult.GetTableDescription().GetPartitionsCount(), 4);
 
         AlterTableSetttings(session, tableName, {{"UNIFORM_PARTITIONS", "8"}}, compat,
@@ -1658,7 +1660,7 @@ Y_UNIT_TEST_SUITE(KqpScheme) {
 
         auto describeResult = session.DescribeTable(tableName,
             TDescribeTableSettings().WithTableStatistics(true).WithKeyShardBoundary(true)).GetValueSync();
-        UNIT_ASSERT_C(describeResult.IsSuccess(), result.GetIssues().ToString());
+        UNIT_ASSERT_C(describeResult.IsSuccess(), describeResult.GetIssues().ToString());
         UNIT_ASSERT_VALUES_EQUAL(describeResult.GetTableDescription().GetPartitionsCount(), 5);
 
         auto extractValue = [](const TValue& val) {
@@ -1724,7 +1726,7 @@ Y_UNIT_TEST_SUITE(KqpScheme) {
 
         auto describeResult = session.DescribeTable(tableName,
             TDescribeTableSettings().WithTableStatistics(true).WithKeyShardBoundary(true)).GetValueSync();
-        UNIT_ASSERT_C(describeResult.IsSuccess(), result.GetIssues().ToString());
+        UNIT_ASSERT_C(describeResult.IsSuccess(), describeResult.GetIssues().ToString());
         UNIT_ASSERT_VALUES_EQUAL(describeResult.GetTableDescription().GetPartitionsCount(), 4);
 
         auto extractValue = [](const TValue& val) {
@@ -1779,7 +1781,7 @@ Y_UNIT_TEST_SUITE(KqpScheme) {
 
         auto describeResult = session.DescribeTable(tableName,
             TDescribeTableSettings().WithTableStatistics(true).WithKeyShardBoundary(true)).GetValueSync();
-        UNIT_ASSERT_C(describeResult.IsSuccess(), result.GetIssues().ToString());
+        UNIT_ASSERT_C(describeResult.IsSuccess(), describeResult.GetIssues().ToString());
         UNIT_ASSERT_VALUES_EQUAL(describeResult.GetTableDescription().GetPartitionsCount(), 4);
 
         auto extractValue = [](const TValue& val) {
@@ -1854,6 +1856,141 @@ Y_UNIT_TEST_SUITE(KqpScheme) {
             "Partition at keys has 2 key values while there are only 1 key columns", "Unexpected error message");
     }
 
+    struct testData {
+        TString condition;
+        ui64 resultRows;
+        ui64 touchedPartitions;
+    };
+
+    void uuidInsertAndCheck(TSession &session, TString tableName, TVector<testData> expectedPartitions) {
+        TVector<TString> uuids {
+                {"AAAAAA00-0000-458F-ABE9-4A0CD520903B"},
+                {"AAAAAA11-0000-458F-ABE9-4A0CD520903B"},
+                {"AAAAAA22-0000-458F-ABE9-4A0CD520903B"},
+                {"AAAAAA33-0000-458F-ABE9-4A0CD520903B"},
+                {"AAAAAA44-0000-458F-ABE9-4A0CD520903B"},
+                {"AAAAAA55-0000-458F-ABE9-4A0CD520903B"},
+                {"AAAAAA66-0000-458F-ABE9-4A0CD520903B"},
+                {"AAAAAA77-0000-458F-ABE9-4A0CD520903B"},
+                {"AAAAAA88-0000-458F-ABE9-4A0CD520903B"},
+                {"AAAAAA99-0000-458F-ABE9-4A0CD520903B"},
+                {"AAAAAAAA-0000-458F-ABE9-4A0CD520903B"},
+                {"AAAAAABB-0000-458F-ABE9-4A0CD520903B"},
+                {"AAAAAACC-0000-458F-ABE9-4A0CD520903B"},
+                {"AAAAAADD-0000-458F-ABE9-4A0CD520903B"},
+                {"AAAAAAEE-0000-458F-ABE9-4A0CD520903B"},
+                {"AAAAAAFF-0000-458F-ABE9-4A0CD520903B"},
+        };
+        {
+            TStringBuilder builder;
+            builder << "REPLACE INTO `" << tableName << "` (Key, Value) VALUES ";
+            for (ui32 i = 0; i < uuids.size() - 1; ++i) {
+                builder << "(Uuid(\"" << uuids[i] << "\"), " << i << "),";
+            }
+            builder << "(Uuid(\"" << uuids[uuids.size() - 1] << "\"), " << uuids.size() - 1 << ");";
+            TString query = builder;
+
+            auto replaceResult = session.ExecuteDataQuery(query,
+                                                          TTxControl::BeginTx(TTxSettings::SerializableRW()).CommitTx()).GetValueSync();
+            UNIT_ASSERT_VALUES_EQUAL_C(replaceResult.GetStatus(), EStatus::SUCCESS,
+                                       replaceResult.GetIssues().ToString());
+        }
+
+        for (auto &test: expectedPartitions) {
+            TString query = Sprintf("SELECT Key as cnt from `%s` WHERE %s;", tableName.data(), test.condition.data());
+
+            NYdb::NTable::TExecDataQuerySettings execSettings;
+            execSettings.CollectQueryStats(ECollectQueryStatsMode::Profile);
+
+            auto selectResult = session.ExecuteDataQuery(query,
+                                                         TTxControl::BeginTx(TTxSettings::SerializableRW()).CommitTx(),
+                                                         execSettings).GetValueSync();
+            UNIT_ASSERT_VALUES_EQUAL_C(selectResult.GetStatus(), EStatus::SUCCESS,
+                                       selectResult.GetIssues().ToString());
+
+            UNIT_ASSERT_VALUES_EQUAL(selectResult.GetResultSets().size(), 1);
+
+            auto& stats = NYdb::TProtoAccessor::GetProto(*selectResult.GetStats());
+            UNIT_ASSERT_VALUES_EQUAL(selectResult.GetResultSet(0).RowsCount(), test.resultRows);
+            UNIT_ASSERT_VALUES_EQUAL(stats.query_phases(1).table_access(0).partitions_count(), test.touchedPartitions);
+        }
+    }
+
+    Y_UNIT_TEST(CreateTableWithPartitionAtKeysUuid) {
+        TKikimrSettings kikimrSettings;
+        TKikimrRunner kikimr(kikimrSettings);
+        auto db = kikimr.GetTableClient();
+        auto session = db.CreateSession().GetValueSync().GetSession();
+        TString tableName = "/Root/TableWithPartitionAtKeysSimpleUuid";
+
+        {
+            auto builder = TTableBuilder()
+                    .AddNonNullableColumn("Key", EPrimitiveType::Uuid)
+                    .AddNullableColumn("Value", EPrimitiveType::Int32)
+                    .SetPrimaryKeyColumn("Key");
+
+            // Ordering is not lexicographic as UUID is stored in binary form with the following byte order
+            // from original hex pairs: [3 2 1 0 5 4 7 6 8 9 a b c d e f]
+            // String UUID (with spaces added) 00 11 22 33-44 55-66 77-88 99-AA BB CC DD EE FF
+            // becomes                         33 22 11 00 55 44 77 66 88 99 AA BB CC DD EE FF
+            const TVector <TUuidValue> expectedRanges = {
+                    TUuidValue("FFFFFF11-C00F-458F-ABE9-4A0CD520903B"),
+                    TUuidValue("FFFFFFDD-AF48-428B-9D13-893C220118C4")
+            };
+            auto explicitPartitions = TExplicitPartitions();
+            for (ui32 i = 0; i < expectedRanges.size(); i++) {
+                explicitPartitions.AppendSplitPoints(
+                        TValueBuilder().BeginTuple().AddElement()
+                                .OptionalUuid(expectedRanges[i]).EndTuple().Build()
+                );
+            }
+            auto result = session.CreateTable(tableName,
+                                              builder.Build(),
+                                              TCreateTableSettings()
+                                                      .PartitioningPolicy(TPartitioningPolicy().ExplicitPartitions(explicitPartitions))
+            ).GetValueSync();
+            UNIT_ASSERT_VALUES_EQUAL_C(result.GetStatus(), EStatus::SUCCESS, result.GetIssues().ToString());
+        }
+        // See comment above for comparison explanation.
+        TVector<testData> inputs = {
+                {"Key > Cast(\"00000000-FFFF-FFFF-ABE9-4A0CD520903B\" as Uuid)",16, 3},
+                {"Key > Cast(\"FFFFFF11-C00F-458F-ABE9-4A0CD520903B\" as Uuid)", 14, 2},
+                {"Key < Cast(\"FFFFFF11-C00F-458F-ABE9-4A0CD520903B\" as Uuid)", 2, 1}
+        };
+        uuidInsertAndCheck(session, tableName, inputs);
+    }
+
+    Y_UNIT_TEST(CreateTableWithUniformPartitionsUuid) {
+        TKikimrSettings kikimrSettings;
+        TKikimrRunner kikimr(kikimrSettings);
+        auto db = kikimr.GetTableClient();
+        auto session = db.CreateSession().GetValueSync().GetSession();
+        TString tableName = "/Root/TableWithPartitionAtKeysSimpleUuid";
+
+        {
+            auto builder = TTableBuilder()
+                    .AddNonNullableColumn("Key", EPrimitiveType::Uuid)
+                    .AddNullableColumn("Value", EPrimitiveType::Int32)
+                    .SetPrimaryKeyColumn("Key");
+
+            auto result = session.CreateTable(tableName,
+                                              builder.Build(),
+                                              TCreateTableSettings()
+                                                  .PartitioningPolicy(TPartitioningPolicy().UniformPartitions(4))
+            ).GetValueSync();
+            UNIT_ASSERT_VALUES_EQUAL_C(result.GetStatus(), EStatus::SUCCESS, result.GetIssues().ToString());
+        }
+        // See comment above for comparison explanation.
+        TVector<testData> inputs = {
+                {"Key > Cast(\"00000000-FFFF-FFFF-ABE9-4A0CD520903B\" as Uuid)",16, 4},
+                {"Key < Cast(\"0000003F-C00F-458F-ABE9-4A0CD520903B\" as Uuid)", 4, 1},
+                {"Key < Cast(\"0000007F-C00F-458F-ABE9-4A0CD520903B\" as Uuid)", 8, 2},
+                {"Key < Cast(\"000000BF-C00F-458F-ABE9-4A0CD520903B\" as Uuid)", 12, 3},
+                {"Key < Cast(\"000000FF-C00F-458F-ABE9-4A0CD520903B\" as Uuid)", 15, 4}
+        };
+        uuidInsertAndCheck(session, tableName, inputs);
+    }
+
     Y_UNIT_TEST(CreateTableWithFamiliesRegular) {
         TKikimrRunner kikimr;
         auto db = kikimr.GetTableClient();
@@ -1876,7 +2013,7 @@ Y_UNIT_TEST_SUITE(KqpScheme) {
         UNIT_ASSERT_VALUES_EQUAL_C(result.GetStatus(), EStatus::SUCCESS, result.GetIssues().ToString());
 
         auto describeResult = session.DescribeTable(tableName, NYdb::NTable::TDescribeTableSettings()).GetValueSync();
-        UNIT_ASSERT_C(describeResult.IsSuccess(), result.GetIssues().ToString());
+        UNIT_ASSERT_C(describeResult.IsSuccess(), describeResult.GetIssues().ToString());
         const auto& columnFamilies = describeResult.GetTableDescription().GetColumnFamilies();
         UNIT_ASSERT_VALUES_EQUAL(columnFamilies.size(), 3);
         for (const auto& family : columnFamilies) {
@@ -1915,7 +2052,7 @@ Y_UNIT_TEST_SUITE(KqpScheme) {
 
         {
             auto describeResult = session.DescribeTable(tableName, NYdb::NTable::TDescribeTableSettings()).GetValueSync();
-            UNIT_ASSERT_C(describeResult.IsSuccess(), result.GetIssues().ToString());
+            UNIT_ASSERT_C(describeResult.IsSuccess(), describeResult.GetIssues().ToString());
             const auto& columnFamilies = describeResult.GetTableDescription().GetColumnFamilies();
             UNIT_ASSERT_VALUES_EQUAL(columnFamilies.size(), 2);
             for (const auto& family : columnFamilies) {
@@ -1947,7 +2084,7 @@ Y_UNIT_TEST_SUITE(KqpScheme) {
 
         {
             auto describeResult = session.DescribeTable(tableName, NYdb::NTable::TDescribeTableSettings()).GetValueSync();
-            UNIT_ASSERT_C(describeResult.IsSuccess(), result.GetIssues().ToString());
+            UNIT_ASSERT_C(describeResult.IsSuccess(), describeResult.GetIssues().ToString());
             const auto& columnFamilies = describeResult.GetTableDescription().GetColumnFamilies();
             UNIT_ASSERT_VALUES_EQUAL(columnFamilies.size(), 3);
             for (const auto& family : columnFamilies) {
@@ -1992,7 +2129,7 @@ Y_UNIT_TEST_SUITE(KqpScheme) {
         UNIT_ASSERT_VALUES_EQUAL_C(result.GetStatus(), EStatus::SUCCESS, result.GetIssues().ToString());
 
         auto describeResult = session.DescribeTable(tableName).GetValueSync();
-        UNIT_ASSERT_C(describeResult.IsSuccess(), result.GetIssues().ToString());
+        UNIT_ASSERT_C(describeResult.IsSuccess(), describeResult.GetIssues().ToString());
         UNIT_ASSERT(describeResult.GetTableDescription().GetStorageSettings().GetStoreExternalBlobs().GetOrElse(false));
     }
 
@@ -3189,7 +3326,7 @@ Y_UNIT_TEST_SUITE(KqpScheme) {
         UNIT_ASSERT_VALUES_EQUAL_C(result.GetStatus(), EStatus::SUCCESS, result.GetIssues().ToString());
 
         auto describeResult = session.DescribeTable(tableName, NYdb::NTable::TDescribeTableSettings()).GetValueSync();
-        UNIT_ASSERT_C(describeResult.IsSuccess(), result.GetIssues().ToString());
+        UNIT_ASSERT_C(describeResult.IsSuccess(), describeResult.GetIssues().ToString());
         const auto tableDesc = session.DescribeTable(tableName).GetValueSync().GetTableDescription();
         TVector<TTableColumn> columns = tableDesc.GetTableColumns();
         UNIT_ASSERT_VALUES_EQUAL(columns.size(), 3);
@@ -3831,7 +3968,7 @@ Y_UNIT_TEST_SUITE(KqpScheme) {
             auto result = session.ExecuteSchemeQuery(query).GetValueSync();
             UNIT_ASSERT_VALUES_EQUAL_C(result.GetStatus(), EStatus::SUCCESS,
                                        result.GetIssues().ToString());
-        }        
+        }
 
         {
             TString query = R"(
@@ -3898,7 +4035,7 @@ Y_UNIT_TEST_SUITE(KqpScheme) {
             auto result = session.ExecuteSchemeQuery(query).GetValueSync();
             UNIT_ASSERT_VALUES_EQUAL_C(result.GetStatus(), EStatus::SUCCESS,
                                        result.GetIssues().ToString());
-        }        
+        }
     }
 
     Y_UNIT_TEST(DefaultValuesForTable3) {
@@ -3923,7 +4060,7 @@ Y_UNIT_TEST_SUITE(KqpScheme) {
             UNIT_ASSERT_VALUES_EQUAL_C(result.GetStatus(), EStatus::GENERIC_ERROR, result.GetIssues().ToString());
             UNIT_ASSERT_STRING_CONTAINS(result.GetIssues().ToString(),
                                         "Default expr Key is nullable or optional, but column has not null constraint");
-        }        
+        }
     }
 
     Y_UNIT_TEST(DefaultValuesForTable4) {
@@ -3949,7 +4086,7 @@ Y_UNIT_TEST_SUITE(KqpScheme) {
             auto result = session.ExecuteSchemeQuery(query).GetValueSync();
             UNIT_ASSERT_VALUES_EQUAL_C(result.GetStatus(), EStatus::GENERIC_ERROR,
                                        result.GetIssues().ToString());
-        }        
+        }
     }
 
     Y_UNIT_TEST(ChangefeedRetentionPeriod) {
diff --git a/ydb/core/tx/schemeshard/schemeshard__operation_create_pq.cpp b/ydb/core/tx/schemeshard/schemeshard__operation_create_pq.cpp
index 63c23985c1..f22f6e8dbc 100644
--- a/ydb/core/tx/schemeshard/schemeshard__operation_create_pq.cpp
+++ b/ydb/core/tx/schemeshard/schemeshard__operation_create_pq.cpp
@@ -121,8 +121,9 @@ TTopicInfo::TPtr CreatePersQueueGroup(TOperationContext& context,
                 if (op.PartitionBoundariesSize()) {
                     TVector<TCell> cells;
                     TString error;
+                    TVector<TString> memoryOwner;
                     if (!NMiniKQL::CellsFromTuple(nullptr, op.GetPartitionBoundaries(i), pqGroupInfo->KeySchema, false,
-                                                  cells, error)) {
+                                                  cells, error, memoryOwner)) {
                         status = NKikimrScheme::StatusSchemeError;
                         errStr = Sprintf("Invalid partition boundary at position: %u, error: %s", i, error.data());
                         return nullptr;
diff --git a/ydb/core/tx/schemeshard/schemeshard_impl.cpp b/ydb/core/tx/schemeshard/schemeshard_impl.cpp
index 8d92948bcc..c4972c3533 100644
--- a/ydb/core/tx/schemeshard/schemeshard_impl.cpp
+++ b/ydb/core/tx/schemeshard/schemeshard_impl.cpp
@@ -14,6 +14,8 @@
 #include <ydb/core/statistics/stat_service.h>
 #include <ydb/core/scheme/scheme_types_proto.h>
 #include <ydb/library/yql/minikql/mkql_type_ops.h>
+#include <util/system/byteorder.h>
+#include <util/system/unaligned_mem.h>
 
 namespace NKikimr {
 namespace NSchemeShard {
@@ -6229,10 +6231,11 @@ bool TSchemeShard::FillSplitPartitioning(TVector<TString>& rangeEnds, const TCon
         auto& boundary = boundaries.Get(i);
         TVector<TCell> rangeEnd;
         TSerializedCellVec prefix;
+        TVector<TString> memoryOwner;
         if (boundary.HasSerializedKeyPrefix()) {
             prefix.Parse(boundary.GetSerializedKeyPrefix());
             rangeEnd = TVector<TCell>(prefix.GetCells().begin(), prefix.GetCells().end());
-        } else if (!NMiniKQL::CellsFromTuple(nullptr, boundary.GetKeyPrefix(), keyColTypes, false, rangeEnd, errStr)) {
+        } else if (!NMiniKQL::CellsFromTuple(nullptr, boundary.GetKeyPrefix(), keyColTypes, false, rangeEnd, errStr, memoryOwner)) {
             errStr = Sprintf("Error at split boundary %d: %s", i, errStr.data());
             return false;
         }
@@ -6405,6 +6408,22 @@ bool TSchemeShard::FillUniformPartitioning(TVector<TString>& rangeEnds, ui32 key
             maxVal = Max<ui64>();
             valSz = 8;
             break;
+        case NScheme::NTypeIds::Uuid: {
+            maxVal = Max<ui64>();
+            valSz = 16;
+            char buffer[16] = {};
+
+            for (ui32 i = 1; i < partitionCount; ++i) {
+                ui64 val = maxVal * (double(i) / partitionCount);
+                // Make sure most significant byte is at the start of the byte buffer for UUID comparison.
+                val = HostToInet(val);
+                WriteUnaligned<ui64>(buffer, val);
+                rangeEnd[0] = TCell(buffer, valSz);
+                rangeEnds.push_back(TSerializedCellVec::Serialize(rangeEnd));
+            }
+
+            return true;
+        }
         default:
             errStr = TStringBuilder() << "Unsupported first key column type " << NScheme::TypeName(firstKeyColType) << ", only Uint32 and Uint64 are supported";
             return false;
diff --git a/ydb/core/tx/schemeshard/ut_helpers/ls_checks.cpp b/ydb/core/tx/schemeshard/ut_helpers/ls_checks.cpp
index d0de3aa5e5..881813906a 100644
--- a/ydb/core/tx/schemeshard/ut_helpers/ls_checks.cpp
+++ b/ydb/core/tx/schemeshard/ut_helpers/ls_checks.cpp
@@ -484,7 +484,8 @@ void CheckBoundaries(const NKikimrScheme::TEvDescribeSchemeResult &record) {
     for (ui32 i = 0; i < descr.GetTable().SplitBoundarySize(); ++i) {
         const auto& b = descr.GetTable().GetSplitBoundary(i);
         TVector<TCell> cells;
-        NMiniKQL::CellsFromTuple(nullptr, b.GetKeyPrefix(), keyColTypes, false, cells, errStr);
+        TVector<TString> memoryOwner;
+        NMiniKQL::CellsFromTuple(nullptr, b.GetKeyPrefix(), keyColTypes, false, cells, errStr, memoryOwner);
         UNIT_ASSERT_VALUES_EQUAL(errStr, "");
 
         TString serialized = TSerializedCellVec::Serialize(cells);
diff --git a/ydb/core/tx/tx_proxy/datareq.cpp b/ydb/core/tx/tx_proxy/datareq.cpp
index c5b49e633c..cc4fc17df5 100644
--- a/ydb/core/tx/tx_proxy/datareq.cpp
+++ b/ydb/core/tx/tx_proxy/datareq.cpp
@@ -3024,6 +3024,7 @@ bool TDataReq::ParseRangeKey(const NKikimrMiniKQL::TParams &proto,
                              EParseRangeKeyExp exp)
 {
     TVector<TCell> key;
+    TVector<TString> memoryOwner;
     if (proto.HasValue()) {
         if (!proto.HasType()) {
             UnresolvedKeys.push_back("No type was specified in the range key tuple");
@@ -3033,7 +3034,7 @@ bool TDataReq::ParseRangeKey(const NKikimrMiniKQL::TParams &proto,
         auto& value = proto.GetValue();
         auto& type = proto.GetType();
         TString errStr;
-        bool res = NMiniKQL::CellsFromTuple(&type, value, keyType, true, key, errStr);
+        bool res = NMiniKQL::CellsFromTuple(&type, value, keyType, true, key, errStr, memoryOwner);
         if (!res) {
             UnresolvedKeys.push_back("Failed to parse range key tuple: " + errStr);
             return false;
diff --git a/ydb/core/tx/tx_proxy/read_table_impl.cpp b/ydb/core/tx/tx_proxy/read_table_impl.cpp
index 6645208e76..e5577d058a 100644
--- a/ydb/core/tx/tx_proxy/read_table_impl.cpp
+++ b/ydb/core/tx/tx_proxy/read_table_impl.cpp
@@ -96,6 +96,7 @@ namespace {
             TVector<TString>& unresolvedKeys)
     {
         TVector<TCell> key;
+        TVector<TString> memoryOwner;
         if (proto.HasValue()) {
             if (!proto.HasType()) {
                 unresolvedKeys.push_back("No type was specified in the range key tuple");
@@ -105,7 +106,7 @@ namespace {
             auto& value = proto.GetValue();
             auto& type = proto.GetType();
             TString errStr;
-            bool res = NMiniKQL::CellsFromTuple(&type, value, keyTypes, true, key, errStr);
+            bool res = NMiniKQL::CellsFromTuple(&type, value, keyTypes, true, key, errStr, memoryOwner);
             if (!res) {
                 unresolvedKeys.push_back("Failed to parse range key tuple: " + errStr);
                 return false;
diff --git a/ydb/core/tx/tx_proxy/resolvereq.cpp b/ydb/core/tx/tx_proxy/resolvereq.cpp
index 01353f98e1..eb916abc89 100644
--- a/ydb/core/tx/tx_proxy/resolvereq.cpp
+++ b/ydb/core/tx/tx_proxy/resolvereq.cpp
@@ -25,6 +25,7 @@ namespace {
             TVector<TString>& unresolvedKeys)
     {
         TVector<TCell> key;
+        TVector<TString> memoryOwner;
         if (proto.HasValue()) {
             if (!proto.HasType()) {
                 unresolvedKeys.push_back("No type was specified in the range key tuple");
@@ -34,7 +35,7 @@ namespace {
             auto& value = proto.GetValue();
             auto& type = proto.GetType();
             TString errStr;
-            bool res = NMiniKQL::CellsFromTuple(&type, value, keyTypes, true, key, errStr);
+            bool res = NMiniKQL::CellsFromTuple(&type, value, keyTypes, true, key, errStr, memoryOwner);
             if (!res) {
                 unresolvedKeys.push_back("Failed to parse range key tuple: " + errStr);
                 return false;
diff --git a/ydb/library/mkql_proto/mkql_proto.h b/ydb/library/mkql_proto/mkql_proto.h
index 52817eea90..e9ed92b320 100644
--- a/ydb/library/mkql_proto/mkql_proto.h
+++ b/ydb/library/mkql_proto/mkql_proto.h
@@ -4,6 +4,7 @@
 #include <ydb/library/yql/minikql/mkql_node.h>
 #include <ydb/library/mkql_proto/protos/minikql.pb.h>
 #include <ydb/public/api/protos/ydb_value.pb.h>
+#include <ydb/library/uuid/uuid.h>
 
 namespace NKikimr::NMiniKQL {
 
@@ -31,25 +32,19 @@ TRuntimeNode ImportValueFromProto(const NKikimrMiniKQL::TType& type, const NKiki
 TRuntimeNode ImportValueFromProto(const NKikimrMiniKQL::TParams& params, const TTypeEnvironment& env);
 
 inline void UuidToMkqlProto(const char* str, size_t sz, NKikimrMiniKQL::TValue& res) {
-    union {
-        ui64 half[2];
-        char bytes[sizeof(ui64) * 2];
-    } buf;
-    Y_ABORT_UNLESS(sizeof(buf) == sz);
-    memcpy(buf.bytes, str, sizeof(buf));
-    res.SetLow128(buf.half[0]);
-    res.SetHi128(buf.half[1]);
+    ui64 high = 0, low = 0;
+    NUuid::UuidBytesToHalfs(str, sz, high, low);
+
+    res.SetLow128(low);
+    res.SetHi128(high);
 }
 
 inline void UuidToYdbProto(const char* str, size_t sz, Ydb::Value& res) {
-    union {
-        ui64 half[2];
-        char bytes[sizeof(ui64) * 2];
-    } buf;
-    Y_ABORT_UNLESS(sizeof(buf) == sz);
-    memcpy(buf.bytes, str, sizeof(buf));
-    res.set_low_128(buf.half[0]);
-    res.set_high_128(buf.half[1]);
+    ui64 high = 0, low = 0;
+    NUuid::UuidBytesToHalfs(str, sz, high, low);
+
+    res.set_low_128(low);
+    res.set_high_128(high);
 }
 
 }
diff --git a/ydb/library/uuid/uuid.h b/ydb/library/uuid/uuid.h
index 4c89090371..b1bb1912bd 100644
--- a/ydb/library/uuid/uuid.h
+++ b/ydb/library/uuid/uuid.h
@@ -1,5 +1,6 @@
 #pragma once
 #include <util/system/types.h>
+#include <util/system/yassert.h>
 
 #include <cctype>
 #include <utility>
@@ -9,6 +10,8 @@ class IOutputStream;
 namespace NKikimr {
 namespace NUuid {
 
+static constexpr ui32 UUID_LEN = 16;
+
 void UuidToString(ui16 dw[8], IOutputStream& out);
 void UuidHalfsToByteString(ui64 low, ui64 hi, IOutputStream& out);
 
@@ -92,5 +95,27 @@ bool ParseUuidToArray(const T& buf, ui16* dw, bool shortForm) {
     return true;
 }
 
+inline void UuidHalfsToBytes(char *dst, size_t dstSize, ui64 hi, ui64 low) {
+    union {
+        char bytes[UUID_LEN];
+        ui64 half[2];
+    } buf;
+    Y_ABORT_UNLESS(UUID_LEN == dstSize);
+    buf.half[0] = low;
+    buf.half[1] = hi;
+    memcpy(dst, buf.bytes, sizeof(buf));
+}
+
+inline void UuidBytesToHalfs(const char *str, size_t sz, ui64 &high, ui64 &low) {
+    union {
+        char bytes[UUID_LEN];
+        ui64 half[2];
+    } buf;
+    Y_ABORT_UNLESS(UUID_LEN == sz);
+    memcpy(buf.bytes, str, sizeof(buf));
+    low = buf.half[0];
+    high = buf.half[1];
+}
+
 }
 }
diff --git a/ydb/public/sdk/cpp/client/ydb_value/value.cpp b/ydb/public/sdk/cpp/client/ydb_value/value.cpp
index ef7a6179b9..0b2e1e24c8 100644
--- a/ydb/public/sdk/cpp/client/ydb_value/value.cpp
+++ b/ydb/public/sdk/cpp/client/ydb_value/value.cpp
@@ -1021,6 +1021,7 @@ TUuidValue::TUuidValue(const TString& uuidString) {
         ThrowFatalError(TStringBuilder() << "Unable to parse string as uuid");
     }
     static_assert(sizeof(dw) == sizeof(Buf_.Bytes));
+    // TODO: check output on big-endian machines here and everywhere.
     std::memcpy(Buf_.Bytes, dw, sizeof(dw));
 }