KIKIMR-19521 BTreeIndex Test (#653)

6 files changed, 381 insertions, 42 deletions

diff --git a/ydb/core/tablet_flat/benchmark/b_charge.cpp b/ydb/core/tablet_flat/benchmark/b_charge.cpp
index ece5e52034..da1c06dbbd 100644
--- a/ydb/core/tablet_flat/benchmark/b_charge.cpp
+++ b/ydb/core/tablet_flat/benchmark/b_charge.cpp
@@ -32,35 +32,10 @@ namespace {
         ui64 TouchedCount = 0;
     };
 
-    struct TCooker {
-        TCooker(const TRowScheme &scheme)
-            : Tool(scheme)
-            , Writer(new TPartScheme(scheme.Cols), { }, NPage::TGroupId(0))
-        {
-
-        }
-
-        TCooker& Add(const NTest::TRow &row, ui64 offset, ui32 page)
-        {
-            const TCelled key(Tool.LookupKey(row), *Tool.Scheme.Keys, false);
-
-            return Writer.Add(key, offset, page), *this;
-        }
-
-        TSharedData Flush()
-        {
-            return Writer.Flush();
-        }
-
-    private:
-        const NTest::TRowTool Tool;
-        NPage::TIndexWriter Writer;
-    };
-
-    struct TModel : public benchmark::Fixture {
+    struct TPrechargeFixture : public benchmark::Fixture {
         using TGroupId = NPage::TGroupId;
 
-        TModel()
+        TPrechargeFixture()
             : Tool(*Mass.Model->Scheme)
         {
             Y_ABORT_UNLESS(NTest::IndexTools::CountMainPages(*Eggs.Lone()) > 120);
@@ -125,7 +100,7 @@ namespace {
     };
 }
 
-BENCHMARK_DEFINE_F(TModel, PrechargeByKeys)(benchmark::State& state) {
+BENCHMARK_DEFINE_F(TPrechargeFixture, PrechargeByKeys)(benchmark::State& state) {
     ui64 items = state.range(0);
 
     const auto &keyDefaults = *Tool.Scheme.Keys;
@@ -144,7 +119,7 @@ BENCHMARK_DEFINE_F(TModel, PrechargeByKeys)(benchmark::State& state) {
     state.counters["Touched"] = benchmark::Counter(Env->TouchedCount, benchmark::Counter::kAvgIterations);
 }
 
-BENCHMARK_DEFINE_F(TModel, PrechargeByRows)(benchmark::State& state) {
+BENCHMARK_DEFINE_F(TPrechargeFixture, PrechargeByRows)(benchmark::State& state) {
     ui64 items = state.range(0);
 
     const auto &keyDefaults = *Tool.Scheme.Keys;
@@ -160,12 +135,18 @@ BENCHMARK_DEFINE_F(TModel, PrechargeByRows)(benchmark::State& state) {
     state.counters["Touched"] = Env->TouchedCount / it;
 }
 
-BENCHMARK_REGISTER_F(TModel, PrechargeByKeys)
-    ->ArgsProduct({/*items:*/ {0, 100, 1000}, /*fail:*/{0, 1}, /*groups:*/ {0, 1, 2}})
+BENCHMARK_REGISTER_F(TPrechargeFixture, PrechargeByKeys)
+    ->ArgsProduct({
+        /* items: */ {0, 100, 1000}, 
+        /* fail: */ {0, 1}, 
+        /* groups: */ {0, 1, 2}})
     ->Unit(benchmark::kMicrosecond);
 
-BENCHMARK_REGISTER_F(TModel, PrechargeByRows)
-    ->ArgsProduct({/*items:*/ {0, 100, 1000}, /*fail:*/{0, 1}, /*groups:*/ {0, 1, 2}})
+BENCHMARK_REGISTER_F(TPrechargeFixture, PrechargeByRows)
+    ->ArgsProduct({
+        /* items: */ {0, 100, 1000}, 
+        /* fail: */{0, 1}, 
+        /* groups: */ {0, 1, 2}})
     ->Unit(benchmark::kMicrosecond);
 
 }
diff --git a/ydb/core/tablet_flat/benchmark/b_part_index.cpp b/ydb/core/tablet_flat/benchmark/b_part_index.cpp
new file mode 100644
index 0000000000..bdc8759091
--- /dev/null
+++ b/ydb/core/tablet_flat/benchmark/b_part_index.cpp
@@ -0,0 +1,249 @@
+#include <benchmark/benchmark.h>
+
+#include <ydb/core/tablet_flat/flat_row_celled.h>
+#include <ydb/core/tablet_flat/flat_part_charge_range.h>
+#include <ydb/core/tablet_flat/flat_part_charge_create.h>
+#include <ydb/core/tablet_flat/test/libs/rows/cook.h>
+#include <ydb/core/tablet_flat/test/libs/rows/tool.h>
+#include <ydb/core/tablet_flat/test/libs/table/model/large.h>
+#include <ydb/core/tablet_flat/test/libs/table/test_make.h>
+#include <ydb/core/tablet_flat/test/libs/table/test_mixer.h>
+#include "ydb/core/tablet_flat/flat_part_btree_index_iter.h"
+#include "ydb/core/tablet_flat/test/libs/table/wrap_iter.h"
+#include <ydb/core/tablet_flat/test/libs/table/test_writer.h>
+#include <ydb/core/tablet_flat/test/libs/table/test_envs.h>
+#include <ydb/core/tablet_flat/test/libs/table/wrap_part.h>
+#include <ydb/core/tablet_flat/test/libs/table/test_steps.h>
+
+namespace NKikimr {
+namespace NTable {
+
+namespace {
+    using namespace NTest;
+
+    using TCheckIt = TChecker<TWrapIter, TSubset>;
+    using TCheckReverseIt = TChecker<TWrapReverseIter, TSubset>;
+
+    NPage::TConf PageConf(size_t groups, bool writeBTreeIndex) noexcept
+    {
+        NPage::TConf conf{ true, 1024 };
+
+        conf.Groups.resize(groups);
+        for (size_t group : xrange(groups)) {
+            conf.Group(group).PageSize = 1024;
+            conf.Group(group).BTreeIndexNodeTargetSize = 1024;
+        }
+
+        conf.WriteBTreeIndex = writeBTreeIndex;
+
+        conf.SliceSize = conf.Group(0).PageSize * 4;
+
+        return conf;
+    }
+
+    struct TPartIndexSeekFixture : public benchmark::Fixture {
+        using TGroupId = NPage::TGroupId;
+
+        void SetUp(const ::benchmark::State& state) 
+        {
+            const bool groups = state.range(1);
+
+            TLayoutCook lay;
+
+            lay
+                .Col(0, 0,  NScheme::NTypeIds::Uint32)
+                .Col(0, 1,  NScheme::NTypeIds::Uint32)
+                .Col(0, 2,  NScheme::NTypeIds::Uint32)
+                .Col(0, 3,  NScheme::NTypeIds::Uint32)
+                .Col(groups ? 1 : 0, 4,  NScheme::NTypeIds::Uint32)
+                .Key({0, 1, 2});
+
+            TPartCook cook(lay, PageConf(groups ? 2 : 1, true));
+            
+            for (ui32 i = 0; (groups ? cook.GetDataBytes(0) + cook.GetDataBytes(1) : cook.GetDataBytes(0)) < 100ull*1024*1024; i++) {
+                cook.Add(*TSchemedCookRow(*lay).Col(i / 10000, i / 100 % 100, i % 100, i, i));
+            }
+
+            Eggs = cook.Finish();
+
+            const auto part = Eggs.Lone();
+
+            Cerr << "DataBytes = " << part->Stat.Bytes << " DataPages = " << IndexTools::CountMainPages(*part) << Endl;
+            Cerr << "FlatIndexBytes = " << part->GetPageSize(part->IndexPages.Groups[groups ? 1 : 0], {}) << " BTreeIndexBytes = " << part->IndexPages.BTreeGroups[groups ? 1 : 0].IndexSize << Endl;
+            Cerr << "Levels = " << part->IndexPages.BTreeGroups[groups ? 1 : 0].LevelsCount << Endl;
+
+            // 100 MB
+            UNIT_ASSERT_GE(part->Stat.Bytes, 100ull*1024*1024);
+            UNIT_ASSERT_LE(part->Stat.Bytes, 100ull*1024*1024 + 10ull*1024*1024);
+
+            GroupId = TGroupId(groups ? 1 : 0);
+        }
+
+        TPartEggs Eggs;
+        TTestEnv Env;
+        TGroupId GroupId;
+    };
+
+    struct TPartIndexIteratorFixture : public benchmark::Fixture {
+        using TGroupId = NPage::TGroupId;
+
+        void SetUp(const ::benchmark::State& state) 
+        {
+            const bool useBTree = state.range(0);
+            const bool groups = state.range(1);
+            const bool history = state.range(2);
+
+            Mass = new NTest::TMass(new NTest::TModelStd(groups), history ? 1000000 : 300000);
+            Subset = TMake(*Mass, PageConf(Mass->Model->Scheme->Families.size(), useBTree)).Mixed(0, 1, TMixerOne{ }, history ? 0.7 : 0);
+            
+            if (history) {
+                Checker = new TCheckIt(*Subset, {new TTestEnv()}, TRowVersion(0, 8));
+                CheckerReverse = new TCheckReverseIt(*Subset, {new TTestEnv()}, TRowVersion(0, 8));
+            } else {
+                Checker = new TCheckIt(*Subset, {new TTestEnv()});
+                CheckerReverse = new TCheckReverseIt(*Subset, {new TTestEnv()});
+            }
+        }
+
+        TMersenne<ui64> Rnd;
+        TAutoPtr<NTest::TMass> Mass;
+        TAutoPtr<TSubset> Subset;
+        TAutoPtr<TCheckIt> Checker;
+        TAutoPtr<TCheckReverseIt> CheckerReverse;
+    };
+}
+
+BENCHMARK_DEFINE_F(TPartIndexSeekFixture, SeekRowId)(benchmark::State& state) {
+    const bool useBTree = state.range(0);
+
+    for (auto _ : state) {
+        THolder<IIndexIter> iter;
+
+        if (useBTree) {
+            iter = MakeHolder<TPartBtreeIndexIt>(Eggs.Lone().Get(), &Env, GroupId);
+        } else {
+            iter = MakeHolder<TPartIndexIt>(Eggs.Lone().Get(), &Env, GroupId);
+        }
+
+        iter->Seek(RandomNumber<ui32>(Eggs.Lone()->Stat.Rows));    
+    }
+}
+
+BENCHMARK_DEFINE_F(TPartIndexSeekFixture, Next)(benchmark::State& state) {
+    const bool useBTree = state.range(0);
+
+    THolder<IIndexIter> iter;
+
+    if (useBTree) {
+        iter = MakeHolder<TPartBtreeIndexIt>(Eggs.Lone().Get(), &Env, GroupId);
+    } else {
+        iter = MakeHolder<TPartIndexIt>(Eggs.Lone().Get(), &Env, GroupId);
+    }
+
+    iter->Seek(RandomNumber<ui32>(Eggs.Lone()->Stat.Rows));
+
+    for (auto _ : state) {
+        if (!iter->IsValid()) {
+            iter->Seek(RandomNumber<ui32>(Eggs.Lone()->Stat.Rows));
+        }
+        iter->Next();
+    }
+}
+
+BENCHMARK_DEFINE_F(TPartIndexSeekFixture, Prev)(benchmark::State& state) {
+    const bool useBTree = state.range(0);
+
+    THolder<IIndexIter> iter;
+
+    if (useBTree) {
+        iter = MakeHolder<TPartBtreeIndexIt>(Eggs.Lone().Get(), &Env, GroupId);
+    } else {
+        iter = MakeHolder<TPartIndexIt>(Eggs.Lone().Get(), &Env, GroupId);
+    }
+
+    iter->Seek(RandomNumber<ui32>(Eggs.Lone()->Stat.Rows));
+
+    for (auto _ : state) {
+        if (!iter->IsValid()) {
+            iter->Seek(RandomNumber<ui32>(Eggs.Lone()->Stat.Rows));
+        }
+        iter->Prev();
+    }
+}
+
+BENCHMARK_DEFINE_F(TPartIndexSeekFixture, SeekKey)(benchmark::State& state) {
+    const bool useBTree = state.range(0);
+    const ESeek seek = ESeek(state.range(2));
+
+    for (auto _ : state) {
+        THolder<IIndexIter> iter;
+
+        if (useBTree) {
+            iter = MakeHolder<TPartBtreeIndexIt>(Eggs.Lone().Get(), &Env, GroupId);
+        } else {
+            iter = MakeHolder<TPartIndexIt>(Eggs.Lone().Get(), &Env, GroupId);
+        }
+
+        ui32 rowId = RandomNumber<ui32>(Eggs.Lone()->Stat.Rows);
+        TVector<TCell> key{TCell::Make(rowId / 10000), TCell::Make(rowId / 100 % 100), TCell::Make(rowId % 100)};
+        iter->Seek(seek, key, Eggs.Scheme->Keys.Get());
+    }
+}
+
+BENCHMARK_DEFINE_F(TPartIndexIteratorFixture, DoReads)(benchmark::State& state) {
+    const bool reverse = state.range(3);
+    const ui32 items = state.range(4);
+
+    for (auto _ : state) {
+        auto it = Mass->Saved.Any(Rnd);
+
+        if (reverse) {
+            CheckerReverse->Seek(*it, ESeek::Lower);
+            for (ui32 i = 1; CheckerReverse->GetReady() == EReady::Data && i < items; i++) {
+                CheckerReverse->Next();
+            }
+        } else {
+            Checker->Seek(*it, ESeek::Lower);
+            for (ui32 i = 1; Checker->GetReady() == EReady::Data && i < items; i++) {
+                Checker->Next();
+            }
+        }
+    }
+}
+
+BENCHMARK_REGISTER_F(TPartIndexSeekFixture, SeekRowId)
+    ->ArgsProduct({
+        /* b-tree */ {0, 1},
+        /* groups: */ {0, 1}})
+    ->Unit(benchmark::kMicrosecond);
+
+BENCHMARK_REGISTER_F(TPartIndexSeekFixture, Next)
+    ->ArgsProduct({
+        /* b-tree */ {0, 1},
+        /* groups: */ {0, 1}})
+    ->Unit(benchmark::kMicrosecond);
+
+BENCHMARK_REGISTER_F(TPartIndexSeekFixture, Prev)
+    ->ArgsProduct({
+        /* b-tree */ {0, 1},
+        /* groups: */ {0, 1}})
+    ->Unit(benchmark::kMicrosecond);
+
+BENCHMARK_REGISTER_F(TPartIndexSeekFixture, SeekKey)
+    ->ArgsProduct({
+        /* b-tree */ {0, 1},
+        /* groups: */ {0, 1},
+        /* ESeek: */ {0, 1, 2}})
+    ->Unit(benchmark::kMicrosecond);
+
+BENCHMARK_REGISTER_F(TPartIndexIteratorFixture, DoReads)
+    ->ArgsProduct({
+        /* b-tree */ {0, 1},
+        /* groups: */ {0, 1},
+        /* history: */ {0, 1},
+        /* reverse: */ {0, 1},
+        /* items */ {1, 10, 100}})
+    ->Unit(benchmark::kMicrosecond);
+
+}
+}
diff --git a/ydb/core/tablet_flat/benchmark/ya.make b/ydb/core/tablet_flat/benchmark/ya.make
index 41f04f436a..1ec2a13c43 100644
--- a/ydb/core/tablet_flat/benchmark/ya.make
+++ b/ydb/core/tablet_flat/benchmark/ya.make
@@ -1,10 +1,12 @@
 G_BENCHMARK()
 
-SIZE(MEDIUM)
-TIMEOUT(600)
+TAG(ya:fat)
+SIZE(LARGE)
+TIMEOUT(1200)
 
 SRCS(
     b_charge.cpp
+    b_part_index.cpp
 )
 
 PEERDIR(
diff --git a/ydb/core/tablet_flat/flat_part_btree_index_iter.h b/ydb/core/tablet_flat/flat_part_btree_index_iter.h
index 3491d58602..92c5c69f2c 100644
--- a/ydb/core/tablet_flat/flat_part_btree_index_iter.h
+++ b/ydb/core/tablet_flat/flat_part_btree_index_iter.h
@@ -116,6 +116,7 @@ public:
         , GroupId(groupId)
         , GroupInfo(part->Scheme->GetLayout(groupId))
         , Meta(groupId.IsHistoric() ? part->IndexPages.BTreeHistoric[groupId.Index] : part->IndexPages.BTreeGroups[groupId.Index])
+        , State(Reserve(Meta.LevelsCount + 1))
     {
         const static TCellsIterable EmptyKey(static_cast<const char*>(nullptr), TColumns());
         State.emplace_back(Meta, 0, GetEndRowId(), EmptyKey, EmptyKey);
diff --git a/ydb/core/tablet_flat/flat_part_loader.cpp b/ydb/core/tablet_flat/flat_part_loader.cpp
index 639131905e..f3afe7d360 100644
--- a/ydb/core/tablet_flat/flat_part_loader.cpp
+++ b/ydb/core/tablet_flat/flat_part_loader.cpp
@@ -184,8 +184,15 @@ TAutoPtr<NPageCollection::TFetch> TLoader::StageCreatePartView() noexcept
     // TODO: put index size to stat?
     // TODO: include history indexes bytes
     size_t indexesRawSize = 0;
-    for (auto indexPage : groupIndexesIds) {
-        indexesRawSize += GetPageSize(indexPage);
+    if (AppData()->FeatureFlags.GetEnableLocalDBBtreeIndex()) {
+        for (const auto &meta : BTreeGroupIndexes) {
+            indexesRawSize += meta.IndexSize;
+        }
+        // Note: although we also have flat index, it shouldn't be loaded; so let's not count it here
+    } else {
+        for (auto indexPage : groupIndexesIds) {
+            indexesRawSize += GetPageSize(indexPage);
+        }
     }
 
     auto *partStore = new TPartStore(
diff --git a/ydb/core/tablet_flat/ut_large/ut_btree_index_large.cpp b/ydb/core/tablet_flat/ut_large/ut_btree_index_large.cpp
index 2f67021480..00df27c990 100644
--- a/ydb/core/tablet_flat/ut_large/ut_btree_index_large.cpp
+++ b/ydb/core/tablet_flat/ut_large/ut_btree_index_large.cpp
@@ -1,5 +1,3 @@
-#include "flat_page_btree_index.h"
-#include "flat_page_btree_index_writer.h"
 #include "test/libs/table/test_writer.h"
 #include <ydb/core/tablet_flat/test/libs/rows/layout.h>
 #include <library/cpp/testing/unittest/registar.h>
@@ -35,7 +33,9 @@ Y_UNIT_TEST_SUITE(TBtreeIndexTPartLarge) {
 
         const auto part = eggs.Lone();
 
-        Cerr << "DataBytes = " << part->Stat.Bytes << " DataPages " << IndexTools::CountMainPages(*part) << Endl;
+        Cerr << "DataBytes = " << part->Stat.Bytes << " DataPages = " << IndexTools::CountMainPages(*part) << Endl;
+        Cerr << "FlatIndexBytes = " << part->GetPageSize(part->IndexPages.Groups[0], {}) << " BTreeIndexBytes = " << part->IndexPages.BTreeGroups[0].IndexSize << Endl;
+
         UNIT_ASSERT_GE(part->Stat.Bytes, 1ull*1024*1024*1024);
         UNIT_ASSERT_LE(part->Stat.Bytes, 1ull*1024*1024*1024 + 100*1024*1024);
 
@@ -63,7 +63,9 @@ Y_UNIT_TEST_SUITE(TBtreeIndexTPartLarge) {
 
         const auto part = eggs.Lone();
 
-        Cerr << "DataBytes = " << part->Stat.Bytes << " DataPages " << IndexTools::CountMainPages(*part) << Endl;
+        Cerr << "DataBytes = " << part->Stat.Bytes << " DataPages = " << IndexTools::CountMainPages(*part) << Endl;
+        Cerr << "FlatIndexBytes = " << part->GetPageSize(part->IndexPages.Groups[0], {}) << " BTreeIndexBytes = " << part->IndexPages.BTreeGroups[0].IndexSize << Endl;
+
         UNIT_ASSERT_GE(part->Stat.Bytes, 1ull*1024*1024*1024);
         UNIT_ASSERT_LE(part->Stat.Bytes, 1ull*1024*1024*1024 + 100*1024*1024);
 
@@ -91,12 +93,109 @@ Y_UNIT_TEST_SUITE(TBtreeIndexTPartLarge) {
 
         const auto part = eggs.Lone();
 
-        Cerr << "DataBytes = " << part->Stat.Bytes << " DataPages " << IndexTools::CountMainPages(*part) << Endl;
+        Cerr << "DataBytes = " << part->Stat.Bytes << " DataPages = " << IndexTools::CountMainPages(*part) << Endl;
+        Cerr << "FlatIndexBytes = " << part->GetPageSize(part->IndexPages.Groups[0], {}) << " BTreeIndexBytes = " << part->IndexPages.BTreeGroups[0].IndexSize << Endl;
+
         UNIT_ASSERT_GE(part->Stat.Bytes, 1ull*1024*1024*1024);
         UNIT_ASSERT_LE(part->Stat.Bytes, 1ull*1024*1024*1024 + 100*1024*1024);
 
         UNIT_ASSERT_VALUES_EQUAL(part->IndexPages.BTreeGroups[0].LevelsCount, 6);
     }
+
+    Y_UNIT_TEST(CutKeys) {
+        TLayoutCook lay;
+
+        lay
+            .Col(0, 0,  NScheme::NTypeIds::Uint64)
+            .Col(0, 1,  NScheme::NTypeIds::Uint64)
+            .Col(0, 2,  NScheme::NTypeIds::Uint64)
+            .Col(0, 3,  NScheme::NTypeIds::String)
+            .Key({0, 1, 2});
+
+        NPage::TConf conf{ true, 7 * 1024 };
+        conf.WriteBTreeIndex = true;
+
+        TPartCook cook(lay, conf);
+        
+        for (ui64 i = 0; cook.GetDataBytes(0) < 1ull*1024*1024*1024; i++) {
+            cook.Add(*TSchemedCookRow(*lay).Col(i, i, i, TString(std::to_string(i))));
+        }
+
+        TPartEggs eggs = cook.Finish();
+
+        const auto part = eggs.Lone();
+
+        Cerr << "DataBytes = " << part->Stat.Bytes << " DataPages = " << IndexTools::CountMainPages(*part) << Endl;
+        Cerr << "FlatIndexBytes = " << part->GetPageSize(part->IndexPages.Groups[0], {}) << " BTreeIndexBytes = " << part->IndexPages.BTreeGroups[0].IndexSize << Endl;
+
+        UNIT_ASSERT_GE(part->Stat.Bytes, 1ull*1024*1024*1024);
+        UNIT_ASSERT_LE(part->Stat.Bytes, 1ull*1024*1024*1024 + 100*1024*1024);
+
+        UNIT_ASSERT_VALUES_EQUAL(part->IndexPages.BTreeGroups[0].LevelsCount, 3);
+    }
+
+    Y_UNIT_TEST(Group) {
+        TLayoutCook lay;
+
+        lay
+            .Col(0, 0,  NScheme::NTypeIds::Uint32)
+            .Col(1, 1,  NScheme::NTypeIds::String)
+            .Key({0});
+
+        NPage::TConf conf{ true, 7 * 1024 };
+        conf.Group(1).PageSize = 7 * 1024;
+        conf.WriteBTreeIndex = true;
+
+        TPartCook cook(lay, conf);
+        
+        for (ui32 i = 0; cook.GetDataBytes(0) + cook.GetDataBytes(1) < 1ull*1024*1024*1024; i++) {
+            cook.Add(*TSchemedCookRow(*lay).Col(i, TString(std::to_string(i))));
+        }
+
+        TPartEggs eggs = cook.Finish();
+
+        const auto part = eggs.Lone();
+
+        Cerr << "DataBytes = " << part->Stat.Bytes << " DataPages = " << IndexTools::CountMainPages(*part) << Endl;
+        Cerr << "FlatIndexBytes = " << part->GetPageSize(part->IndexPages.Groups[1], {}) << " BTreeIndexBytes = " << part->IndexPages.BTreeGroups[1].IndexSize << Endl;
+
+        UNIT_ASSERT_GE(part->Stat.Bytes, 1ull*1024*1024*1024);
+        UNIT_ASSERT_LE(part->Stat.Bytes, 1ull*1024*1024*1024 + 100*1024*1024);
+
+        UNIT_ASSERT_VALUES_EQUAL(part->IndexPages.BTreeGroups[1].LevelsCount, 2);
+    }
+
+    Y_UNIT_TEST(History) {
+        TLayoutCook lay;
+
+        lay
+            .Col(0, 0,  NScheme::NTypeIds::Uint32)
+            .Col(0, 1,  NScheme::NTypeIds::String)
+            .Key({0});
+
+        NPage::TConf conf{ true, 7 * 1024 };
+        conf.WriteBTreeIndex = true;
+
+        TPartCook cook(lay, conf);
+        
+        for (ui32 i = 0; cook.GetDataBytes(0) < 1ull*1024*1024*1024; i++) {
+            cook.Ver({0, 2}).Add(*TSchemedCookRow(*lay).Col(i, TString(std::to_string(i))));
+            cook.Ver({0, 1}).Add(*TSchemedCookRow(*lay).Col(i, TString(std::to_string(i + 1))));
+        }
+
+        TPartEggs eggs = cook.Finish();
+
+        const auto part = eggs.Lone();
+
+        Cerr << "DataBytes = " << part->Stat.Bytes << " DataPages = " << IndexTools::CountMainPages(*part) << Endl;
+        Cerr << "FlatIndexBytes = " << part->GetPageSize(part->IndexPages.Historic[0], {}) << " BTreeIndexBytes = " << part->IndexPages.BTreeHistoric[0].IndexSize << Endl;
+
+        UNIT_ASSERT_GE(part->Stat.Bytes, 1ull*1024*1024*1024);
+        UNIT_ASSERT_LE(part->Stat.Bytes, 1ull*1024*1024*1024 + 100*1024*1024);
+
+        UNIT_ASSERT_VALUES_EQUAL(part->IndexPages.BTreeHistoric[0].LevelsCount, 3);
+    }
+
 }
 #endif