Add different stat histogram test cases (#4881)

Author: kungasc

ydb/core/tablet_flat/benchmark/b_part.cpp

@@ -216,9 +216,9 @@ BENCHMARK_DEFINE_F(TPartFixture, DoCharge)(benchmark::State& state) {
         auto key1 = tool.KeyCells(Mass->Saved[row1]);
         auto key2 = tool.KeyCells(Mass->Saved[row2]);
         if (reverse) {
-            ChargeRangeReverse(&Env, key1, key2, run, *Subset->Scheme->Keys, tags, items, 0);
+            ChargeRangeReverse(&Env, key1, key2, run, *Subset->Scheme->Keys, tags, items, 0, true);
         } else {
-            ChargeRange(&Env, key1, key2, run, *Subset->Scheme->Keys, tags, items, 0);
+            ChargeRange(&Env, key1, key2, run, *Subset->Scheme->Keys, tags, items, 0, true);
         }
     }
 }

ydb/core/tablet_flat/flat_part_charge_range.h

@@ -11,10 +11,10 @@ namespace {
 
 bool ChargeRange(IPages *env, const TCells key1, const TCells key2,
             const TRun &run, const TKeyCellDefaults &keyDefaults, TTagsRef tags,
-            ui64 items, ui64 bytes, bool includeHistory = false) noexcept;
+            ui64 items, ui64 bytes, bool includeHistory) noexcept;
 
 bool ChargeRangeReverse(IPages *env, const TCells key1, const TCells key2,
             const TRun &run, const TKeyCellDefaults &keyDefaults, TTagsRef tags,
-            ui64 items, ui64 bytes, bool includeHistory = false) noexcept;
+            ui64 items, ui64 bytes, bool includeHistory) noexcept;
 
 }

ydb/core/tablet_flat/flat_part_index_iter_bree_index.h

@@ -274,6 +274,18 @@ class TPartGroupBtreeIndexIter : public IPartGroupIndexIter {
         return State.back().BeginKey.Iter().At(index);
     }
 
+    void GetKeyCells(TSmallVec<TCell>& keyCells) const override {
+        keyCells.clear();
+
+        Y_ABORT_UNLESS(IsLeaf());
+
+        auto iter = State.back().BeginKey.Iter();
+        for (TPos pos : xrange(iter.Count())) {
+            Y_UNUSED(pos);
+            keyCells.push_back(iter.Next());
+        }
+    }
+
 private:
     template<typename TSeek>
     EReady DoSeek(TSeek seek) {

ydb/core/tablet_flat/flat_part_index_iter_iface.h

@@ -24,6 +24,7 @@ namespace NKikimr::NTable {
 
         virtual TPos GetKeyCellsCount() const = 0;
         virtual TCell GetKeyCell(TPos index) const = 0;
+        virtual void GetKeyCells(TSmallVec<TCell>& keyCells) const = 0;
 
         virtual ~IPartGroupIndexIter() = default;
     };

ydb/core/tablet_flat/flat_stat_table_mixed_index.h

@@ -14,12 +14,16 @@ inline bool BuildStatsMixedIndex(const TSubset& subset, TStats& stats, ui64 rowC
     TDataStats iteratorStats = { };
     TStatsIterator statsIterator(subset.Scheme->Keys);
 
+    // Note: B-Tree index uses resolution to skip huge nodes
+    // doesn't work well with intersecting SSTs
+    const ui32 resolutionDivider = 5;
+
     // Make index iterators for all parts
     bool started = true;
     for (const auto& part : subset.Flatten) {
         stats.IndexSize.Add(part->IndexesRawSize, part->Label.Channel());
         TAutoPtr<TStatsScreenedPartIterator> iter = new TStatsScreenedPartIterator(part, env, subset.Scheme->Keys, part->Small, part->Large, 
-            rowCountResolution, dataSizeResolution);
+            rowCountResolution / resolutionDivider, dataSizeResolution / resolutionDivider);
         auto ready = iter->Start();
         if (ready == EReady::Page) {
             started = false;

ydb/core/tablet_flat/test/libs/table/test_mixer.h

@@ -1,5 +1,6 @@
 #pragma once
 
+#include <util/generic/utility.h>
 #include <util/random/mersenne.h>
 
 namespace NKikimr {
@@ -16,44 +17,46 @@ namespace NTest {
     };
 
     struct TMixerRnd {
-        TMixerRnd(ui32 num) : Num(num) { }
+        TMixerRnd(ui32 buckets) 
+            : Buckets(buckets) 
+        {
+        }
 
         ui32 operator()(const TRow&) noexcept
         {
-            return Random.Uniform(Num);
+            return Random.Uniform(Buckets);
         }
 
     private:
-        const ui32 Num = 1;
+        const ui32 Buckets = 1;
         TMersenne<ui64> Random;
     };
 
     struct TMixerSeq {
-        TMixerSeq(ui32 num, ui64 rows)
-            : Num(num)
-            , Base(rows / num)
-            , Skip(rows % num)
+        TMixerSeq(ui32 buckets, ui64 rows)
+            : Buckets(buckets)
+            , RowsPerBucket(rows / buckets)
+            , Skip(rows % buckets)
         {
-
         }
 
         ui32 operator()(const TRow&) noexcept
         {
-            if (Buck-- == 0) {
-                ui64 one = (Skip && Skip > Random.Uniform(Num) ? 1 : 0);
+            if (CurrentBucketRemainingRows-- == 0) { // start next bucket with CurrentBucketRemainingRows rows
+                ui64 one = (Skip && Skip > Random.Uniform(Buckets) ? 1 : 0);
 
-                Buck = Base + one, Skip -= one, Hash++;
+                CurrentBucketRemainingRows = RowsPerBucket + one, Skip -= one, CurrentBucket++;
             }
 
-            return Min(Hash, Num - 1);
+            return Min(CurrentBucket, Buckets - 1);
         }
 
     private:
-        const ui32 Num = 1;
-        ui64 Base = Max<ui64>();
-        ui64 Skip = 0;
-        ui64 Buck = 0;
-        ui32 Hash = Max<ui32>();
+        const ui32 Buckets;
+        ui64 RowsPerBucket;
+        ui64 Skip;
+        ui64 CurrentBucketRemainingRows = 0;
+        ui32 CurrentBucket = Max<ui32>();
         TMersenne<ui64> Random;
     };
 }