scanner simple speed up (#13281)

Author: ivanmorozov333

ydb/core/tx/columnshard/engines/reader/simple_reader/iterator/scanner.cpp

@@ -18,9 +18,6 @@ void TScanHead::OnSourceReady(const std::shared_ptr<IDataSource>& source, std::s
     Context->GetCommonContext()->GetCounters().OnSourceFinished(
         source->GetRecordsCount(), source->GetUsedRawBytes(), tableExt ? tableExt->num_rows() : 0);
 
-    if ((!tableExt || !tableExt->num_rows()) && Context->GetCommonContext()->GetReadMetadata()->HasLimit() && InFlightLimit < MaxInFlight) {
-        InFlightLimit = 2 * InFlightLimit;
-    }
     source->MutableStageResult().SetResultChunk(std::move(tableExt), startIndex, recordsCount);
     while (FetchingSources.size()) {
         auto frontSource = FetchingSources.front();
@@ -59,13 +56,18 @@ void TScanHead::OnSourceReady(const std::shared_ptr<IDataSource>& source, std::s
         AFL_VERIFY(FetchingSourcesByIdx.erase(frontSource->GetSourceIdx()));
         FetchingSources.pop_front();
         frontSource->ClearResult();
-        if (Context->GetCommonContext()->GetReadMetadata()->HasLimit() && FetchingSources.size() && frontSource->GetResultRecordsCount()) {
-            FinishedSources.emplace(frontSource);
-            while (FinishedSources.size() && (*FinishedSources.begin())->GetFinish() < FetchingSources.front()->GetStart()) {
-                auto fetchingSource = FetchingSources.front();
+        if (Context->GetCommonContext()->GetReadMetadata()->HasLimit() && SortedSources.size() && frontSource->GetResultRecordsCount()) {
+            AFL_VERIFY(FetchingInFlightSources.erase(frontSource));
+            AFL_VERIFY(FinishedSources.emplace(frontSource).second);
+            while (FinishedSources.size() && (*FinishedSources.begin())->GetFinish() < SortedSources.front()->GetStart()) {
                 auto finishedSource = *FinishedSources.begin();
+                if (!finishedSource->GetResultRecordsCount() && Context->GetCommonContext()->GetReadMetadata()->HasLimit() &&
+                    InFlightLimit < MaxInFlight) {
+                    InFlightLimit = 2 * InFlightLimit;
+                }
                 FetchedCount += finishedSource->GetResultRecordsCount();
                 FinishedSources.erase(FinishedSources.begin());
+                --IntervalsInFlightCount;
                 AFL_DEBUG(NKikimrServices::TX_COLUMNSHARD)("event", "source_finished")("source_id", finishedSource->GetSourceId())(
                     "source_idx", finishedSource->GetSourceIdx())("limit", Context->GetCommonContext()->GetReadMetadata()->GetLimitRobust())(
                     "fetched", finishedSource->GetResultRecordsCount());
@@ -119,14 +121,41 @@ TConclusion<bool> TScanHead::BuildNextInterval() {
     if (!Context->IsActive()) {
         return false;
     }
+    if (InFlightLimit <= IntervalsInFlightCount) {
+        return false;
+    }
+    if (SortedSources.size() == 0) {
+        return false;
+    }
     bool changed = false;
-    while (SortedSources.size() && FetchingSources.size() < InFlightLimit) {
+    ui32 inFlightCountLocal = 0;
+    if (SortedSources.size()) {
+        for (auto it = FetchingInFlightSources.begin(); it != FetchingInFlightSources.end(); ++it) {
+            if ((*it)->GetFinish() < SortedSources.front()->GetStart()) {
+                ++inFlightCountLocal;
+            }
+        }
+    }
+    AFL_VERIFY(IntervalsInFlightCount == inFlightCountLocal)("count_global", IntervalsInFlightCount)("count_local", inFlightCountLocal);
+    while (SortedSources.size() && inFlightCountLocal < InFlightLimit) {
         SortedSources.front()->StartProcessing(SortedSources.front());
         FetchingSources.emplace_back(SortedSources.front());
         FetchingSourcesByIdx.emplace(SortedSources.front()->GetSourceIdx(), SortedSources.front());
+        AFL_VERIFY(FetchingInFlightSources.emplace(SortedSources.front()).second);
         SortedSources.pop_front();
+        if (SortedSources.size()) {
+            ui32 inFlightCountLocalNew = 0;
+            for (auto it = FetchingInFlightSources.begin(); it != FetchingInFlightSources.end(); ++it) {
+                if ((*it)->GetFinish() < SortedSources.front()->GetStart()) {
+                    ++inFlightCountLocalNew;
+                }
+            }
+            AFL_VERIFY(inFlightCountLocal <= inFlightCountLocalNew);
+            inFlightCountLocal = inFlightCountLocalNew;
+        }
         changed = true;
     }
+    IntervalsInFlightCount = inFlightCountLocal;
     return changed;
 }
 

ydb/core/tx/columnshard/engines/reader/simple_reader/iterator/scanner.h

@@ -29,6 +29,8 @@ class TScanHead {
     std::deque<std::shared_ptr<IDataSource>> SortedSources;
     std::deque<std::shared_ptr<IDataSource>> FetchingSources;
     std::set<std::shared_ptr<IDataSource>, IDataSource::TCompareFinishForScanSequence> FinishedSources;
+    std::set<std::shared_ptr<IDataSource>, IDataSource::TCompareFinishForScanSequence> FetchingInFlightSources;
+    TPositiveControlInteger IntervalsInFlightCount;
     ui64 FetchedCount = 0;
     ui64 InFlightLimit = 1;
     ui64 MaxInFlight = 256;

ydb/library/accessor/positive_integer.cpp

@@ -35,4 +35,10 @@ ui64 TPositiveControlInteger::Val() const {
     return Value;
 }
 
-}
+}
+
+template<>
+void Out<NKikimr::TPositiveControlInteger>(IOutputStream& o,
+    typename TTypeTraits<NKikimr::TPositiveControlInteger>::TFuncParam x) {
+    o << x.Val();
+}

ydb/library/accessor/positive_integer.h

@@ -1,5 +1,7 @@
 #pragma once
 #include <util/system/types.h>
+#include <util/stream/output.h>
+#include <util/generic/typetraits.h>
 
 namespace NKikimr {
 
@@ -11,6 +13,10 @@ class TPositiveControlInteger {
     TPositiveControlInteger(const ui64 value)
         : Value(value) {
 
+    }
+    TPositiveControlInteger(const ui32 value)
+        : Value(value) {
+
     }
     TPositiveControlInteger(const i64 value);
     ui64 Add(const ui64 value);
@@ -37,4 +43,4 @@ class TPositiveControlInteger {
     }
 };
 
-}
+}