do not create temporary vector for active portions

1 files changed, 45 insertions, 36 deletions

diff --git a/ydb/core/tx/columnshard/engines/column_engine_logs.cpp b/ydb/core/tx/columnshard/engines/column_engine_logs.cpp
index b99a5951f3d..445a2d3bc54 100644
--- a/ydb/core/tx/columnshard/engines/column_engine_logs.cpp
+++ b/ydb/core/tx/columnshard/engines/column_engine_logs.cpp
@@ -127,17 +127,6 @@ bool InitInGranuleMerge(const TMark& granuleMark, std::vector<TPortionInfo>& por
     return true;
 }
 
-std::vector<const TPortionInfo*> GetActualPortions(const THashMap<ui64, TPortionInfo>& portions) {
-    std::vector<const TPortionInfo*> out;
-    out.reserve(portions.size());
-    for (auto& [portion, portionInfo] : portions) {
-        if (portionInfo.IsActive()) {
-            out.emplace_back(&portionInfo);
-        }
-    }
-    return out;
-}
-
 } // namespace
 
 
@@ -1298,30 +1287,51 @@ std::shared_ptr<TSelectInfo> TColumnEngineForLogs::Select(ui64 pathId, TSnapshot
     return out;
 }
 
-static bool NeedSplit(const std::vector<const TPortionInfo*>& actual, const TCompactionLimits& limits, bool& inserted) {
-    if (actual.size() < 2) {
-        return false;
-    }
-
+static bool NeedSplit(const THashMap<ui64, TPortionInfo>& portions, const TCompactionLimits& limits, bool& inserted) {
     ui64 sumSize = 0;
     ui64 sumMaxSize = 0;
-    auto [minPk0, maxPk0] = actual[0]->MinMaxValue(actual[0]->FirstPkColumn);
-    bool pkEqual = !!minPk0 && !!maxPk0 && arrow::ScalarEquals(*minPk0, *maxPk0);
-    for (auto* portionInfo : actual) {
-        Y_VERIFY(portionInfo);
+    size_t activeCount = 0;
+    std::shared_ptr<arrow::Scalar> minPk0;
+    std::shared_ptr<arrow::Scalar> maxPk0;
+    bool pkEqual = true;
+
+    for (const auto& [_, info] : portions) {
+        // We need only actual portions here (with empty XPlanStep:XTxId)
+        if (info.IsActive()) {
+            ++activeCount;
+        } else {
+            continue;
+        }
+
         if (pkEqual) {
-            auto [minPkCurrent, maxPkCurrent] = portionInfo->MinMaxValue(portionInfo->FirstPkColumn);
-            pkEqual = !!minPkCurrent && !!maxPkCurrent && arrow::ScalarEquals(*minPk0, *minPkCurrent)
-                && arrow::ScalarEquals(*maxPk0, *maxPkCurrent);
+            const auto [minPkCurrent, maxPkCurrent] = info.MinMaxValue(info.FirstPkColumn);
+            // Check that all pks equal to each other.
+            if ((pkEqual = bool(minPkCurrent) && bool(maxPkCurrent))) {
+                if (minPk0 && maxPk0) {
+                    pkEqual = arrow::ScalarEquals(*minPk0, *minPkCurrent) && arrow::ScalarEquals(*maxPk0, *maxPkCurrent);
+                } else {
+                    pkEqual = arrow::ScalarEquals(*minPkCurrent, *maxPkCurrent);
+
+                    minPk0 = minPkCurrent;
+                    maxPk0 = maxPkCurrent;
+                }
+            }
         }
-        auto sizes = portionInfo->BlobsSizes();
+
+        auto sizes = info.BlobsSizes();
         sumSize += sizes.first;
         sumMaxSize += sizes.second;
-        if (portionInfo->IsInserted()) {
+        if (info.IsInserted()) {
             inserted = true;
         }
     }
 
+    // Do nothing if count of active portions is less than two.
+    if (activeCount < 2) {
+        inserted = false;
+        return false;
+    }
+
     return !pkEqual && (sumMaxSize >= limits.GranuleBlobSplitSize || sumSize >= limits.GranuleOverloadSize);
 }
 
@@ -1343,18 +1353,17 @@ std::unique_ptr<TCompactionInfo> TColumnEngineForLogs::Compact(ui64& lastCompact
         const auto gi = Granules.find(*it);
         // Check granule exists.
         Y_VERIFY(gi != Granules.end());
-        // We need only actual portions here (with empty XPlanStep:XTxId)
-        if (const auto& actualPortions = GetActualPortions(gi->second->Portions); !actualPortions.empty()) {
-            bool inserted = false;
-            if (NeedSplit(actualPortions, Limits, inserted)) {
-                inGranule = false;
-                granule = *it;
-                break;
-            } else if (inserted) {
-                granule = *it;
-                break;
-            }
+
+        bool inserted = false;
+        if (NeedSplit(gi->second->Portions, Limits, inserted)) {
+            inGranule = false;
+            granule = *it;
+            break;
+        } else if (inserted) {
+            granule = *it;
+            break;
         }
+
         // Nothing to compact in the current granule. Throw it.
         it = CompactionGranules.erase(it);
     }