fix snapshot tracing signals (#7821)

Author: ivanmorozov333

ydb/core/tx/columnshard/columnshard_impl.cpp

@@ -189,13 +189,14 @@ NOlap::TSnapshot TColumnShard::GetMinReadSnapshot() const {
     ui64 delayMillisec = GetMaxReadStaleness().MilliSeconds();
     ui64 passedStep = GetOutdatedStep();
     ui64 minReadStep = (passedStep > delayMillisec ? passedStep - delayMillisec : 0);
-    Counters.GetRequestsTracingCounters()->OnDefaultMinSnapshotInstant(TInstant::MilliSeconds(minReadStep));
 
     if (auto ssClean = InFlightReadsTracker.GetSnapshotToClean()) {
         if (ssClean->GetPlanStep() < minReadStep) {
+            Counters.GetRequestsTracingCounters()->OnDefaultMinSnapshotInstant(TInstant::MilliSeconds(ssClean->GetPlanStep()));
             return *ssClean;
         }
     }
+    Counters.GetRequestsTracingCounters()->OnDefaultMinSnapshotInstant(TInstant::MilliSeconds(minReadStep));
     return NOlap::TSnapshot::MaxForPlanStep(minReadStep);
 }
 

ydb/core/tx/columnshard/inflight_request_tracker.cpp

@@ -23,7 +23,6 @@ void TInFlightReadsTracker::RemoveInFlightRequest(ui64 cookie, const NOlap::TVer
             AFL_VERIFY(it != SnapshotsLive.end());
             if (it->second.DelRequest(cookie, now)) {
                 SnapshotsLive.erase(it);
-                Counters->OnSnapshotsInfo(SnapshotsLive.size(), GetSnapshotToClean());
             }
         }
 
@@ -33,6 +32,7 @@ void TInFlightReadsTracker::RemoveInFlightRequest(ui64 cookie, const NOlap::TVer
             tracker->FreeBlob(committedBlob.GetBlobRange().GetBlobId());
         }
     }
+    Counters->OnSnapshotsInfo(SnapshotsLive.size(), GetSnapshotToClean());
 
     RequestsMeta.erase(cookie);
 }
@@ -110,6 +110,7 @@ std::unique_ptr<NTabletFlatExecutor::ITransaction> TInFlightReadsTracker::Ping(
     for (auto&& i : snapshotsToFree) {
         SnapshotsLive.erase(i);
     }
+    Counters->OnSnapshotsInfo(SnapshotsLive.size(), GetSnapshotToClean());
     if (snapshotsToFree.size() || snapshotsToSave.size()) {
         NYDBTest::TControllers::GetColumnShardController()->OnRequestTracingChanges(snapshotsToSave, snapshotsToFree);
         return std::make_unique<TTransactionSavePersistentSnapshots>(self, std::move(snapshotsToSave), std::move(snapshotsToFree));