Count Rounds from 1 again to prevent N+1 rounds instead of requested N (#19154) (#20237)

Author: vitalif

ydb/core/tx/datashard/build_index/local_kmeans.cpp

@@ -379,6 +379,7 @@ class TLocalKMeansScan: public TActor<TLocalKMeansScan>, public IActorExceptionH
             }
             bool ok = Clusters->SetClusters(std::move(rows));
             Y_ENSURE(ok);
+            Clusters->SetRound(1);
             return false; // do KMEANS
         }
 

ydb/core/tx/datashard/build_index/prefix_kmeans.cpp

@@ -425,6 +425,7 @@ class TPrefixKMeansScan: public TActor<TPrefixKMeansScan>, public IActorExceptio
             }
             bool ok = Clusters->SetClusters(std::move(rows));
             Y_ENSURE(ok);
+            Clusters->SetRound(1);
             return false; // do KMEANS
         }
 

ydb/core/tx/schemeshard/schemeshard_build_index__progress.cpp

@@ -1090,12 +1090,12 @@ struct TSchemeShard::TIndexBuilder::TTxProgress: public TSchemeShard::TIndexBuil
             if (buildInfo.KMeans.Rounds > 1) {
                 LOG_D("FillVectorIndex Recompute " << buildInfo.DebugString());
                 buildInfo.KMeans.State = TIndexBuildInfo::TKMeans::Recompute;
-                buildInfo.KMeans.Round = 0;
+                buildInfo.KMeans.Round = 1;
                 // Initialize Clusters
                 NIceDb::TNiceDb db(txc.DB);
                 buildInfo.Sample.MakeStrictTop(buildInfo.KMeans.K);
                 Self->PersistBuildIndexSampleToClusters(db, buildInfo);
-                buildInfo.Clusters->SetRound(0);
+                buildInfo.Clusters->SetRound(1);
                 PersistKMeansState(txc, buildInfo);
                 Progress(BuildId);
             } else {

ydb/core/tx/schemeshard/ut_index_build/ut_vector_index_build.cpp

@@ -549,8 +549,8 @@ Y_UNIT_TEST_SUITE (VectorIndexBuildTest) {
         UNIT_ASSERT_VALUES_EQUAL(readRows, expectedReadRows);
         UNIT_ASSERT_VALUES_EQUAL(readBytes, expectedReadBytes);
 
-        // every RECOMPUTE round reads table once, no writes; there are 4 recompute rounds:
-        for (ui32 round = 0; round < 4; round++) {
+        // every RECOMPUTE round reads table once, no writes; there are 3 recompute rounds:
+        for (ui32 round = 0; round < 3; round++) {
             for (ui32 shard = 0; shard < 3; shard++) {
                 runtime.WaitFor("recomputeK", [&]{ return recomputeKBlocker.size(); });
                 recomputeKBlocker.Unblock();
@@ -621,9 +621,9 @@ Y_UNIT_TEST_SUITE (VectorIndexBuildTest) {
         expectedUploadRows += level2clusters;
         expectedUploadBytes += level2clusters * levelRowBytes;
         if (smallScanBuffer) {
-            // KMEANS reads build table 6 times (SAMPLE + KMEANS * 4 + UPLOAD):
-            expectedReadRows += tableRows * 6;
-            expectedReadBytes += buildBytes * 6;
+            // KMEANS reads build table 5 times (SAMPLE + KMEANS * 3 + UPLOAD):
+            expectedReadRows += tableRows * 5;
+            expectedReadBytes += buildBytes * 5;
         } else {
             // KMEANS reads build table once:
             expectedReadRows += tableRows;