Fix flaky KqpOlapScheme.DropTable (#6795)

Author: swalrus1

.github/config/muted_ya.txt

@@ -19,7 +19,6 @@ ydb/core/kqp/ut/scheme KqpOlapScheme.TenThousandColumns
 ydb/core/kqp/ut/scheme KqpOlap.OlapRead_GenericQuerys
 ydb/core/kqp/ut/scheme KqpOlap.OlapRead_StreamGenericQuery
 ydb/core/kqp/ut/scheme KqpOlap.OlapRead_UsesGenericQueryOnJoinWithDataShardTable
-ydb/core/kqp/ut/scheme KqpOlapScheme.DropTable
 ydb/core/kqp/ut/scheme KqpScheme.AlterAsyncReplication
 ydb/core/kqp/ut/scheme KqpScheme.QueryWithAlter
 ydb/core/kqp/ut/scheme [14/50]*

ydb/core/kqp/ut/common/columnshard.cpp

@@ -130,6 +130,14 @@ namespace NKqp {
         }
     }
 
+    void TTestHelper::WaitTabletDeletionInHive(ui64 tabletId, TDuration duration) {
+        auto deadline = TInstant::Now() + duration;
+        while (GetKikimr().GetTestClient().TabletExistsInHive(&GetRuntime(), tabletId) && TInstant::Now() <= deadline) {
+            Cerr << "WaitTabletDeletionInHive: wait until " << tabletId << " is deleted" << Endl;
+            Sleep(TDuration::Seconds(1));
+        }
+    }
+
     TString TTestHelper::TColumnSchema::BuildQuery() const {
         TStringBuilder str;
         str << Name << ' ';

ydb/core/kqp/ut/common/columnshard.h

@@ -82,6 +82,7 @@ namespace NKqp {
         void BulkUpsert(const TColumnTable& table, std::shared_ptr<arrow::RecordBatch> batch, const Ydb::StatusIds_StatusCode& opStatus = Ydb::StatusIds::SUCCESS);
         void ReadData(const TString& query, const TString& expected, const NYdb::EStatus opStatus = NYdb::EStatus::SUCCESS);
         void RebootTablets(const TString& tableName);
+        void WaitTabletDeletionInHive(ui64 tabletId, TDuration duration);
     };
 
 }

ydb/core/kqp/ut/scheme/kqp_scheme_ut.cpp

@@ -6467,6 +6467,7 @@ Y_UNIT_TEST_SUITE(KqpOlapScheme) {
         }
         testHelper.DropTable("/Root/ColumnTableTest");
         for (auto tablet: tabletIds) {
+            testHelper.WaitTabletDeletionInHive(tablet, TDuration::Seconds(5));
             UNIT_ASSERT_C(!testHelper.GetKikimr().GetTestClient().TabletExistsInHive(&testHelper.GetRuntime(), tablet), ToString(tablet) + " is alive");
         }
     }