Fix olap reads in data query (#12463)

Author: nikvas0

ydb/core/kqp/executer_actor/kqp_data_executer.cpp

@@ -2007,7 +2007,7 @@ class TKqpDataExecuter : public TKqpExecuterBase<TKqpDataExecuter, EExecType::Da
                         default:
                             YQL_ENSURE(false, "unknown source type");
                     }
-                } else if (StreamResult && stageInfo.Meta.IsOlap() && stage.SinksSize() == 0) {
+                } else if ((AllowOlapDataQuery || StreamResult) && stageInfo.Meta.IsOlap() && stage.SinksSize() == 0) {
                     BuildScanTasksFromShards(stageInfo);
                 } else if (stageInfo.Meta.IsSysView()) {
                     BuildSysViewScanTasks(stageInfo);
@@ -2161,7 +2161,7 @@ class TKqpDataExecuter : public TKqpExecuterBase<TKqpDataExecuter, EExecType::Da
     void HandleResolve(TEvKqpExecuter::TEvTableResolveStatus::TPtr& ev) {
         if (!TBase::HandleResolve(ev)) return;
 
-        if (StreamResult) {
+        if (StreamResult || AllowOlapDataQuery) {
             TSet<ui64> shardIds;
             for (auto& [stageId, stageInfo] : TasksGraph.GetStagesInfo()) {
                 if (stageInfo.Meta.IsOlap()) {

ydb/core/kqp/ut/olap/kqp_olap_ut.cpp

@@ -1867,10 +1867,10 @@ Y_UNIT_TEST_SUITE(KqpOlap) {
                 ORDER BY CounterID, WatchID
             )";
 
-            auto it = tableClient.StreamExecuteScanQuery(query).GetValueSync();
+            auto it = session.ExecuteDataQuery(query, TTxControl::BeginTx(TTxSettings::SerializableRW()).CommitTx()).GetValueSync();
 
             UNIT_ASSERT_C(it.IsSuccess(), it.GetIssues().ToString());
-            TString result = StreamResultToYson(it);
+            TString result = FormatResultSetYson(it.GetResultSet(0));
             Cout << result << Endl;
             CompareYson(result, R"([[15;0];[15;1]])");
         }