Stopped pushing null as arguments to TCoIf in column shards

ydb/core/kqp/opt/physical/predicate_collector.cpp

@@ -143,7 +143,14 @@ bool AbstractTreeCanBePushed(const TExprBase& expr, const TExprNode* ) {
 
 bool CheckExpressionNodeForPushdown(const TExprBase& node, const TExprNode* lambdaArg) {
     if constexpr (NKikimr::NSsa::RuntimeVersion >= 5U) {
-        if (node.Maybe<TCoIf>() || node.Maybe<TCoJust>() || node.Maybe<TCoCoalesce>()) {
+        if (node.Maybe<TCoJust>() || node.Maybe<TCoCoalesce>()) {
+            return true;
+        }
+        // Temporary fix for https://github.com/ydb-platform/ydb/issues/7967
+        else if (auto ifPred = node.Maybe<TCoIf>()) {
+            if (ifPred.ThenValue().Maybe<TCoNothing>() || ifPred.ElseValue().Maybe<TCoNothing>()) {
+                return false;
+            }
             return true;
         }
     }

ydb/core/kqp/ut/join/data/queries/tpcds34.sql

@@ -0,0 +1,38 @@
+pragma TablePathPrefix = "/Root/test/ds/";
+
+-- NB: Subquerys
+-- start query 1 in stream 0 using template query34.tpl and seed 1971067816
+select c_last_name
+       ,c_first_name
+       ,c_salutation
+       ,c_preferred_cust_flag
+       ,ss_ticket_number
+       ,cnt from
+   (select store_sales.ss_ticket_number ss_ticket_number
+          ,store_sales.ss_customer_sk ss_customer_sk
+          ,count(*) cnt
+    from store_sales as store_sales 
+    cross join date_dim as date_dim
+    cross join store as store
+    cross join household_demographics as household_demographics
+    where store_sales.ss_sold_date_sk = date_dim.d_date_sk
+    and store_sales.ss_store_sk = store.s_store_sk
+    and store_sales.ss_hdemo_sk = household_demographics.hd_demo_sk
+    and (date_dim.d_dom between 1 and 3 or date_dim.d_dom between 25 and 28)
+    and (household_demographics.hd_buy_potential = '>10000' or
+         household_demographics.hd_buy_potential = 'Unknown')
+    and household_demographics.hd_vehicle_count > 0
+    and (case when household_demographics.hd_vehicle_count > 0
+	    then household_demographics.hd_dep_count/ household_demographics.hd_vehicle_count
+	    else null
+	    end)  > 1.2
+    and date_dim.d_year in (2000,2000+1,2000+2)
+    and store.s_county in ('Salem County','Terrell County','Arthur County','Oglethorpe County',
+                           'Lunenburg County','Perry County','Halifax County','Sumner County')
+    group by store_sales.ss_ticket_number,store_sales.ss_customer_sk) dn 
+    cross join customer as customer
+    where ss_customer_sk = c_customer_sk
+      and cnt between 15 and 20
+    order by c_last_name,c_first_name,c_salutation,c_preferred_cust_flag desc, ss_ticket_number;
+
+-- end query 1 in stream 0 using template query34.tpl

ydb/core/kqp/ut/join/kqp_join_order_ut.cpp

@@ -331,6 +331,10 @@ Y_UNIT_TEST_SUITE(KqpJoinOrder) {
         ExecuteJoinOrderTestDataQueryWithStats("queries/tpcds16.sql", "stats/tpcds1000s.json", StreamLookupJoin, ColumnStore);       
     }
 
+    Y_UNIT_TEST_XOR_OR_BOTH_FALSE(TPCDS34, StreamLookupJoin, ColumnStore) {
+        ExecuteJoinOrderTestDataQueryWithStats("queries/tpcds34.sql", "stats/tpcds1000s.json", StreamLookupJoin, ColumnStore);       
+    }
+
     Y_UNIT_TEST_XOR_OR_BOTH_FALSE(TPCDS61, StreamLookupJoin, ColumnStore) {
         ExecuteJoinOrderTestDataQueryWithStats("queries/tpcds61.sql", "stats/tpcds1000s.json", StreamLookupJoin, ColumnStore);       
     }

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

@@ -2054,6 +2054,36 @@ Y_UNIT_TEST_SUITE(KqpOlap) {
     }
 */
 
+    // Unit test for https://github.com/ydb-platform/ydb/issues/7967
+    Y_UNIT_TEST(PredicatePushdownNulls) {
+        auto settings = TKikimrSettings()
+            .SetWithSampleTables(false);
+
+        TKikimrRunner kikimr(settings);
+
+        TStreamExecScanQuerySettings scanSettings;
+        scanSettings.Explain(true);
+
+        TLocalHelper(kikimr.GetTestServer()).CreateTestOlapTable();
+        WriteTestData(kikimr, "/Root/olapStore/olapTable", 10000, 3000000, 10);
+
+        auto tableClient = kikimr.GetTableClient();
+
+        TString query = R"(
+                SELECT `timestamp` FROM `/Root/olapStore/olapTable` WHERE
+                    (case when level > 0
+	                    then level
+	                    else null
+	                end) > 0;
+        )";
+
+        auto it = tableClient.StreamExecuteScanQuery(query).GetValueSync();
+        // Check for successful execution
+        auto streamPart = it.ReadNext().GetValueSync();
+
+        UNIT_ASSERT(streamPart.IsSuccess());
+    }
+
     Y_UNIT_TEST(PredicatePushdownCastErrors) {
         auto settings = TKikimrSettings()
             .SetWithSampleTables(false);