wangbo commented on code in PR #8834:
URL: https://github.com/apache/incubator-doris/pull/8834#discussion_r857408776


##########
be/src/olap/rowset/segment_v2/segment_iterator.cpp:
##########
@@ -646,75 +669,82 @@ void SegmentIterator::_vec_init_lazy_materialization() {
         if (!del_cond_id_set.empty()) {
             short_cir_pred_col_id_set.insert(del_cond_id_set.begin(), 
del_cond_id_set.end());
             pred_column_ids.insert(del_cond_id_set.begin(), 
del_cond_id_set.end());
-            _is_all_column_basic_type = false;
 
             for (auto cid : del_cond_id_set) {
                 _is_pred_column[cid] = true;
             }
         }
 
-        if (_schema.column_ids().size() > pred_column_ids.size()) {
-            for (auto cid : _schema.column_ids()) {
-                if (!_is_pred_column[cid]) {
-                    _non_predicate_columns.push_back(cid);
-                    is_non_predicate_column_exists = true;
-
-                    // todo(wb) make a cost-based lazy-materialization 
framework
-                    // check non-pred column type to decide whether using 
lazy-materialization
-                    FieldType type = _schema.column(cid)->type();
-                    if (_is_all_column_basic_type &&
-                        (type == OLAP_FIELD_TYPE_HLL || type == 
OLAP_FIELD_TYPE_OBJECT ||
-                         type == OLAP_FIELD_TYPE_VARCHAR || type == 
OLAP_FIELD_TYPE_CHAR ||
-                         type == OLAP_FIELD_TYPE_STRING)) {
-                        _is_all_column_basic_type = false;
-                    }
-                }
-            }
-        }
-
         _vec_pred_column_ids.assign(vec_pred_col_id_set.cbegin(), 
vec_pred_col_id_set.cend());
-        _short_cir_pred_column_ids.assign(short_cir_pred_col_id_set.cbegin(),
-                                          short_cir_pred_col_id_set.cend());
-    } else {
-        _is_all_column_basic_type = false;
-        is_non_predicate_column_exists = true;
+        _short_cir_pred_column_ids.assign(short_cir_pred_col_id_set.cbegin(), 
short_cir_pred_col_id_set.cend());
+    }
+
+    if (!_vec_pred_column_ids.empty()) {
+        _is_need_vec_eval = true;
+    }
+    if (!_short_cir_pred_column_ids.empty()) {
+        _is_need_short_eval = true;
+    }
+
+    // Step 2: check non-predicate read costs to determine whether need lazy 
materialization
+    // fill _non_predicate_columns.
+    // note(wb) For block schema, query layer and storage layer may have some 
diff
+    //   query layer block schema not contains delete column, but storage 
layer appends delete column to end of block schema
+    //   When output block to query layer, delete column can be skipped.
+    //  _schema.column_ids() stands for storage layer block schema, so it 
contains delete columnid
+    //  we just regard delete column as common pred column here.
+    if (_schema.column_ids().size() > pred_column_ids.size()) {
         for (auto cid : _schema.column_ids()) {
-            _non_predicate_columns.push_back(cid);
+            if (!_is_pred_column[cid]) {
+                _non_predicate_columns.push_back(cid);
+                FieldType type = _schema.column(cid)->type();
+                
+                // todo(wb) maybe we can make read char type faster
+                // todo(wb) support map/array type
+                // todo(wb) consider multiple integer columns cost, such as 
1000 columns, maybe lazy materialization faster
+                if (!_lazy_materialization_read && 
+                        (_is_need_vec_eval || _is_need_short_eval) && // only 
when pred exists, we need to consider lazy materialization
+                        (type == OLAP_FIELD_TYPE_HLL || type == 
OLAP_FIELD_TYPE_OBJECT || 
+                        type == OLAP_FIELD_TYPE_VARCHAR || type == 
OLAP_FIELD_TYPE_CHAR || type == OLAP_FIELD_TYPE_STRING ||
+                        type == OLAP_FIELD_TYPE_BOOL || type == 
OLAP_FIELD_TYPE_DATE || type == OLAP_FIELD_TYPE_DATETIME ||

Review Comment:
   I didn't do performance test.
   But bool is read from a runlenDecoder, it means bool can only be read row by 
row, can not in batch.



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