diff --git a/src/Storages/MergeTree/MergeTask.cpp b/src/Storages/MergeTree/MergeTask.cpp
index 9a1e749734c..5c993504245 100644
--- a/src/Storages/MergeTree/MergeTask.cpp
+++ b/src/Storages/MergeTree/MergeTask.cpp
@@ -952,6 +952,7 @@ MergeTask::VerticalMergeRuntimeContext::PreparedColumnPipeline MergeTask::Vertic
             indexes_to_recalc = MergeTreeIndexFactory::instance().getMany(indexes_it->second);
 
             auto indices_expression_dag = indexes_it->second.getSingleExpressionForIndices(global_ctx->metadata_snapshot->getColumns(), global_ctx->data->getContext())->getActionsDAG().clone();
+            indices_expression_dag.addMaterializingOutputActions(); /// Const columns cannot be written without materialization.
             auto calculate_indices_expression_step = std::make_unique<ExpressionStep>(
                 merge_column_query_plan.getCurrentDataStream(),
                 std::move(indices_expression_dag));