[Enhancement] Support default values for complex types (ARRAY, MAP, STRUCT)

be/src/agent/agent_task.cpp

@@ -218,11 +218,16 @@ void run_drop_tablet_task(const std::shared_ptr<DropTabletAgentTaskRequest>& age
 }
 
 void run_create_tablet_task(const std::shared_ptr<CreateTabletAgentTaskRequest>& agent_task_req, ExecEnv* exec_env) {
-    const auto& create_tablet_req = agent_task_req->task_req;
+    TCreateTabletReq create_tablet_req = agent_task_req->task_req;
     TFinishTaskRequest finish_task_request;
     TStatusCode::type status_code = TStatusCode::OK;
     std::vector<std::string> error_msgs;
 
+    Status preprocess_status = preprocess_default_expr_for_tcolumns(create_tablet_req.tablet_schema.columns);
+    if (!preprocess_status.ok()) {
+        LOG(WARNING) << "Failed to preprocess default_expr in CREATE TABLE: " << preprocess_status.to_string();
+    }
+
     auto tablet_type = create_tablet_req.tablet_type;
     Status create_status;
 
@@ -633,6 +638,12 @@ void run_update_schema_task(const std::shared_ptr<UpdateSchemaTaskRequest>& agen
     for (auto uid : tcolumn_param.sort_key_uid) {
         pcolumn_param.add_sort_key_uid(uid);
     }
+
+    Status preprocess_status = preprocess_default_expr_for_tcolumns(tcolumn_param.columns);
+    if (!preprocess_status.ok()) {
+        LOG(WARNING) << "Failed to preprocess default_expr in UPDATE_SCHEMA task: " << preprocess_status;
+    }
+
     Status st;
     for (auto& tcolumn : tcolumn_param.columns) {
         uint32_t col_unique_id = tcolumn.col_unique_id;

be/src/exec/olap_meta_scanner.cpp

@@ -17,6 +17,7 @@
 #include <memory>
 
 #include "exec/olap_meta_scan_node.h"
+#include "storage/metadata_util.h"
 #include "storage/storage_engine.h"
 #include "storage/tablet.h"
 #include "storage/tablet_manager.h"
@@ -58,8 +59,14 @@ Status OlapMetaScanner::_init_meta_reader_params() {
     if (_reader_params.tablet_schema == nullptr) {
         if (_parent->_meta_scan_node.__isset.columns && !_parent->_meta_scan_node.columns.empty() &&
             (_parent->_meta_scan_node.columns[0].col_unique_id >= 0)) {
-            _reader_params.tablet_schema =
-                    TabletSchema::copy(*_tablet->tablet_schema(), _parent->_meta_scan_node.columns);
+            auto columns_copy = _parent->_meta_scan_node.columns;
+            Status preprocess_status = preprocess_default_expr_for_tcolumns(columns_copy);
+            if (!preprocess_status.ok()) {
+                LOG(WARNING) << "Failed to preprocess default_expr in OlapMetaScanner: "
+                             << preprocess_status.to_string();
+            }
+
+            _reader_params.tablet_schema = TabletSchema::copy(*_tablet->tablet_schema(), columns_copy);
         } else {
             _reader_params.tablet_schema = _tablet->tablet_schema();
         }

be/src/exec/pipeline/scan/olap_chunk_source.cpp

@@ -41,11 +41,11 @@
 #include "storage/chunk_helper.h"
 #include "storage/column_predicate_rewriter.h"
 #include "storage/index/vector/vector_search_option.h"
+#include "storage/metadata_util.h"
 #include "storage/predicate_parser.h"
 #include "storage/projection_iterator.h"
 #include "storage/runtime_range_pruner.hpp"
 #include "storage/storage_engine.h"
-#include "storage/tablet_index.h"
 #include "types/logical_type.h"
 #include "util/runtime_profile.h"
 #include "util/table_metrics.h"
@@ -560,8 +560,13 @@ Status OlapChunkSource::_init_olap_reader(RuntimeState* runtime_state) {
         if (_scan_node->thrift_olap_scan_node().__isset.columns_desc &&
             !_scan_node->thrift_olap_scan_node().columns_desc.empty() &&
             _scan_node->thrift_olap_scan_node().columns_desc[0].col_unique_id >= 0) {
-            _tablet_schema =
-                    TabletSchema::copy(*_tablet->tablet_schema(), _scan_node->thrift_olap_scan_node().columns_desc);
+            auto columns_desc_copy = _scan_node->thrift_olap_scan_node().columns_desc;
+            Status preprocess_status = preprocess_default_expr_for_tcolumns(columns_desc_copy);
+            if (!preprocess_status.ok()) {
+                LOG(WARNING) << "Failed to preprocess default_expr in olap_chunk_source: "
+                             << preprocess_status.to_string();
+            }
+            _tablet_schema = TabletSchema::copy(*_tablet->tablet_schema(), columns_desc_copy);
         } else {
             _tablet_schema = _tablet->tablet_schema();
         }

be/src/exec/tablet_info.cpp

@@ -18,6 +18,7 @@
 #include "column/chunk.h"
 #include "exprs/expr.h"
 #include "runtime/mem_pool.h"
+#include "storage/metadata_util.h"
 #include "storage/tablet_schema.h"
 #include "types/constexpr.h"
 #include "util/string_parser.hpp"
@@ -169,7 +170,15 @@ Status OlapTableSchemaParam::init(const TOlapTableSchemaParam& tschema, RuntimeS
 
         if (t_index.__isset.column_param) {
             auto col_param = _obj_pool.add(new OlapTableColumnParam());
-            for (auto& tcolumn_desc : t_index.column_param.columns) {
+            std::vector<TColumn> columns_copy = t_index.column_param.columns;
+            Status preprocess_status = preprocess_default_expr_for_tcolumns(columns_copy);
+            if (!preprocess_status.ok()) {
+                LOG(WARNING) << "Failed to preprocess default_expr in OlapTableSchemaParam::init: "
+                             << preprocess_status.to_string();
+                columns_copy = t_index.column_param.columns;
+            }
+
+            for (auto& tcolumn_desc : columns_copy) {
                 TabletColumn* tc = _obj_pool.add(new TabletColumn());
                 tc->init_from_thrift(tcolumn_desc);
                 col_param->columns.emplace_back(tc);

be/src/exprs/cast_expr.h

@@ -308,7 +308,6 @@ struct CastToString {
 
 StatusOr<ColumnPtr> cast_nested_to_json(const ColumnPtr& column, bool allow_throw_exception);
 
-// cast column[idx] to coresponding json type.
-StatusOr<std::string> cast_type_to_json_str(const ColumnPtr& column, int idx);
+StatusOr<std::string> cast_type_to_json_str(const ColumnPtr& column, int idx, bool unindexed_struct = false);
 
 } // namespace starrocks

be/src/exprs/cast_expr_json.cpp

@@ -16,7 +16,6 @@
 
 #include "column/array_column.h"
 #include "column/column_builder.h"
-#include "column/column_viewer.h"
 #include "column/column_visitor_adapter.h"
 #include "column/json_column.h"
 #include "column/map_column.h"
@@ -37,11 +36,16 @@ constexpr bool is_type_complete_v<T, std::void_t<decltype(sizeof(T))>> = true;
 // NOTE: cast in rowwise is not efficent but intuitive
 class CastColumnItemVisitor final : public ColumnVisitorAdapter<CastColumnItemVisitor> {
 public:
-    CastColumnItemVisitor(int row, const std::string& field_name, vpack::Builder* builder)
-            : ColumnVisitorAdapter(this), _row(row), _field_name(field_name), _builder(builder) {}
-
-    static Status cast_datum_to_json(const ColumnPtr& col, int row, const std::string& name, vpack::Builder* builder) {
-        CastColumnItemVisitor visitor(row, name, builder);
+    CastColumnItemVisitor(int row, const std::string& field_name, vpack::Builder* builder, bool unindexed_struct)
+            : ColumnVisitorAdapter(this),
+              _row(row),
+              _field_name(field_name),
+              _builder(builder),
+              _unindexed_struct(unindexed_struct) {}
+
+    static Status cast_datum_to_json(const ColumnPtr& col, int row, const std::string& name, vpack::Builder* builder,
+                                     bool unindexed_struct = false) {
+        CastColumnItemVisitor visitor(row, name, builder, unindexed_struct);
         try {
             return col->accept(&visitor);
         } catch (const arangodb::velocypack::Exception& e) {
@@ -111,17 +115,19 @@ class CastColumnItemVisitor final : public ColumnVisitorAdapter<CastColumnItemVi
     }
 
     Status do_visit(const StructColumn& col) {
+        // Use indexed or unindexed object based on _unindexed_struct flag
+        // unindexed=true preserves field insertion order (crucial for default values)
         if (_field_name.empty()) {
-            _builder->openObject();
+            _builder->openObject(_unindexed_struct);
         } else {
-            _builder->add(_field_name, vpack::Value(vpack::ValueType::Object));
+            _builder->add(_field_name, vpack::Value(vpack::ValueType::Object, _unindexed_struct));
         }
         const auto& names = col.field_names();
         const auto columns = col.fields();
         for (int i = 0; i < columns.size(); i++) {
             auto name = names.size() > i ? names[i] : fmt::format("k{}", i);
             auto& field_column = columns[i];
-            RETURN_IF_ERROR(cast_datum_to_json(field_column, _row, name, _builder));
+            RETURN_IF_ERROR(cast_datum_to_json(field_column, _row, name, _builder, _unindexed_struct));
         }
         if (!_builder->isClosed()) {
             _builder->close();
@@ -132,9 +138,9 @@ class CastColumnItemVisitor final : public ColumnVisitorAdapter<CastColumnItemVi
 
     Status do_visit(const MapColumn& col) {
         if (_field_name.empty()) {
-            _builder->openObject();
+            _builder->openObject(_unindexed_struct);
         } else {
-            _builder->add(_field_name, vpack::Value(vpack::ValueType::Object));
+            _builder->add(_field_name, vpack::Value(vpack::ValueType::Object, _unindexed_struct));
         }
         auto [map_start, map_size] = col.get_map_offset_size(_row);
         const auto& val_col = col.values_column();
@@ -165,7 +171,7 @@ class CastColumnItemVisitor final : public ColumnVisitorAdapter<CastColumnItemVi
                 continue;
             }
             // VLOG(2) << "map key " << i << ": " << key_col->debug_item(i) << " , name=" << name;
-            RETURN_IF_ERROR(cast_datum_to_json(val_col, i, name, _builder));
+            RETURN_IF_ERROR(cast_datum_to_json(val_col, i, name, _builder, _unindexed_struct));
         }
 
         if (!_builder->isClosed()) {
@@ -184,7 +190,7 @@ class CastColumnItemVisitor final : public ColumnVisitorAdapter<CastColumnItemVi
         auto [offset, size] = col.get_element_offset_size(_row);
         const auto& elements = col.elements_column();
         for (int i = offset; i < offset + size; i++) {
-            RETURN_IF_ERROR(cast_datum_to_json(elements, i, "", _builder));
+            RETURN_IF_ERROR(cast_datum_to_json(elements, i, "", _builder, _unindexed_struct));
         }
 
         if (!_builder->isClosed()) {
@@ -198,7 +204,7 @@ class CastColumnItemVisitor final : public ColumnVisitorAdapter<CastColumnItemVi
         if (col.is_null(_row)) {
             _add_element(vpack::ValueType::Null);
         } else {
-            RETURN_IF_ERROR(cast_datum_to_json(col.data_column(), _row, _field_name, _builder));
+            RETURN_IF_ERROR(cast_datum_to_json(col.data_column(), _row, _field_name, _builder, _unindexed_struct));
         }
         return {};
     }
@@ -219,6 +225,7 @@ class CastColumnItemVisitor final : public ColumnVisitorAdapter<CastColumnItemVi
     int _row;
     const std::string& _field_name;
     vpack::Builder* _builder;
+    bool _unindexed_struct;
 };
 
 // Cast nested type(including struct/map/* to json)
@@ -258,13 +265,15 @@ StatusOr<ColumnPtr> cast_nested_to_json(const ColumnPtr& column, bool allow_thro
     return column_builder.build(false);
 }
 
-StatusOr<std::string> cast_type_to_json_str(const ColumnPtr& column, int idx) {
+StatusOr<std::string> cast_type_to_json_str(const ColumnPtr& column, int idx, bool unindexed_struct) {
     vpack::Builder json_builder;
     json_builder.clear();
-    RETURN_IF_ERROR(CastColumnItemVisitor::cast_datum_to_json(column, idx, "", &json_builder));
-    JsonValue json(json_builder.slice());
+    RETURN_IF_ERROR(CastColumnItemVisitor::cast_datum_to_json(column, idx, "", &json_builder, unindexed_struct));
 
-    return json.to_string();
+    auto slice = json_builder.slice();
+    JsonValue json(slice);
+    auto result = json.to_string();
+    return result;
 }
 
-} // namespace starrocks
+} // namespace starrocks

be/src/storage/lake/schema_change.cpp

@@ -336,7 +336,14 @@ Status SchemaChangeHandler::do_process_alter_tablet(const TAlterTabletReqV2& req
 
     TabletSchemaCSPtr base_schema;
     if (!request.columns.empty() && request.columns[0].col_unique_id >= 0) {
-        base_schema = TabletSchema::copy(*(base_tablet.get_schema()), request.columns);
+        auto columns_copy = request.columns;
+
+        Status preprocess_status = preprocess_default_expr_for_tcolumns(columns_copy);
+        if (!preprocess_status.ok()) {
+            LOG(WARNING) << "Failed to preprocess default_expr in Lake SchemaChange: " << preprocess_status.to_string();
+        }
+
+        base_schema = TabletSchema::copy(*(base_tablet.get_schema()), columns_copy);
     } else {
         base_schema = base_tablet.get_schema();
     }

be/src/storage/metadata_util.cpp

@@ -15,10 +15,20 @@
 #include "storage/metadata_util.h"
 
 #include <boost/algorithm/string.hpp>
+#include <chrono>
+#include <ctime>
 
+#include "column/column_helper.h"
 #include "common/config.h"
+#include "common/object_pool.h"
+#include "exprs/cast_expr.h"
+#include "exprs/expr.h"
+#include "exprs/expr_context.h"
 #include "gen_cpp/AgentService_types.h"
+#include "gen_cpp/Types_types.h"
 #include "gutil/strings/substitute.h"
+#include "runtime/exec_env.h"
+#include "runtime/runtime_state.h"
 #include "storage/aggregate_type.h"
 #include "storage/olap_common.h"
 #include "storage/tablet_schema.h"
@@ -418,4 +428,88 @@ Status convert_t_schema_to_pb_schema(const TTabletSchema& t_schema, TabletSchema
     return convert_t_schema_to_pb_schema(t_schema, compression_type, out_schema);
 }
 
+// Helper function to create a minimal RuntimeState for constant expression evaluation
+static std::unique_ptr<RuntimeState> create_temp_runtime_state() {
+    TUniqueId dummy_query_id;
+    dummy_query_id.hi = 0;
+    dummy_query_id.lo = 0;
+
+    TQueryOptions query_options;
+    TQueryGlobals query_globals;
+    auto now = std::chrono::system_clock::now();
+    auto now_time_t = std::chrono::system_clock::to_time_t(now);
+    auto now_ms = std::chrono::duration_cast<std::chrono::milliseconds>(now.time_since_epoch()).count();
+
+    std::tm tm_buf;
+    localtime_r(&now_time_t, &tm_buf);
+    char time_str[64];
+    strftime(time_str, sizeof(time_str), "%Y-%m-%d %H:%M:%S", &tm_buf);
+
+    query_globals.now_string = time_str;
+    query_globals.timestamp_ms = now_ms;
+    query_globals.time_zone = "UTC";
+
+    auto state = std::make_unique<RuntimeState>(dummy_query_id, query_options, query_globals, ExecEnv::GetInstance());
+    state->init_instance_mem_tracker();
+
+    return state;
+}
+
+StatusOr<std::string> convert_default_expr_to_json_string(const TExpr& t_expr) {
+    auto state = create_temp_runtime_state();
+    ObjectPool pool;
+
+    ExprContext* ctx = nullptr;
+    RETURN_IF_ERROR(Expr::create_expr_tree(&pool, t_expr, &ctx, state.get()));
+
+    if (ctx == nullptr || ctx->root() == nullptr) {
+        return Status::InternalError("Failed to create expression tree from TExpr");
+    }
+
+    RETURN_IF_ERROR(ctx->prepare(state.get()));
+    RETURN_IF_ERROR(ctx->open(state.get()));
+
+    ColumnPtr column;
+    auto eval_result = ctx->root()->evaluate_const(ctx);
+    if (!eval_result.ok()) {
+        ctx->close(state.get());
+        return eval_result.status();
+    }
+    column = eval_result.value();
+
+    if (column == nullptr || column->size() == 0) {
+        ctx->close(state.get());
+        return Status::InternalError("Failed to evaluate default expression: empty result");
+    }
+
+    if (column->is_constant()) {
+        auto const_col = down_cast<const ConstColumn*>(column.get());
+        column = const_col->data_column()->clone();
+    }
+
+    DCHECK_EQ(column->size(), 1) << "Default constant expression should produce exactly one value";
+
+    ASSIGN_OR_RETURN(auto json_str, cast_type_to_json_str(column, 0, true));
+    ctx->close(state.get());
+
+    return json_str;
+}
+
+Status preprocess_default_expr_for_tcolumns(std::vector<TColumn>& columns) {
+    for (auto& column : columns) {
+        if (column.__isset.default_expr) {
+            auto result = convert_default_expr_to_json_string(column.default_expr);
+            if (result.ok()) {
+                column.default_value = result.value();
+                column.__isset.default_value = true;
+            } else {
+                LOG(ERROR) << "Failed to convert default_expr to JSON String for column '" << column.column_name
+                           << "': " << result.status().to_string();
+            }
+        }
+    }
+
+    return Status::OK();
+}
+
 } // namespace starrocks

be/src/storage/metadata_util.h

@@ -22,7 +22,6 @@
 #include "common/status.h"
 #include "gen_cpp/Types_types.h"
 #include "olap_common.h"
-#include "types/logical_type.h"
 
 namespace starrocks {
 
@@ -58,4 +57,8 @@ void convert_to_new_version(TColumn* tcolumn);
 
 Status t_column_to_pb_column(int32_t unique_id, const TColumn& t_column, ColumnPB* column_pb);
 
+StatusOr<std::string> convert_default_expr_to_json_string(const TExpr& t_expr);
+
+Status preprocess_default_expr_for_tcolumns(std::vector<TColumn>& columns);
+
 } // namespace starrocks