mrhhsg commented on code in PR #59263:
URL: https://github.com/apache/doris/pull/59263#discussion_r3319069126
##########
be/src/storage/segment/column_reader.cpp:
##########
@@ -855,6 +855,25 @@ Status
ColumnReader::new_struct_iterator(ColumnIteratorUPtr* iterator,
return Status::OK();
}
+void ColumnIterator::_convert_to_place_holder_column(MutableColumnPtr& dst,
size_t count) {
+ if (_reading_flag != ReadingFlag::SKIP_READING && _reading_mode ==
ReadingMode::PREDICATE) {
+ _has_place_holder_column = true;
+ }
+
+ if (_reading_mode != ReadingMode::LAZY) {
+ dst->insert_many_defaults(count);
+ }
+}
+
+void ColumnIterator::_recovery_from_place_holder_column(MutableColumnPtr& dst)
{
+ if (_reading_mode == ReadingMode::LAZY) {
Review Comment:
已改成单个 `if (_reading_mode == ReadingMode::LAZY && _has_place_holder_column)`
判断，避免嵌套 if。
##########
be/src/storage/segment/column_reader.cpp:
##########
@@ -882,6 +901,37 @@ Result<TColumnAccessPaths>
ColumnIterator::_get_sub_access_paths(
return sub_access_paths;
}
+Result<TColumnAccessPaths> ColumnIterator::_process_sub_access_paths(
+ const TColumnAccessPaths& access_paths, const bool is_predicate) {
+ TColumnAccessPaths sub_access_paths = access_paths;
Review Comment:
已把 `_get_sub_access_paths` 改成按值传参，直接在参数副本上处理，避免函数内再额外 copy。
##########
be/src/storage/segment/column_reader.h:
##########
@@ -424,18 +426,82 @@ class ColumnIterator {
bool read_offset_only() const { return _read_mode ==
ReadMode::OFFSET_ONLY; }
bool read_null_map_only() const { return _read_mode ==
ReadMode::NULL_MAP_ONLY; }
+ enum class ReadingMode : int {
+ NORMAL, // default mode
+ PREDICATE,
+ LAZY
+ };
+
+ virtual void set_reading_mode(ReadingMode mode) {
+ _reading_mode = mode;
+ if (mode == ReadingMode::PREDICATE) {
+ _has_place_holder_column = false;
+ }
+ }
+
+ virtual bool need_to_read() const {
+ switch (_reading_mode) {
+ case ReadingMode::NORMAL:
+ return _reading_flag != ReadingFlag::SKIP_READING;
+ case ReadingMode::PREDICATE:
+ return _reading_flag == ReadingFlag::READING_FOR_PREDICATE;
+ case ReadingMode::LAZY:
+ return _reading_flag == ReadingFlag::NEED_TO_READ;
+ default:
+ return false;
+ }
+ }
+
+ // Whether need to read meta columns, such as null map column, offset
column.
+ bool need_to_read_meta_columns() const {
+ if (_reading_flag == ReadingFlag::SKIP_READING) {
+ return false;
+ }
+ switch (_reading_mode) {
+ case ReadingMode::NORMAL:
+ case ReadingMode::PREDICATE:
+ return true;
+ case ReadingMode::LAZY:
+ return _reading_flag != ReadingFlag::READING_FOR_PREDICATE;
+ }
+ return false;
+ }
+
+ virtual void finalize_lazy_mode(MutableColumnPtr& dst) {
+ _recovery_from_place_holder_column(dst);
+ }
+
+ virtual void set_reading_flag_recursively(ReadingFlag flag) {
set_reading_flag(flag); }
Review Comment:
这里保留递归命名并补了注释：`set_reading_flag()` 只改当前
iterator，`set_reading_flag_recursively()` 用于一次性设置整棵子树；reading mode
目前只有递归设置的使用场景，所以没有再增加一个不使用的非递归同名接口。
##########
be/src/storage/segment/column_reader.h:
##########
@@ -424,18 +426,82 @@ class ColumnIterator {
bool read_offset_only() const { return _read_mode ==
ReadMode::OFFSET_ONLY; }
bool read_null_map_only() const { return _read_mode ==
ReadMode::NULL_MAP_ONLY; }
+ enum class ReadingMode : int {
+ NORMAL, // default mode
+ PREDICATE,
+ LAZY
+ };
+
+ virtual void set_reading_mode(ReadingMode mode) {
+ _reading_mode = mode;
+ if (mode == ReadingMode::PREDICATE) {
+ _has_place_holder_column = false;
+ }
+ }
+
+ virtual bool need_to_read() const {
+ switch (_reading_mode) {
+ case ReadingMode::NORMAL:
+ return _reading_flag != ReadingFlag::SKIP_READING;
+ case ReadingMode::PREDICATE:
+ return _reading_flag == ReadingFlag::READING_FOR_PREDICATE;
+ case ReadingMode::LAZY:
+ return _reading_flag == ReadingFlag::NEED_TO_READ;
+ default:
+ return false;
+ }
+ }
+
+ // Whether need to read meta columns, such as null map column, offset
column.
+ bool need_to_read_meta_columns() const {
+ if (_reading_flag == ReadingFlag::SKIP_READING) {
+ return false;
+ }
+ switch (_reading_mode) {
+ case ReadingMode::NORMAL:
+ case ReadingMode::PREDICATE:
+ return true;
+ case ReadingMode::LAZY:
+ return _reading_flag != ReadingFlag::READING_FOR_PREDICATE;
+ }
+ return false;
+ }
+
+ virtual void finalize_lazy_mode(MutableColumnPtr& dst) {
+ _recovery_from_place_holder_column(dst);
+ }
+
+ virtual void set_reading_flag_recursively(ReadingFlag flag) {
set_reading_flag(flag); }
+
+ // Whether this iterator or any nested iterator has data that must be
materialized
+ // in lazy mode. Predicate-only and meta-only branches are read before
filtering and
+ // must not be re-read in the lazy phase.
+ virtual bool has_lazy_read_target() const { return _reading_flag ==
ReadingFlag::NEED_TO_READ; }
+
+ bool is_pruned() const { return _pruned; }
Review Comment:
已删除冗余的 `is_pruned()` 条件，并在代码注释里说明：`reading_flag() == READING_FOR_PREDICATE
&& has_lazy_read_target()` 已经隐含发生过 nested-column pruning。
##########
be/src/storage/segment/column_reader.h:
##########
@@ -424,18 +426,81 @@ class ColumnIterator {
bool read_offset_only() const { return _read_mode ==
ReadMode::OFFSET_ONLY; }
bool read_null_map_only() const { return _read_mode ==
ReadMode::NULL_MAP_ONLY; }
+ enum class ReadingMode : int {
+ NORMAL, // default mode
+ PREDICATE,
+ LAZY
+ };
+
+ virtual void set_reading_mode(ReadingMode mode) {
+ _reading_mode = mode;
+ if (mode == ReadingMode::PREDICATE) {
+ _has_place_holder_column = false;
+ }
+ }
+
+ virtual bool need_to_read() const {
+ switch (_reading_mode) {
+ case ReadingMode::NORMAL:
+ return _reading_flag != ReadingFlag::SKIP_READING;
+ case ReadingMode::PREDICATE:
+ return _reading_flag == ReadingFlag::READING_FOR_PREDICATE;
+ case ReadingMode::LAZY:
+ return _reading_flag == ReadingFlag::NEED_TO_READ;
+ default:
+ return false;
+ }
+ }
+
+ // Whether need to read meta columns, such as null map column, offset
column.
+ bool need_to_read_meta_columns() const {
+ if (_reading_flag == ReadingFlag::SKIP_READING) {
Review Comment:
已改为 `return ColumnIterator::need_to_read();`。这里是刻意调用基类实现，避免走
Map/Struct/Array 在 LAZY 模式下包含 child target 的 override 逻辑；meta columns 是否追加只应由当前
iterator 自身的 reading flag/mode 决定。
##########
be/src/storage/segment/column_reader.cpp:
##########
@@ -855,14 +855,34 @@ Status
ColumnReader::new_struct_iterator(ColumnIteratorUPtr* iterator,
return Status::OK();
}
+void ColumnIterator::_convert_to_place_holder_column(MutableColumnPtr& dst,
size_t count) {
+ if (_reading_mode == ReadingMode::LAZY) {
+ return;
+ } else if (_reading_flag != ReadingFlag::SKIP_READING &&
Review Comment:
已将 placeholder 场景收敛为 `_reading_flag ==
ReadingFlag::NEED_TO_READ`，并补了注释说明：只有非 predicate、但 lazy 阶段还需要物化的列，才会在 predicate
phase 插入 placeholder；`READING_FOR_PREDICATE` 正常读取，`SKIP/NORMAL` 不参与 lazy
materialization。
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