yiguolei commented on code in PR #57702:
URL: https://github.com/apache/doris/pull/57702#discussion_r2544267001
##########
be/src/olap/rowset/segment_v2/segment.cpp:
##########
@@ -681,15 +692,39 @@ Status
Segment::_create_column_meta_once(OlapReaderStatistics* stats) {
}
Status Segment::_create_column_meta(const SegmentFooterPB& footer) {
- // unique_id -> idx in footer.columns()
- uint32_t ordinal = 0;
- for (const auto& column_meta : footer.columns()) {
- // no need to create column reader for variant's subcolumn
- if (column_meta.unique_id() == -1) {
- ordinal++;
- continue;
+ // Build uid -> col_id mapping used to locate per-column meta.
+ // Priority:
+ // 1) uid2colid blob in footer.file_meta_datas (external meta mode, raw
uid array)
+ // 2) fallback: scan footer.columns() (old or mixed format)
+ // 3) both missing -> treat as no columns resolvable in this segment
(return NOT_FOUND on lookup)
+ _column_uid_to_footer_ordinal.clear();
+ // Decide path by footer version: V3 and above uses externalized
ColumnMeta region
+ const bool use_external_meta = footer.version() >=
kSegmentFooterVersionV3_ExtColMeta;
+ // 1) Prefer uid->col_id blob (external meta mode). If corrupted or
missing, fall back.
+ ExternalColMetaUtil::ExternalMetaPointers ptrs;
+ bool loaded = false;
+ if (use_external_meta) {
+ loaded = ExternalColMetaUtil::parse_external_meta_pointers(footer,
&ptrs) &&
+ ExternalColMetaUtil::parse_uid_to_colid_map(footer, ptrs,
+
&_column_uid_to_footer_ordinal);
+ }
+ // 2) Fallback: inline footer columns (old or mixed format)
+ if (!loaded && footer.columns_size() > 0) {
+ uint32_t ordinal = 0;
+ for (const auto& column_meta : footer.columns()) {
+ if (column_meta.unique_id() == -1) {
+ ordinal++;
+ continue;
+ }
+ _column_uid_to_footer_ordinal.try_emplace(column_meta.unique_id(),
ordinal++);
}
- _column_uid_to_footer_ordinal.try_emplace(column_meta.unique_id(),
ordinal++);
+ loaded = true;
+ }
+ // 3) If still not loaded, warn once to aid troubleshooting (damaged
mapping and empty inline columns).
+ if (!loaded) {
+ LOG(WARNING) << "segment external meta mapping missing or corrupted
and no inline columns; "
+ "uid->col_id cannot be resolved. path="
Review Comment:
此时，为什么不直接报错？
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