gaodayue commented on a change in pull request #1633: add zone map page(#1390)
URL: https://github.com/apache/incubator-doris/pull/1633#discussion_r314976304
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File path: be/src/olap/rowset/segment_v2/column_writer.cpp
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@@ -139,8 +153,19 @@ Status ColumnWriter::_append_data(const uint8_t** ptr,
size_t num_rows) {
_null_bitmap_builder->add_run(false, num_written);
}
- // TODO(zc): update statistics for this page
-
+ if (_opts.need_zone_map) {
+ for (int i = 0; i < num_written; ++i) {
+ if (!_page_min_value->is_null()
+ &&
_page_min_value->field()->compare(_page_min_value->cell_ptr(), start_ptr) > 0) {
+ _page_min_value->copy(start_ptr);
Review comment:
If values of the column are mostly in ascending or descending order, this
would lead to too many memcpy, which is very inefficient. Please leave a TODO
here, so we can investigate how to avoid value copy (especially for string) in
the future.
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