[GitHub] [doris] adonis0147 commented on a diff in pull request #10386: [improvement]Use std::iota to set values of _block_rowids in SegmentIterator::_read_columns_by_index

[GitBox <gi...@apache.org>]

adonis0147 commented on code in PR #10386:
URL: https://github.com/apache/doris/pull/10386#discussion_r905863804


##########
be/src/olap/rowset/segment_v2/segment_iterator.cpp:
##########
@@ -872,9 +872,11 @@ Status SegmentIterator::_read_columns_by_index(uint32_t nrows_read_limit, uint32
                 _read_columns(_first_read_column_ids, _current_return_columns, rows_to_read));
         _cur_rowid += rows_to_read;
         if (set_block_rowid) {
-            for (uint32_t rid = range_from; rid < range_to; rid++) {
-                _block_rowids[nrows_read++] = rid;
-            }
+            // Here use std::iota is better performance than for-loop, maybe for-loop is not vectorized

Review Comment:
   This comment is wrong, compiler vectorizes both loops.



-- 
This is an automated message from the Apache Git Service.
To respond to the message, please log on to GitHub and use the
URL above to go to the specific comment.

To unsubscribe, e-mail: commits-unsubscribe@doris.apache.org

For queries about this service, please contact Infrastructure at:
users@infra.apache.org


---------------------------------------------------------------------
To unsubscribe, e-mail: commits-unsubscribe@doris.apache.org
For additional commands, e-mail: commits-help@doris.apache.org