xiaokang commented on code in PR #10694:
URL: https://github.com/apache/doris/pull/10694#discussion_r937402867
##########
be/src/olap/rowset/segment_v2/segment_iterator.cpp:
##########
@@ -915,7 +959,8 @@ Status SegmentIterator::_read_columns_by_index(uint32_t
nrows_read_limit, uint32
} else {
nrows_read += rows_to_read;
}
- } while (nrows_read < nrows_read_limit);
+ // if _opts.read_orderby_key_reverse is true, only read one range for
fast reverse purpose
Review Comment:
OK. It's related to the code 'reverse block row order' at the end of
SegmentIterator::next_batch.
If we read more than one range in reverse order here, such as range10 with
rows 9000 ~ 10000 and range9 with rows 8000 ~ 9000, the block will contain
non-continous ordered rows 9000 ~ 10000,8000 ~ 9000. Then the reverse block at
the end of next_batch will get rows 9000 ~ 8000,10000 ~ 9000. It's not totally
in reversed order.
--
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-unsubscr...@doris.apache.org
For queries about this service, please contact Infrastructure at:
us...@infra.apache.org
---------------------------------------------------------------------
To unsubscribe, e-mail: commits-unsubscr...@doris.apache.org
For additional commands, e-mail: commits-h...@doris.apache.org
