morrySnow commented on issue #44353: URL: https://github.com/apache/doris/issues/44353#issuecomment-2513792462
table is aggregate model. when pre-aggregation mode is OFF, storage layer will merge tuples of same key into one tuple before return data for execution layer. when pre-aggregation mode is ON, storage will do nothing. for example, we have a aggreagate model table t1 with ``` c1 key, c2 int sum ``` and then insert data into t1 with ``` insert into t1 values(1, 1), (1, 2) ``` when pre-aggregation mode is OFF, execution layer get ``` 1, 3 ``` but when pre-aggregation mode is ON, execution layer get ``` 1, 2 1, 1 ``` So, we set pre-aggregation to ON only when we can ensure not merging data will not leading to wrong result. Currently, we could only support the aggregation function exactly same with aggregation function in table. We will support more pattern in future. -- 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
