11fe730ef2
When a condition was pushed from HAVING into WHERE, its fields were unwrapped in place. The pushed condition then shared field items with the SELECT list. Creating the GROUP BY temporary table later bound those items to the temporary table. With a 'Range checked for each record' plan, range analysis took the value of the outer table's field from the not yet filled temporary table. It built an impossible range, and the query returned no rows. The pushed condition is now cloned before its fields are unwrapped, so it gets its own field items. Items that cannot be cloned (e.g. subqueries) are still unwrapped in place, to keep the pushdown. Such conditions are unlikely to get a 'Range checked for each record' plan. Cloning can also fail with an error, which the pushdown did not handle properly. It modifies HAVING before all of its steps have succeeded, yet on a failure it emptied the list of pushed conditions and let the query continue, so the conditions already removed from HAVING were not checked at all. pushdown_from_having_into_where() now returns an error status, and the query errors out if the pushdown fails after it may have modified HAVING. Based on a contribution by Omar Gamal (PR #4815). Co-authored-by: OmarGamal10 <ogamal1011@gmail.com>
Code status:
ci.appveyor.com
MariaDB: The innovative open source database
MariaDB was designed as a drop-in replacement of MySQL(R) with more features, new storage engines, fewer bugs, and better performance.
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