Expanded fast index creation inadvertently uses the fast index creation for temp tables

[Laurynas Biveinis]

MySQL has disabled fast index creation for InnoDB temp tables: http://bugs.mysql.com/bug.php?id=39833.

The Percona Server expanded fast index creation inadvertently uses it for some indexes on temporary tables (bug 999147): : when there is an already-existing secondary index on the table, it will be dropped from the new temp table and recreated after copying the data.

This is not a particularly well-tested code path (bug 999147 is one example what may go wrong). Either let's fully disable it, either test and fully enable it, in process fixing the upstream 39833.

[Laurynas Biveinis (laurynas-biveinis)]

SET SESSION expand_fast_index_creation=ON;

CREATE TEMPORARY TABLE t1 (a INT, b INT, INDEX(a));
ALTER TABLE t1 ADD INDEX (b);

[Laurynas Biveinis (laurynas-biveinis)]

This is now being tested, several 5.5-5.7 testcases and 5.7 fixes have been implemented. Considering as supported.

[Shahriyar Rzayev (rzayev-sehriyar)]

Percona now uses JIRA for bug reports so this bug report is migrated to: https://jira.percona.com/browse/PS-558