The test case for reproducing MDEV-14126 demonstrates that InnoDB can
end up with an index tree where a non-leaf page has only one child page.
The test case innodb.innodb_bug14676111 demonstrates that such pages
are sometimes unavoidable, because InnoDB does not implement any sort
of B-tree rotation.
But, there is no reason to allow a root page with only one child page.
btr_cur_node_ptr_delete(): Replaces btr_node_ptr_delete().
btr_page_get_father(): Declare globally.
btr_discard_only_page_on_level(): Declare with ATTRIBUTE_COLD.
It turns out that this function is not covered by the
innodb.innodb_bug14676111 test case after all.
btr_discard_page(): If the root page ends up having only one child
page, shrink the tree by invoking btr_lift_page_up().
The test was unnecessarily depending on InnoDB purge, which can
sometimes fail to proceed.
Let us rewrite the test to use BEGIN;INSERT;ROLLBACK to cause the
immediate removal of the desired records.
The test was unnecessarily depending on InnoDB purge, which can
sometimes fail to proceed.
Let us rewrite the test to use BEGIN;INSERT;ROLLBACK to cause the
immediate removal of the desired records.
Revert the MDEV-4396 tweak to innodb.innodb_bug14676111.
We must fix the root cause instead.
Allow gcol.innodb_virtual_purge to run on a non-debug build
(If wait_innodb_all_purged.inc is used in a non-debug test,
it will have no effect.)
Add the test innodb.index_merge_threshold from MySQL 5.7.
btr_lift_page_up() writes wrong page number (different by -1) for upper than father page.
But in almost all of the cases, the father page should be root page, no upper
pages. It is very rare path.
In addition the leaf page should not be lifted unless the father page is root.
Because the branch pages should not become the leaf pages.
rb://1336 approved by Marko Makela.
