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MDEV-22242 B-trees can become extremely skewed

The test innodb.innodb_wl6326 that had been disabled in 10.4 due to
MDEV-21535 is failing on 10.5 due to a different reason: the removal
of the MLOG_COMP_END_COPY_CREATED operations in MDEV-12353
commit 276f996af9 caused PAGE_LAST_INSERT
to be set to something nonzero by the function page_copy_rec_list_end().

This in turn would cause btr_page_get_split_rec_to_right() to behave
differently: we would not attempt to split the page at all, but simply
insert the new record into the new, empty, right leaf page.

Even though the change reduced the sizes of some tables, it is better
to aim for balanced trees.

page_copy_rec_list_end(), PageBulk::finishPage():
Preserve PAGE_LAST_INSERT, PAGE_N_DIRECTION, PAGE_DIRECTION.

PageBulk::finish(): Move some common code from PageBulk::finishPage().
This commit is contained in:
Marko Mäkelä
2020-04-14 18:43:03 +03:00
parent 87a7968c23
commit 2f7d91bb6c
20 changed files with 272 additions and 282 deletions

View File

@ -14,7 +14,7 @@ SELECT NULL, REPEAT('b', 64), REPEAT('c', 256) FROM seq_1_to_16382;
SELECT COUNT(*) FROM information_schema.innodb_buffer_page_lru
WHERE table_name = '`test`.`ib_bp_test`';
COUNT(*)
594
596
SET GLOBAL innodb_buffer_pool_dump_now = ON;
SET GLOBAL innodb_fast_shutdown=0;
# restart
@ -32,7 +32,7 @@ Buffer pool(s) load completed at TIMESTAMP_NOW
SELECT COUNT(*) FROM information_schema.innodb_buffer_page_lru
WHERE table_name = '`test`.`ib_bp_test`';
COUNT(*)
594
596
call mtr.add_suppression("InnoDB: Error parsing");
SET GLOBAL innodb_buffer_pool_load_now = ON;
# Re-write some valid pages to the dump file, make sure the space