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MDEV-22242 B-trees can become extremely skewed

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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
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3
mysql-test/suite/innodb/r/innodb-change-buffer-recovery.result
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@@ -13,7 +13,6 @@ c INT,
INDEX(b))
ENGINE=InnoDB STATS_PERSISTENT=0;
SET GLOBAL innodb_change_buffering_debug = 1;
SET GLOBAL innodb_limit_optimistic_insert_debug=700;
INSERT INTO t1 SELECT 0,'x',1 FROM seq_1_to_8192;
BEGIN;
SELECT b FROM t1 LIMIT 3;
@@ -51,5 +50,5 @@ Table Op Msg_type Msg_text
test.t1 check status OK
SHOW ENGINE INNODB STATUS;
Type Name Status
InnoDB insert 139, delete mark 1
InnoDB insert 79, delete mark 1
DROP TABLE t1;