The only change is a change of the version number.
In MySQL 5.6.46, the copyright comments in a number of files were changed
in mysql/mysql-server@f1a006ece7
but there was no functional change to InnoDB code.
This was also reflected by XtraDB. We are not changing the copyright
comments in MariaDB Server for now.
Between MySQL 5.6.46 and 5.6.47, InnoDB was not changed at all.
Actually, we had forgotten to update the InnoDB version number to
5.6.46. With this change, we are updating InnoDB
from 5.6.45 to 5.6.47 and XtraDB from 5.6.45-86.1 to 5.6.46-86.2.
WL#6326 in MariaDB 10.2.2 introduced a potential hang on purge or rollback
when an index tree is being shrunk by multiple levels.
This fix is based on
mysql/mysql-server@f2c5852630
with the main difference that our version of the test case uses
DEBUG_SYNC instrumentation on ROLLBACK, not on purge.
btr_cur_will_modify_tree(): Simplify the check further.
This is the actual bug fix.
row_undo_mod_remove_clust_low(), row_undo_mod_clust(): Add DEBUG_SYNC
instrumentation for the test case.
The long semaphore wait appeared to be the caused by the following
pattern in the MTR test:
```
SET DEBUG_SYNC = "now SIGNAL wsrep_after_certification_continue";
SET DEBUG_SYNC = "now SIGNAL signal.wsrep_apply_cb;
```
Raising two signals, one right after another, caused one signal to
overwrite the other, before the signal was consumed by the thread.
This caused one thread to be stuck until the debug sync point would
timeout.
A certification failure followed by a clean shutdown would cause an
inconsistency between the sequence number stored in innodb and the
sequence number stored in provider.
This happened both in the case of local certification failure, and in
the case where dummy writeset is applied.
The fix consists of:
- updating wsrep position after dummy writeset is delivered in
`Wsrep_high_priority_service::log_dummy_write_set()`
- updating wsrep position while releasing commit order in wsrep-lib
side
Added two tests which stress the situation where a server is shutdown
after a certification failure.
Analysis:
========
'max_binlog_cache_size' is configured and a huge transaction is executed. When
the transaction specific events size exceeds 'max_binlog_cache_size' the event
cannot be written to the binary log cache and cache write error is raised.
Upon cache write error the statement is rolled back and the transaction cache
should be truncated to a previous statement specific position. The truncate
operation should reset the cache to earlier valid positions and flush the new
changes. Even though the flush is successful the cache write error is still in
marked state. The truncate code interprets the cache write error as cache flush
failure and returns abruptly without modifying the write cache parameters.
Hence cache is in a invalid state. When a COMMIT statement is executed in this
session it tries to flush the contents of transaction cache to binary log.
Since cache has partial events the cache write operation will report
'writer.remains' assert.
Fix:
===
Binlog truncate function resets the cache to a specified size. As a first step
of truncation, clear the cache write error flag that was raised during earlier
execution. With this new errors that surface during cache truncation can be
clearly identified.
MDEV-18046: Assortment of crashes, assertion failures and ASAN errors in mysql_show_binlog_events
Problem:
========
SHOW BINLOG EVENTS FROM <pos> reports following assert when ASAN is enabled.
uint32 binlog_get_uncompress_len(const char*):
Assertion `(buf[0] & 0xe0) == 0x80' failed
Fix:
===
**Part11: Converted debug assert to error handler code**
Problem:
========
SHOW BINLOG EVENTS FROM <pos> causes a variety of failures, some of which are
listed below. It is not a race condition issue, but there is some
non-determinism in it.
Analysis:
========
"show binlog events from <pos>" code considers the user given position as a
valid event start position. The code starts reading data from this event start
position onwards and tries to map it to a set of known events. Each event has
a specific event structure and asserts have been added to ensure that read
event data satisfies the event specific requirements. When a random position
is supplied to "show binlog events command" the event structure specific
checks will fail and they result in assert.
Fix:
====
The fix is split into different parts. Each part addresses either an ASAN
issue or an assert/crash.
**Part1: Checksum based position validation when checksum is enabled**
Using checksum validate the very first event read at the user specified
position. If there is a checksum mismatch report an appropriate error for the
invalid event.
The test encryption.innodb-redo-badkey will by design cause access
to pages that appear corrupted (due to incorrect encryption key).
Let us disable the page dumps by requiring the test to be run on
a debug server. Page dumps on debug builds were already disabled
in MDEV-19766.
By default (innodb_strict_mode=ON), InnoDB attempts to guarantee
at DDL time that any INSERT to the table can succeed.
MDEV-19292 recently revised the "row size too large" check in InnoDB.
The check still is somewhat inaccurate;
that should be addressed in MDEV-20194.
Note: If a table contains multiple long string columns so that each column
is part of a column prefix index, then an UPDATE that attempts to modify
all those columns at once may fail, because the undo log record might
not fit in a single undo log page (of innodb_page_size). In the worst case,
the undo log record would grow by about 3KiB of for each updated column.
The DDL-time check (since the InnoDB Plugin for MySQL 5.1) is optional
in the sense that when the maximum B-tree record size or undo log
record size would be exceeded, the DML operation will fail and the
transaction will be properly rolled back.
create_table_info_t::row_size_is_acceptable(): Add the parameter
'bool strict' so that innodb_strict_mode=ON can be overridden during
TRUNCATE, OPTIMIZE and ALTER TABLE...FORCE (when the storage format
is not changing).
create_table_info_t::create_table(): Perform a sloppy check for
TRUNCATE TABLE (create_fk=false).
prepare_inplace_alter_table_dict(): Perform a sloppy check for
simple operations.
trx_is_strict(): Remove. The function became unused in
commit 98694ab0cb (MDEV-20949).
