In Log_event::read_log_event(), don't use IO_CACHE::error of the relay log's
IO_CACHE to signal an error back to the caller. When reading the active
relay log, this flag is also being used by the IO thread, and setting it can
randomly cause the IO thread to wrongly detect IO error on writing and
permanently disable the relay log.
This was seen sporadically in test case rpl.rpl_from_mysql80. The read
error set by the SQL thread in the IO_CACHE would be interpreted as a
write error by the IO thread, which would cause it to throw a fatal
error and close the relay log. And this would later cause CHANGE
MASTER to try to purge a closed relay log, resulting in nullptr crash.
SQL thread is not able to parse an event read from the relay log. This
can happen like here when replicating unknown events from a MySQL master,
potentially also for other reasons.
Also fix a mistake in my_b_flush_io_cache() introduced back in 2001
(fa09f2cd7e) where my_b_flush_io_cache() could wrongly return an error set
in IO_CACHE::error, even if the flush operation itself succeeded.
Also fix another sporadic failure in rpl.rpl_from_mysql80 where the outout
of MASTER_POS_WAIT() depended on timing of SQL and IO thread.
Reviewed-by: Monty <monty@mariadb.org>
Reviewed-by: Andrei Elkin <andrei.elkin@mariadb.com>
Signed-off-by: Kristian Nielsen <knielsen@knielsen-hq.org>
MDEV-29533 Crash when MariaDB is replica of MySQL 8.0
MySQL 8.0 has added the following new events in the MySQL binary log
PARTIAL_UPDATE_ROWS_EVENT
TRANSACTION_PAYLOAD_EVENT
HEARTBEAT_LOG_EVENT_V2
- PARTIAL_UPDATE_ROWS_EVENT is used by MySQL to generate update
statements using JSON_SET, JSON_REPLACE and JSON_REMOVE to make
update of JSON columns more efficient. These events can be
disabled by setting 'binlog-row-value-options=""'
- TRANSACTION_PAYLOAD_EVENT is used by MySQL to signal that a
row event is compressed. It an be disably by setting
'binlog_transaction_compression=0'.
- HEARTBEAT_LOG_EVENT_V2 is written to the binary log many times
per seconds. It can be ignored by the server.
What this patch does:
- If PARTIAL_UPDATE_ROWS_EVENT or TRANSACTION_PAYLOAD_EVENT is found,
the server will stop with an error message of how to disable the
MySQL server to generate such events.
- HEARTBEAT_LOG_EVENT_V2 events are ignored.
- mariadb-binlog will write the name of the new events.
- mariadb-binlog will stop if PARTIAL_UPDATE_ROWS_EVENT or
TRANSACTION_PAYLOAD_EVENT is found, unless --force is given.
- Fixes a crash in mariadb-binlog if a character set unknown to
MariaDB is found. (MDEV-29533)
From Kristian Nielsen:
- Add test case for MySQL 8.0 to MariaDB replication and fixed a
a small typo in post_header_len initialization.
Reviewer: knielsen@mariadb.org
