As you may have noticed by now, we are continuously improving and enhancing the experience of managing a MySQL server. Furthermore, we have also released tools, such as MySQL shell, that make advanced and distributed setups like creating, deploying, and running clusters of InnoDB instances, seamless to the end user.
Now, coming back to the server itself, some configuration options that used to be static are now dynamically settable. In addition to that, the SET PERSIST framework is a tool to effortlessly persist the modified values for dynamic system variables. This makes the configuration changes durable across server restarts. All of this adds up to deliver a great user experience to the end user.
Building on that trend, in MySQL 8.0.14, a command line option was turned into a system variable that can be read through a regular session. It can also be changed through SET PERSIST_ONLY, so that on the next server restart, it gets assigned a different value.
The new system variable is binlog-row-event-max-size and this variable tries to set a cap on the maximum size of a row-based binary log event whenver possible. As such the following feature request is now be fixed: BUG#74728. The properties of this variable are:
|
1
2
3
4
5
6
7
|
NAME: binlog_row_event_max_size VALUES: [256, ULONG_MAX] DEFAULT: 8192 SCOPE: GLOBAL REPLICATED: No DYNAMIC: No PERSIST: Yes (PERSIST_ONLY) |
More details about the work done towards converting the command line option into a system variable can be found here: WL#12385.
So now the user can actually read the value of this variable as well as configure a different value that will be set on the next server restart. Here is a sample:
|
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
|
mysql> SELECT @@global.binlog_row_event_max_size; +------------------------------------+ | @@global.binlog_row_event_max_size | +------------------------------------+ | 8192 | +------------------------------------+ 1 row in set (0,00 sec) mysql> SHOW VARIABLES LIKE 'binlog_row_event_max_size'; +---------------------------+-------+ | Variable_name | Value | +---------------------------+-------+ | binlog_row_event_max_size | 8192 | +---------------------------+-------+ 1 row in set (0,01 sec) mysql> SET @@persist_only.binlog_row_event_max_size=16384; Query OK, 0 rows affected (0,00 sec) mysql> SELECT variable_value FROM performance_schema.persisted_variables WHERE variable_name = 'binlog_row_event_max_size'; +----------------+ | variable_value | +----------------+ | 16384 | +----------------+ 1 row in set (0,00 sec) mysql> RESET PERSIST binlog_row_event_max_size; Query OK, 0 rows affected (0,00 sec) mysql> SELECT variable_value FROM performance_schema.persisted_variables WHERE variable_name = 'binlog_row_event_max_size'; Empty set (0,00 sec) |
Thanks for using MySQL. Enjoy!