Warning | 1292：Truncated incorrect binlog_cache_size value:
官方文档上关于binlog_cache_size的描述如下：
binlog_cache_size
| Command-Line Format | --binlog_cache_size=# | ||
| System Variable | Name | binlog_cache_size | |
| Variable Scope | Global | ||
| Dynamic Variable | Yes | ||
| Permitted Values (32-bit platforms) | Type | integer | |
| Default | 32768 | ||
| Min Value | 4096 | ||
| Max Value | 4294967295 | ||
| Permitted Values (64-bit platforms) | Type | integer | |
| Default | 32768 | ||
| Min Value | 4096 | ||
| Max Value | 18446744073709551615 | ||
The size of the cache to hold changes to the binary log during a transaction. A binary log cache is allocated for each client if the server supports any transactional storage engines and if the server has the binary log enabled (--log-bin option). If you often use large transactions, you can increase this cache size to get better performance. The Binlog_cache_use and Binlog_cache_disk_use status variables can be useful for tuning the size of this variable. See Section 6.4.4, “The Binary Log”.
binlog_cache_size sets the size for the transaction cache only; the size of the statement cache is governed by the binlog_stmt_cache_size system variable.
实验：
mysql> select 4096/1024
-> ;
+-----------+
| 4096/1024 |
+-----------+
| 4.0000 |
+-----------+
1 row in set (0.00 sec)
mysql> set global binlog_cache_size=1024*4;
Query OK, 0 rows affected (0.00 sec)
mysql> set global binlog_cache_size=1024*8;
Query OK, 0 rows affected (0.00 sec)
mysql> set global binlog_cache_size=1024*4*2;
Query OK, 0 rows affected (0.00 sec)
mysql> set global binlog_cache_size=1024*4*3;
Query OK, 0 rows affected (0.00 sec)
mysql> set global binlog_cache_size=1024*5;
Query OK, 0 rows affected, 1 warning (0.00 sec)
mysql> show warnings;
+---------+------+-----------------------------------------------------+
| Level | Code | Message |
+---------+------+-----------------------------------------------------+
| Warning | 1292 | Truncated incorrect binlog_cache_size value: '5120' |
+---------+------+-----------------------------------------------------+
1 row in set (0.00 sec)
mysql> set global binlog_cache_size=1024*6;
Query OK, 0 rows affected, 1 warning (0.00 sec)
mysql> set global binlog_cache_size=1024*7;
Query OK, 0 rows affected, 1 warning (0.00 sec)
mysql> set global binlog_cache_size=1024*9;
Query OK, 0 rows affected, 1 warning (0.00 sec)
mysql> set global binlog_cache_size=1024*10;
Query OK, 0 rows affected, 1 warning (0.00 sec)
mysql> show variables like 'binlog_cache_size';
+-------------------+-------+
| Variable_name | Value |
+-------------------+-------+
| binlog_cache_size | 8192 |
+-------------------+-------+
1 row in set (0.00 sec)
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