Description:
The --binlog_row_events_max_size option is used to decide the breaking point when a RBR event should be flushed to the binary log. In addition, to prevent excessive allocation *calls*, the value is used to allocate an appropriate buffer immediately. The default value of the option is 1024.
Suppose that the user sets a very large value, say 256MB, in an attempt to send as many rows as possible in one event. Then the ``malloc()`` used internally will allocate an excessive amount of
memory, when the normal case is to use a much smaller amount.
How to repeat:
Call mysqld with --binlog_row_events_max_size=4000000000 and see what happens.
Suggested fix:
Allocate a smaller portion initially, and double the amount of memory
whenever more is needed. To prevent an excessive number of calls to
``malloc()``, the memory does not need to be allocated each time a RBR
event is constructed, but rather a buffer could be reused.
The problems with this solution are:
- If a really large RBR event is allocated, the buffer will grow to a
large amount and take up memory in the server. If these big chunks
are rare, the server will keep a very large buffer allocated
unnecessarily.
