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Handling of safe and unsafe statements. A statement is treated differently depending on whether

the statement is considered safe, and with respect to the binary logging format (that is, the current

value of binlog_format [2047]).

•    No distinction is madę in the treatment of safe and unsafe statements when the binary logging modę

is ROW.

•    If the binary logging format is MIXED, statements flagged as unsafe are logged using the row-based

format; statements regarded as safe are logged using the statement-based format.

•    If the binary logging format is STATEMENT, statements flagged as being unsafe generate a warning

to this effect. (Safe statements are logged normally.)

Each statement flagged as unsafe generates a warning. Formerly, in cases where a great many

such statements were executed on the master, this could lead to very large error log files, sometimes

even filling up an entire disk unexpectedly. To guard against this, MySQL 5.6.7 introduced a

warning suppression mechanism, which behaves as follows: Whenever the 50 most recent

ER_BINLOG_UNSAFE_STATEMENT [4232] warnings have been generated morę than 50 times in any

50-second period, warning suppression is enabled. When activated, this causes such warnings not to

be written to the error log; instead, for each 50 warnings of this type, a notę The

last warning was

repeated N times in last S seconds is written to the error log. This continues as long as the

50 most recent such warnings were issued in 50 seconds or less; once the ratę has decreased below

this threshold, the warnings are once again logged normally. Warning suppression has no effect on

howthe safety of statements for statement-based logging is determined, nor on how warnings are sent

to the Client (MySQL clients still receive one warning for each such statement).

For morę information, see Section 16.1.2, "Replication Formats".