MySQL 9.7 Release Notes
Using different server SQL mode settings on the source and the
replica may cause the same INSERT
statements to be handled differently on the source and the
replica, leading the source and replica to diverge. For best
results, you should always use the same server SQL mode on the
source and on the replica. This advice applies whether you are
using statement-based or row-based replication.
For INTERPRET_UTF8_AS_UTF8MB4,
the source records the applicable SQL mode in the binary log for
every statement logged using statement format and for every DDL
statement, regardless of the
binlog_format setting. The
replica applies the statement using the recorded mode, so
utf8 character set and collation aliases
resolve in the same way on the source and replica.
Before a source begins using
INTERPRET_UTF8_AS_UTF8MB4,
upgrade every replica to a MySQL release that recognizes the
mode. Configure the same SQL mode on all servers that may be
promoted to source. Otherwise, statements executed locally after
a takeover may interpret utf8 aliases
differently.
If you are replicating partitioned tables, using different SQL modes on the source and the replica is likely to cause issues. At a minimum, this is likely to cause the distribution of data among partitions to be different in the source's and replica's copies of a given table. It may also cause inserts into partitioned tables that succeed on the source to fail on the replica.
For more information, see Section 7.1.11, “Server SQL Modes”.