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16.4.1.13. Replication and Fractional Seconds Support

MySQL 5.7 permits fractional seconds for TIME, DATETIME, and TIMESTAMP values, with up to microseconds (6 digits) precision. See Section 11.3.6, "Fractional Seconds in Time Values".

There may be problems replicating from a master server that understands fractional seconds to an older slave (MySQL 5.6.3 and earlier) that does not: