MySQL 8.0 Reference Manual Including MySQL NDB Cluster 8.0

8.14.5 Replication I/O Thread States

The following list shows the most common states you see in the State column for a replication I/O thread on a replica server. This state also appears in the Replica_IO_State column displayed by SHOW REPLICA | SLAVE STATUS, so you can get a good view of what is happening by using that statement.