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• rpl_semi_sync_master_wait_for_slave_count 

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The number of replica acknowledgments the source must receive per transaction before proceeding. By default rpl_semi_sync_master_wait_for_slave_count  is 1 , meaning that semisynchronous replication proceeds after receiving a single replica acknowledgment. Performance is best for small values of this variable. 

For example, if rpl_semi_sync_master_wait_for_slave_count  is 2 , then 2 replicas must acknowledge receipt of the transaction before the timeout period configured by rpl_semi_sync_master_timeout  for semisynchronous replication to proceed. If fewer replicas acknowledge receipt of the transaction during the timeout period, the source reverts to normal replication. 

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## Note 

This behavior also depends on rpl_semi_sync_master_wait_no_slave 

This variable is available only if the source-side semisynchronous replication plugin is installed. 

• rpl_semi_sync_master_wait_no_slave 

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Controls whether the source waits for the timeout period configured by rpl_semi_sync_master_timeout  to expire, even if the replica count drops to less than the number of replicas configured by rpl_semi_sync_master_wait_for_slave_count  during the timeout period. 

When the value of rpl_semi_sync_master_wait_no_slave  is ON  (the default), it is permissible for the replica count to drop to less than rpl_semi_sync_master_wait_for_slave_count  during 

