Re: how to setup master, primary slave master and slaves

[Rick James]

M --> R --> S3,S4,S5
Having R in the middle saves virtually nothing for M. The difference (to the Master) is 1 versus 3 streams of TCP/IP stream of data. I deal with masters with more than a dozen slaves directly connected. There is no difference to the Slaves.

If you do "large" operations on the Master, the operations will be replicated to the Slaves (optionally via the Relay), then executed on the Slaves. This execution on the Slave will will "lock" whatever is needed to correctly perform the operation.

A common "large" operation is DELETE of a million rows. That is fixed by breaking it up into, say, 1000 at a time.

You mentioned INSERT. Is this one row at a time? Batch INSERT? LOAD DATA? MyISAM? InnoDB? The remedies depend on the details.

We can help you set up a Relay server, but first let's see if we can fix what you are really trying to solve.