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NetWork Probes

The network probes monitor the transfer of information from the MySQL

server and clients of all types

over the network. The probes are defined as follows:

net-read-start() net-read-done(status, bytes) net-write-start(bytes) net-write-done(status)

•    net-read-start: Triggered when a network read operation is started.

•    net-read-done: Triggered when the network read operation completes. The status is an

integer representing the return status for the operation, 0 for success and 1 for failure. The bytes

argument is an integer specifying the number of bytes read during the process.

•    net-start-bytes: Triggered when data is written to a network Socket. The single argument,

bytes, specifies the number of bytes written to the network Socket.

•    net-write-done: Triggered when the network write operation has completed. The single

argument, status, is an integer representing the return status for the operation, o for success and l for failure.

You can use the network probes to monitor the time spent reading from and writing to network clients

during execution. The following D script provides an example of this. Both the cumulative time for the

read or write is calculated, and the number of bytes. Notę that the dynamie variable size has been

inereased (using the dyrwarsize option) to cope with the rapid firing of the individual probes for the network reads/writes.