Log_process MTA option
Transaction logging MTA options:
log_process (0 or 1)
log_process MTA option controls whether or not the ID of the process is saved in the
mail.log file (and the
connection.log file, if a separate connection log is used).
A value of 1 enables process ID logging. A value of 0 disables it. As of MS 6.3p1, enabling XML format (
log_format set to 4) causes the default for
log_process to be 1; with any other format, the default is 0, as in previous versions.
The process ID will be logged after the date and time stamps in log entries---and after the node name, if
log_node is also enabled. In XML-compatible format (
log_format set to 4), process ID logging, if enabled, appears is the
pi attribute. The process ID field itself will consist of the process ID in a hexadecimal representation followed by a period, next in the case of a multithreaded channel the thread ID followed by a period, followed by a (per process) sequence number that uniquely identifies the logging operation as a whole. That is, in the case of a single threaded channel
or in the case of a multithreaded channel
Note in particular that via the process id and thread id, TCP/IP channel message enqueue/dequeue (E/D) records may be correlated with SMTP connection open/close (O/C) records. The sequence number provides the ability to identify all the entries associated with the processing a a specific queue entry.
log_processis one of the most useful MTA logging options for correlating between multiple transaction records relating to the same message, observing the timing between entries, etc.