From: Narayanan V [mailto:vnarayanan.email@gmail.com]
> I think what Takayuki is trying to say is that streaming replication works
> by sending the contents of the WAL archives to the standbys. If archive_mode
> was NOT set to always, and if you wanted to archive WAL logs in the standby
> you would need to rely on the process_command and make it ship the WAL logs
> (to the standby). This causes the same WAL log information to be shipped
> in two places,
>
> 1. Through Streaming Replication
> 2. By the process_command
>
> This redundant shipping of the same information is expensive and consumes
> network bandwidth. This can be avoided with the use of archive_mode=always.
>
> archive_mode=always makes the standby archive the WAL logs it receives,
> thus avoiding the requirement of having to ship it separately.
Exactly. (archive_command, not process_command)
Thanks, Narayanan.
Regards
Takayuki Tsunakawa