Hi,
Thank you for developing this feature.
I think adding escape sequence for cluster_name is useful too.
> Is the reason for 'C' in upper-case to avoid possible conflict with
> 'c' of log_line_prefix? I'm not sure that preventive measure is worth
> doing. Looking the escape-sequence spec alone, it seems to me rather
> strange that an upper-case letter is used in spite of its lower-case
> is not used yet.
I think %c of log_line_prefix (Session ID) is also useful for postgres_fdw.application_name.
Therefore, how about adding both %c (Session ID) and %C (cluster_name)?
Regards,
Ryohei Takahashi