New option in pg_basebackup to exclude pg_log files during base backup

Hi all,

Following the discussion in message id - CAHGQGwFFMOr4EcugWHZpAaPYQbsEKDg66VmJ1rveJ6Z-EgaqAg(at)mail(dot)gmail(dot)com<mailto:CAHGQGwFFMOr4EcugWHZpAaPYQbsEKDg66VmJ1rveJ6Z-EgaqAg(at)mail(dot)gmail(dot)com> , I have developed the patch which gives option to user to exclude pg_log directory contents in pg_basebackup.

[Current situation]
During pg_basebackup, all files in pg_log directory will be copied to new backup directory.

[Design]
- Added new non-mandatory option "-S/--skip-log-dir" to pg_basebackup .
- If "skip-log-dir" is specified in pg_basebackup command, then in basebackup, exclude copying log files from standard "pg_log" directory and any other directory specified in Log_directory guc variable. (Still empty folder "pg_log"/$Log_directory will be created)
- In case, pg_log/$Log_directory is symbolic link, then an empty folder will be created

[Advantage]
It gives an option to user to avoid copying of large log files if they doesn't wish to and hence can save memory space.

Attached the patch.

Thanks & Regards,
Vaishnavi
Fujitsu Australia