Hello! - The approximate size of the tablespace, in kilobytes (1024 bytes), - if progress report has been requested; otherwise it's null. + The approximate amount of data that will be sent for the + tablespace, in kilobytes (1024 bytes), if progress report has been + requested; otherwise it's null. For an incremental backup this can + be much smaller than the size of the tablespace, since files that + have changed only partially are sent as incremental files.
One nit to this: shouldn't it also mention unchanged files? For example: For an incremental backup this can be much smaller than the size of the tablespace, since relation files that are unchanged or only partly changed since the prior backup are sent as incremental files containing just the modified blocks.
