Progress more than 100% ??

[Rodgelius]

Very interesting experience, why can it be?

[Fri Aug 18 12:00:23 2017] (somedb:public.sometable) Vacuum initial: 2394828 pages left, duration 201.816 seconds.
[Fri Aug 18 12:03:12 2017] (somedb:public.sometable) Bloat statistics with pgstattuple: duration 169.006 seconds.
[Fri Aug 18 12:03:12 2017] (somedb:public.sometable) Statistics: 2394828 pages (3944168 pages including toasts and indexes) , approximately 48.560% (1162809 pages) can be compacted reducing the size by 8.872GB.
[Fri Aug 18 12:03:12 2017] (somedb:public.sometable) Update by column: ns.
[Fri Aug 18 12:03:12 2017] (somedb:public.sometable) Set pages/round: 5.
[Fri Aug 18 12:03:12 2017] (somedb:public.sometable) Set pages/vacuum: 47897.
[Fri Aug 18 12:04:12 2017] (somedb:public.sometable) Progress: 1%, 13485 pages completed.
[Fri Aug 18 12:05:13 2017] (somedb:public.sometable) Progress: 2%, 26365 pages completed.
[Fri Aug 18 12:06:13 2017] (somedb:public.sometable) Progress: 3%, 39265 pages completed.
[Fri Aug 18 12:07:13 2017] (somedb:public.sometable) Progress: 4%, 51825 pages completed.
[Fri Aug 18 12:08:13 2017] (somedb:public.sometable) Progress: 5%, 64265 pages completed.
...
[Fri Aug 18 13:24:22 2017] (somedb:public.sometable) Progress: 93%, 1084660 pages completed.
[Fri Aug 18 13:25:22 2017] (somedb:public.sometable) Progress: 96%, 1120520 pages completed.
[Fri Aug 18 13:26:22 2017] (somedb:public.sometable) Progress: 99%, 1154950 pages completed.
[Fri Aug 18 13:27:22 2017] (somedb:public.sometable) Progress: 102%, 1188925 pages completed.
[Fri Aug 18 13:28:22 2017] (somedb:public.sometable) Progress: 105%, 1223730 pages completed.

[webervin]

same as pg_basebackup, your database can grow between Fri Aug 18 12:04:12 and Fri Aug 18 13:28:22 2017, (also pgcompacttable does produce new pages with it's updates), maybe your autovaccum could not keep up?