postgres=# select *,heap_blks_scanned/heap_blks_total::numeric*100 AS percents  from pg_stat_progress_vacuum;
....
-[ RECORD 3 ]------+----------------------------
pid                | 6149
datid              | 16403
datname            | db_name
relid              | 13664079
phase              | vacuuming indexes
heap_blks_total    | 37789852
heap_blks_scanned  | 23860705
heap_blks_vacuumed | 0
index_vacuum_count | 0
max_dead_tuples    | 178956970
num_dead_tuples    | 178956680
percents           | 63.14050925629452055000

....
select(0, NULL, NULL, NULL, {0, 32393}) = 0 (Timeout)
read(393, "\374\\\0\0\3008\205j\0\0\0\0D\3@\23\360\37\4 \0\0\0\0@\223 \0\340\237 \0"..., 8192) = 8192
futex(0x7fe0e2ba7538, FUTEX_WAIT_BITSET|FUTEX_CLOCK_REALTIME, 0, NULL, ffffffff) = 0
futex(0x7fe0e2ba7538, FUTEX_WAIT_BITSET|FUTEX_CLOCK_REALTIME, 0, NULL, ffffffff) = -1 EAGAIN (Resource temporarily unavailable)
futex(0x7fe0e2ba0838, FUTEX_WAKE, 1)    = 1
futex(0x7fe0e2ba7538, FUTEX_WAIT_BITSET|FUTEX_CLOCK_REALTIME, 0, NULL, ffffffff) = 0
select(0, NULL, NULL, NULL, {0, 80000}) = 0 (Timeout)
read(393, "DV\0\0\300\266,\377\0\0\0\0\20\3\20\24\360\37\4 \0\0\0\0\20\224 \0\340\237 \0"..., 8192) = 8192
futex(0x7fe0e2ba7538, FUTEX_WAIT_BITSET|FUTEX_CLOCK_REALTIME, 0, NULL, ffffffff) = -1 EAGAIN (Resource temporarily unavailable)
select(0, NULL, NULL, NULL, {0, 80000}) = 0 (Timeout)
....

postgres  6149  3.6 23.4 31306868 30547540 ?   Rs   Dec15 177:33  \_ postgres: autovacuum worker process    db_name

autovacuum_analyze_scale_factor = 0.01
autovacuum_freeze_max_age = 200000000
autovacuum = on
checkpoint_completion_target = 0.7
default_statistics_target = 1000
data_directory = '/pgdata/10'
datestyle = 'iso, mdy'
default_text_search_config = 'pg_catalog.english'
dynamic_shared_memory_type = posix
effective_cache_size = 84GB
hot_standby = on
lc_messages = 'C'
lc_monetary = 'C'
lc_numeric = 'C'
lc_time = 'C'
listen_addresses = '*'
log_timezone = 'UTC'
maintenance_work_mem = 2GB
max_connections = 1000
max_replication_slots = 10
max_wal_senders = 10
max_worker_processes = 10
port = 5432
shared_buffers = 28GB
timezone = 'UTC'
vacuum_freeze_min_age = 30000000
wal_buffers = 16MB
wal_keep_segments = 16384
wal_level = replica
wal_sender_timeout = 60000
work_mem = 1024MB
log_destination = syslog

db_name=# SELECT relname, n_dead_tup FROM pg_stat_user_tables WHERE relname = 'articles';
 relname  | n_dead_tup
----------+------------
 articles |  214653365
(1 row)

db_name=# SELECT reltuples AS approximate_row_count FROM pg_class WHERE relname = 'articles';
 approximate_row_count
-----------------------
           2.23663e+07
(1 row)

db_name=# SELECT reltuples AS approximate_row_count FROM pg_class WHERE relname = 'articles';
 approximate_row_count
-----------------------
           2.23663e+07
(1 row)
```
22 400 000 записей

db_name=# SELECT relname, n_dead_tup, n_live_tup FROM pg_stat_user_tables WHERE relname = 'articles';
 relname  | n_dead_tup | n_live_tup
----------+------------+------------
 articles |  214779420 |   23832015
(1 row)

select null_frac, most_common_vals, most_common_freqs from pg_stats where tablename = 'articles' and attname = 'proc_phase';
\di+ new_articles_proc_phase_idx

# select null_frac, most_common_vals, most_common_freqs from pg_stats where tablename = 'articles' and attname = 'proc_phase';
 null_frac |  most_common_vals  |  most_common_freqs
-----------+--------------------+---------------------
         0 | {to_freeze,culled} | {0.709537,0.290463}

\di+ new_articles_proc_phase_idx
                                    List of relations
 Schema |            Name             | Type  |  Owner   |  Table   | Size  | Description
--------+-----------------------------+-------+----------+----------+-------+-------------
 public | new_articles_proc_phase_idx | index | postgres | articles | 25 GB |

select *,heap_blks_scanned/heap_blks_total::numeric*100 AS percents  from pg_stat_progress_vacuum where pid=6149;

./pgcompacttable \
    -U postgres \
    --dbname db_test \
    --table articles \
    --no-initial-vacuum \
    --verbose

# SELECT relname, n_dead_tup, n_live_tup FROM pg_stat_user_tables WHERE relname = 'articles';
 relname  | n_dead_tup | n_live_tup
----------+------------+------------
 articles |     0 |          0

# SELECT relname, n_dead_tup, n_live_tup FROM pg_stat_user_tables WHERE relname = 'articles';
 relname  | n_dead_tup | n_live_tup
----------+------------+------------
 articles |     148644 |          0
(1 row)

[Thu Dec 20 19:15:36 2018] (database:public.articles) Progress: 29%,  9951040 pages completed.

# SELECT relname, n_dead_tup, n_live_tup FROM pg_stat_user_tables WHERE relname = 'articles';
 relname  | n_dead_tup | n_live_tup
----------+------------+------------
 articles |  216520661 |   24025528
(1 row)