PostgreSQL has the ability to report the progress of
   certain commands during command execution.  Currently, the only command
   which supports progress reporting is VACUUM.  This may be
   expanded in the future.
  
   Whenever VACUUM is running, the
   pg_stat_progress_vacuum view will contain
   one row for each backend (including autovacuum worker processes) that is
   currently vacuuming.  The tables below describe the information
   that will be reported and provide information about how to interpret it.
   Progress reporting is not currently supported for VACUUM FULL
   and backends running VACUUM FULL will not be listed in this
   view.
  
Table 28.21. pg_stat_progress_vacuum View
| Column | Type | Description | 
|---|---|---|
| pid | integer | Process ID of backend. | 
| datid | oid | OID of the database to which this backend is connected. | 
| datname | name | Name of the database to which this backend is connected. | 
| relid | oid | OID of the table being vacuumed. | 
| phase | text | Current processing phase of vacuum. See Table 28.22. | 
| heap_blks_total | bigint | Total number of heap blocks in the table.  This number is reported
       as of the beginning of the scan; blocks added later will not be (and
       need not be) visited by this VACUUM. | 
| heap_blks_scanned | bigint | Number of heap blocks scanned.  Because the
       visibility map is used to optimize scans,
       some blocks will be skipped without inspection; skipped blocks are
       included in this total, so that this number will eventually become
       equal to heap_blks_totalwhen the vacuum is complete.
       This counter only advances when the phase isscanning heap. | 
| heap_blks_vacuumed | bigint | Number of heap blocks vacuumed.  Unless the table has no indexes, this
       counter only advances when the phase is vacuuming heap.
       Blocks that contain no dead tuples are skipped, so the counter may
       sometimes skip forward in large increments. | 
| index_vacuum_count | bigint | Number of completed index vacuum cycles. | 
| max_dead_tuples | bigint | Number of dead tuples that we can store before needing to perform an index vacuum cycle, based on maintenance_work_mem. | 
| num_dead_tuples | bigint | Number of dead tuples collected since the last index vacuum cycle. | 
Table 28.22. VACUUM phases
| Phase | Description | 
|---|---|
| initializing | VACUUMis preparing to begin scanning the heap.  This
       phase is expected to be very brief. | 
| scanning heap | VACUUMis currently scanning the heap.  It will prune and
       defragment each page if required, and possibly perform freezing
       activity.  Theheap_blks_scannedcolumn can be used
       to monitor the progress of the scan. | 
| vacuuming indexes | VACUUMis currently vacuuming the indexes.  If a table has
       any indexes, this will happen at least once per vacuum, after the heap
       has been completely scanned.  It may happen multiple times per vacuum
       if maintenance_work_mem is insufficient to
       store the number of dead tuples found. | 
| vacuuming heap | VACUUMis currently vacuuming the heap.  Vacuuming the heap
       is distinct from scanning the heap, and occurs after each instance of
       vacuuming indexes.  Ifheap_blks_scannedis less thanheap_blks_total, the system will return to scanning
       the heap after this phase is completed; otherwise, it will begin
       cleaning up indexes after this phase is completed. | 
| cleaning up indexes | VACUUMis currently cleaning up indexes.  This occurs after
       the heap has been completely scanned and all vacuuming of the indexes
       and the heap has been completed. | 
| truncating heap | VACUUMis currently truncating the heap so as to return
       empty pages at the end of the relation to the operating system.  This
       occurs after cleaning up indexes. | 
| performing final cleanup | VACUUMis performing final cleanup.  During this phase,VACUUMwill vacuum the free space map, update statistics
       inpg_class, and report statistics to the statistics
       collector.  When this phase is completed,VACUUMwill end. |