Re: What do null column values for pg_stat_progress_vacuum mean?

On 3/5/20 6:39 PM, Mark Haylock wrote:
> Hi,
>
> We have an autovacuum process that has been running for almost 27 hours:
>
> SELECT * FROM pg_stat_activity WHERE pid = 11731;
> -[ RECORD 1 ]----+---------------------------------------
> datid | 16385
> datname | database_name
> pid | 11731
> usesysid |
> usename |
> application_name |
> client_addr |
> client_hostname |
> client_port |
> backend_start | 2020-03-04 23:40:14.828138+00
> xact_start | 2020-03-04 23:40:14.849367+00
> query_start | 2020-03-04 23:40:14.849367+00
> state_change | 2020-03-04 23:40:14.849368+00
> wait_event_type |
> wait_event |
> state | active
> backend_xid |
> backend_xmin | 3801997676
> query | autovacuum: VACUUM public.responses
> backend_type | autovacuum worker
>
> A row shows up in pg_stat_progress_vacuum, but it contains null values
> for every column.
>
> SELECT * FROM pg_stat_progress_vacuum WHERE pid = 11731;
> -[ RECORD 1 ]------+---------------
> pid | 11731
> datid | 16385
> datname | d2j496215lfs41
> relid |
> phase |
> heap_blks_total |
> heap_blks_scanned |
> heap_blks_vacuumed |
> index_vacuum_count |
> max_dead_tuples |
> num_dead_tuples |
>
> I see nothing in the documentation to suggest that this is an expected
> state - what does it mean?

Not sure, but you might try:

https://www.postgresql.org/docs/10/view-pg-locks.html

The pid column can be joined to the pid column of the pg_stat_activity
view to get more information on the session holding or awaiting each
lock, for example

SELECT * FROM pg_locks pl LEFT JOIN pg_stat_activity psa
ON pl.pid = psa.pid;

>
> Thanks,
> Mark.
>
>

--
Adrian Klaver
adrian(dot)klaver(at)aklaver(dot)com