zero value in statistics collector's result - Mailing list pgsql-performance

Hi,

When I use the statistics collector to see the number of IO, I always get zero in almost all of columns. I really want to know the reason for that.

The result of statistics view:

# select * from pg_statio_user_tables;

 relid | schemaname | relname | heap_blks_read | heap_blks_hit | idx_blks_read | idx_blks_hit | toast_blks_read | toast_blks_hit | tidx_blks_read | tidx_blks_hit

-------+------------+---------+----------------+---------------+---------------+--------------+-----------------+----------------+----------------+---------------

 16386 | public     | tab     |              0 |             0 |             0 |            0 |                 |                |                |             

(1 row)

# select * from pg_statio_user_indexes;

 relid | indexrelid | schemaname | relname | indexrelname | idx_blks_read | idx_blks_hit

-------+------------+------------+---------+--------------+---------------+--------------

 16386 |      24581 | public     | tab     | idx_tab_a2   |             0 |            0

(1 row)

I’ve set:

stats_start_collector = on

stats_row_level = on

stats_block_level = on

and I think that the statistics collector should be running, because:

$ ps aux|grep stats

postgres  3688  0.0  0.0   7272   648 ?        Ss   00:48   0:00 postgres: stats collector process                    

postgres 29790  0.0  0.0   4004   712 pts/2    S+   04:44   0:00 grep stats

Any help would be really appreciated.

Regards,

Yinan