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zero value in statistics collector's result

From: "Yinan Li" <yinanli(at)cse(dot)ust(dot)hk>
To: <pgsql-performance(at)postgresql(dot)org>
Subject: zero value in statistics collector's result
Date: 2007-09-23 17:00:24
Message-ID: 003801c7fe03$3c3f8020$b4be8060$@ust.hk (view raw or flat)
Thread:
Lists: 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

 

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