Re: Can't access SOME table's statistics.

The advice Jerry and others give is correct as usual. I'd just add that a probable cause for this state of affairs is that the tables were created after the last analysis. In a production environment where you are using the cost based optimiser, statistics need to be collected *regularly* by for example a cron job. This is because statistics that are out of date cause erratic results in query performance. The time period *regularly* will vary according to the needs of your system.

hth

--
Niall Litchfield
Oracle DBA
Audit Commission UK
"Jerry Gitomer" <jgitomer_at_erols.com> wrote in message
news:20000801.5085100_at_localhost.localdomain...


Sounds like all of your tables weren't analyzed.  Try

ANALYZE TABLE <table_name> ESTIMATE STATISTICS

and then check the contents of USER_TABLES.  If the missing values are
filled in go ahead and analyze the rest of your tables.  Depending on
the number of rows and the distribution of the values across the
indexes you may prefer to COMPUTE statistics rather than estimate
them.


>>>>>>>>>>>>>>>>>> Original Message <<<<<<<<<<<<<<<<<<

On 7/31/00, 2:11:48 PM, "Robert Wagner" <RobertWagner_at_alum.mit.edu>
wrote regarding Can't access SOME table's statistics.:




> I presently have 8 tables in a schema. When I do a SELECT on

 USER_TABLES I


> see all

> of them, but I don't get anything in statistical columns like

 NUM_ROWS,


> BLOCKS,

> EMPTY_BLOCKS, and AVG_SPACE for three of the tables. Is there

 something like


> (this is pure speculation):

 


> ENABLE STATISTICS_COLLECTION ON mytable

 


> that would be required to for this data to be collected?

 


> When I do an export from the schema, the CREATE TABLE statements don't

 seem


> different in any

> way that could explain this.

 


> TIA  >>> Robert  (still being surprised by Oracle)