Solved

Oracle 9i Histogram Help

Posted on 2004-09-10
7
1,114 Views
Last Modified: 2008-01-09
I am trying to implement histograms and have been following Burleson's method of implementing.  I'm on Oracle 9i Rel 2 Ver 9.2.0.5 on Windows 2000 Advanced Server. I have run :

begin
   dbms_stats.gather_schema_stats(
      ownname          => 'SNAP',
      estimate_percent => dbms_stats.auto_sample_size,
      method_opt       => 'for all columns size skewonly',
      degree           => 4
   );
end;
/

And am trying to interpret what I am seeing in DBA_histograms.  I am the first one to run histograms on this db and there are only about 300 tables in this schema with about 15 columns or so per table.  I am ending up with a lot of rows in this table.  I wasn't expecting that.  I am expecting one row per histogram and one histogram per column.   Is that right?  Can histograms be deleted?  Using delete schema stats didn't do it....


0
Comment
Question by:DonFreeman
[X]
Welcome to Experts Exchange

Add your voice to the tech community where 5M+ people just like you are talking about what matters.

  • Help others & share knowledge
  • Earn cash & points
  • Learn & ask questions
  • 3
  • 3
7 Comments
 
LVL 1

Author Comment

by:DonFreeman
ID: 12027359
Here is what I got:

TEST1-DFREEMAN> select count(*) from dba_histograms;

                                          COUNT(*)
--------------------------------------------------
                                             76318

1 row selected.

TEST1-DFREEMAN> select count(*) from all_tab_columns where owner ='SNAP';

                                          COUNT(*)
--------------------------------------------------
                                              5345
0
 
LVL 13

Expert Comment

by:riazpk
ID: 12027535
0
 
LVL 1

Author Comment

by:DonFreeman
ID: 12027576
I can't get this link to work.  I have been on AskTom quite a bit this morning researching this issue but I can't find a description of how the dba_histogram table works.
0
Technology Partners: We Want Your Opinion!

We value your feedback.

Take our survey and automatically be enter to win anyone of the following:
Yeti Cooler, Amazon eGift Card, and Movie eGift Card!

 
LVL 4

Expert Comment

by:mottor
ID: 12028508
Oracle docs:
 Choosing the Number of Buckets for a Histogram
http://download-west.oracle.com/docs/cd/A91202_01/901_doc/server.901/a87503/stats.htm#27027
0
 
LVL 1

Author Comment

by:DonFreeman
ID: 12044048
I'm struggling through this.  I'm trying to figure out exactly how to clear that histogram information out of dba_histograms.   I only have this database part-time and would like to return it to pre-histogram state.  I did it running skewonly method.  I tried to remove it using dbms_stats.delete_schema_stats.   The links aren't working for me guys.  I have links to 500 docs.  What I need is an unambiguous explanation of 'middle-level' of how this works.  

Also, I tried to turn on schema monitoring using:  NEDSSART-DFREEMAN> BEGIN
  2   DBMS_STATS.ALTER_SCHEMA_TABLE_MONITORING (
  3     ownname=>'SNAP',
  4     monitoring=>TRUE);
  5  END;
  6  /
 DBMS_STATS.ALTER_SCHEMA_TABLE_MONITORING (
            *
ERROR at line 2:
ORA-06550: line 2, column 13:
PLS-00302: component 'ALTER_SCHEMA_TABLE_MONITORING' must be declared
ORA-06550: line 2, column 2:
PL/SQL: Statement ignored
0
 
LVL 4

Accepted Solution

by:
mottor earned 125 total points
ID: 12045199
use DBMS_STATS.ALTER_SCHEMA_TAB_MONITORING
not DBMS_STATS.ALTER_SCHEMA_TABLE_MONITORING
0
 
LVL 4

Expert Comment

by:mottor
ID: 12045847
Now,
There is another link:
http://asktom.oracle.com/pls/ask/f?p=4950:8:6965706299122648996::NO::F4950_P8_DISPLAYID,F4950_P8_CRITERIA:3126073805757,
It contains article (search fo 'Article'), which is unambiguous explanation of 'middle-level' .
And be sure you read the whole.

Regards.
0

Featured Post

Free Tool: Path Explorer

An intuitive utility to help find the CSS path to UI elements on a webpage. These paths are used frequently in a variety of front-end development and QA automation tasks.

One of a set of tools we're offering as a way of saying thank you for being a part of the community.

Question has a verified solution.

If you are experiencing a similar issue, please ask a related question

Configuring and using Oracle Database Gateway for ODBC Introduction First, a brief summary of what a Database Gateway is.  A Gateway is a set of driver agents and configurations that allow an Oracle database to communicate with other platforms…
From implementing a password expiration date, to datatype conversions and file export options, these are some useful settings I've found in Jasper Server.
This video shows information on the Oracle Data Dictionary, starting with the Oracle documentation, explaining the different types of Data Dictionary views available by group and permissions as well as giving examples on how to retrieve data from th…
Via a live example, show how to restore a database from backup after a simulated disk failure using RMAN.

691 members asked questions and received personalized solutions in the past 7 days.

Join the community of 500,000 technology professionals and ask your questions.

Join & Ask a Question