Statistics on Partioned Table

Hi,
dbms_stats.gather_schema_stats('SCHEMA') will compute statistics for partioned tables and generate the execution path?
Regards,
Vijayaraghavan K

Vijayaraghavan Krishnan wrote:
Hi,
dbms_stats.gather_schema_stats('SCHEMA') will compute statistics for partioned tables and generate the execution path?GATHER_SCHEMA_STATS by default gathers partition level and global statistics in 9i. In 10g and 11g "AUTO" is the default value for "GRANULARITY" which means that Oracle itself decides on which level to gather the statistics depending on the partitioning type.
It doesn't "generate the execution path" but gathering statistics can (and usually will) influence the decisions of the cost based optimizer.
Regards,
Randolf
Oracle related stuff blog:
http://oracle-randolf.blogspot.com/
SQLTools++ for Oracle (Open source Oracle GUI for Windows):
http://www.sqltools-plusplus.org:7676/
http://sourceforge.net/projects/sqlt-pp/

Similar Messages

Disable Statistics for specific Tables

Is it possible to disable statistics for specific tables???

If you want to stop gathering statistics for certain tables, you would simply not call DBMS_STATS.GATHER_TABLE_STATS on those particular tables (I'm assuming that is how you are gathering statistics at the moment). The old statistics will remain around for the CBO, but they won't be updated. Is that really what you want?
If you are currently using GATHER_SCHEMA_STATS to gather statistics, you would have to convert to calling GATHER_TABLE_STATS on each table. You'll probably want to have a table set up that lists what tables to exclude and use that in the procedure that calls GATHER_TABLE_STATS.
Justin
Distributed Database Consulting, Inc.
http://www.ddbcinc.com/askDDBC

Import Table Statistics to another table

Hi,
Just like to know if I can use dbms_stats.import_table_stats to import table statistics to another table?
Scenario:
I exported the table statistics of the table (T1) using the command below.
exec dbms_stats.export_table_stats('<user>','T1',NULL,'<stat table>');
PL/SQL procedure successfully completed.
And then, I have another table named T2, T1 and T2 are identical tables. T2 does not have statistics (I intentionally did not run gather statistics). I am wondering
if I can import table statistics from T1 to T2 using dbms_stats package?.
For what I understand, statistics can be imported back at the same table which is T1 but not for another table using dbms_stat package. If I am wrong, anyone can correct me.
Thanks

hi
just try ;-) you lose nothing probably,
check afterwards last_analyzed value for that table in user_tables
if something is wrong, run regular stats

How to disable automatic statistics collections on tables

Hi
I am using Oracle 10g and we have few tables which are frequently truncated and news rows added to it. Oracle automatically analyzes the table by some means which collects statistics of the table but at the wrong time(when the table is empty). This makes my query to do a full table scan rather using indexes since the statistics was collected when the table was empty.Could any one please let me know how to disable the automatic statistics collection feature of Oracle?
Cheers
Anantha PV

Hi
I am using Oracle 10g and we have few tables which
are frequently truncated and news rows added to it.
Oracle automatically analyzes the table by some means
which collects statistics of the table but at the
wrong time(when the table is empty). This makes my
query to do a full table scan rather using indexes
since the statistics was collected when the table was
empty.Could any one please let me know how to disable
the automatic statistics collection feature of
Oracle?
First of all I think it's important that you understand why Oracle collects statistics on these tables: Because it considers the statistics of the object to be missing or stale. So if you just disable the statistics gathering on these tables then you won't have statistics at all or outdated statistics.
So as said by the previous posts you should gather the statistics manually yourself anyway. If you do so right after loading the data into the truncated table, you don't need to disable the automatic statistics gathering as it only processes objects that are stale or don't have statistics at all.
If you still think that you need to disable it there are several ways to accomplish it:
As already mentioned, for particular objects you can lock the statistics using DBMS_STATS.LOCK_TABLE_STATS, or for a complete schema using DBMS_STATS.LOCK_SCHEMA_STATS. Then these statistics won't be touched by the automatic gathering job. You still can gather statistics using the FORCE=>true option of the GATHER__STATS procedures.
If you want to change the automatic gathering job that it only gathers statistics on objects owned by Oracle (data dictionary, AWR etc.), then you can do so by calling DBMS_STATS.SET_PARAM('AUTOSTATS_TARGET', 'ORACLE'). This is the recommended method.
If you disable the schedule job as mentioned in the documentation by calling DBMS_SCHEDULER.DISABLE('GATHER_STATS_JOB') then no statistics at all will be gathered automatically, causing your data dictionary statistics to be become stale over time, which could lead to suboptimal performance of queries on the data dictionary.
All this applies to Oracle 10.2, some of the features mentioned might not be available in Oracle 10.1 (as you haven't mentioned your version of 10g).
Regards,
Randolf
Oracle related stuff blog:
http://oracle-randolf.blogspot.com/
SQLTools++ for Oracle:
http://www.sqltools-plusplus.org:7676/
http://sourceforge.net/projects/sqlt-pp/

Statistics Analysis on Tables that are often empty

Right now I'm dealing with a user application that was originally developed in Ora10g. Recently the database was upgraded to Ora11g, and the schema and data was imported successfully.
However, since the user started using Ora11, some of their applications have been running slower and slower. I'm just wondering if the problem could be due to statistics.
The application has several tables which contains temporary data. Usually these tables are empty, although when a user application runs they are populated, and queried against, and then at the end the data is deleted. (Its this program that's running slower and slower.)
I'm just wondering if the problem could be due to a problem with user statistics.
When I look at the 'last_analyzed' field in user_tables, the date goes back to the date of last import. I know Oracle regularly updates statistics, so what I suspect is happening is that, by luck, Oracle has only been gathering statistics when the tables are empty. (And since the tables are empty, the statistics are of no help in optimizing the DB.)
Am I on the right track?
And if so, is there a way to automatically trigger a statistics gather job when a table gets above a certain size?
System details:
Oracle: 11gR2 (64 bit) Standard version
File System: ASM (GRID infrastructure)

Usually these tables are empty, although when a user application runs they are populated, and queried against, and then at the end the data is deletedYou have three options (and depending on how the data changes, you might find that not all temporary tables work best with the same option) :
1. Load representative data into the temporary table, collect statistics (including any histograms that you identify as necessary) and then lock the statistics
2. Modify the job to re-gather statistics immediately after a temporary table is populated
3. Delete statistics and then lock the statistics and check the results (execution plan and performance) when the optimizer uses dynamic sampling
Note : It is perfectly reasonable to create indexes on temporary tables -- provided that you DO create the correct indexes. If jobs are querying the temporary tables for the full data set (all rows) indexes are a hindrance. If there are many separate queries against the temporary table, each query retrieiving a small set of rows, an index or two may be beneficiial. Also some designs do use unique indexes to enforce uniqueness when the tables are loaded.
Hemant K Chitale

Create new CBO statistics for the tables

Dear All,
I am facing bad performance in server.In SM50 I see that the read and delete process at table D010LINC takes
a longer time.how to create new CBO statistics for the tables D010TAB and D010INC. Please suggest.
Regards,
Kumar

Hi,
I am facing problem in when save/activating any problem ,so sap has told me to create new CBO statistics for the tables D010TAB and D010INC
Now as you have suggest when tx db20
Table D010LINC
there error comes Table D010LINC does not exist in the ABAP Dictionary
Table D010TAB
     Statistics are current (|Changes| < 50 %)
New Method           C
New Sample Size
Old Method           C                       Date                 10.03.2010
Old Sample Size                              Time                 07:39:37
Old Number                51,104,357         Deviation Old -> New       0 %
New Number                51,168,679         Deviation New -> Old       0 %
Inserted Rows                160,770         Percentage Too Old         0 %
Changed Rows                       0         Percentage Too Old         0 %
Deleted Rows                  96,448         Percentage Too New         0 %
Use                  O
Active Flag          P
Analysis Method      C
Sample Size
Please suggest
Regards,
Kumar

How to Update the statistics of a table

Dear Experts,
I want to update the statistics of a table D010INC table.How can i update it.
Plz provide me detailed steps.
Regards,
Farook.
Edited by: farook shaik on Dec 15, 2008 1:04 PM

check this SAP help
http://help.sap.com/saphelp_nw04/Helpdata/EN/df/455e97747111d6b25100508b6b8a93/content.htm

How to build statistics for a table, its urgent, points will be rewarded

Hi friends,
I want to create a statistics for MSEG table in production server, because its not up to date.
Total no. of entries available in table is 2,30,000.
My O/S windows2003 (cluster)/oracle9.2/ ECC 5.
I need a step by step procedure to build or create statistics using DB20.
Regards,
s.senthil kumar

Hi stefan,
Thanks 4 ur reply.
I need some more clarification on db20.
Wt are the values I have to give on following fields.
New method and new sample size.
anyfields or chek box I need to fill before create new statistics?
My current screen values on following fields.
new method = 'C'. new sample size = ' '.
old method = 'C'. old sample size = '   '.
Old Number   5,965         Deviation Old -> New   3,669
New Number 24,834       Deviation New -> Old      97-
Inserted Rows 0              Percentage Too Old         0
Changed Rows 0            Percentage Too Old         0
Deleted Rows     0           Percentage Too New         0
Use                  A
Active Flag        A
Analysis Method      C
and history check box is marked.
Can I run DB20 while server is running or at peak time?
Regards,
s.senthil kumar

Gathering daily statistics of a table using DBMS_STATS..!!

Hi all,
Can please somebody help me for how to collect daily statistics of a table..!!
executing the DBMS_stats is fine but when i assign as a job using OEM the job never starts. It just shows the status as job submitted but never executes..
Is there any other way to execute the DBMS_STATS daily...??

In 10g, it is executed daily at 22:00 by default.
Otherwise, you can execute something like
begin
dbms_job.isubmit(job       => 1,
                 what      => 'BEGIN
DBMS_STATS.GATHER_DATABASE_STATS (
estimate_percent      => DBMS_STATS.AUTO_SAMPLE_SIZE,
block_sample          => TRUE,
method_opt            => ''FOR ALL COLUMNS SIZE AUTO'',
degree                => 6,
granularity           => ''ALL'',
cascade               => TRUE,
options               => ''GATHER STALE''
END;',
                 next_date => sysdate + 2,
                 interval => 'TRUNC(SysDate +1 ) + 22/24',
                 no_parse => TRUE);
end;
commit;Make sure you commit.

Unable to generate statistics for the table

I have got a staging table of more than 600 columns which has got range portioning. Size of the table is 4GB. The average size of the row is around 3 MB. I have created a Functional index on one of the column ABC VARCHAR2(50) and it has only number values. Now when I try generating statistics for this table through ANALYZE or DBMS_STAT, it gives Invalid Number error but when I drop this index and try analyzing, it works.
Executed TO_NUMBER(ABC) query on the table and it works fine.
I have got Functional Indexes on other tables also but I don't get such problem with those tables. I tried dropping the index and re-creating it but it didn't work out.
I was suspecting DATA BLOCK CORRUPTION so checked ALERT LOG and TRACE FILES but found nothing.
So what is this magic called?

I am using TO_NUMBER on the column.
I have checked the MetaLink for the same problem but could not find anything on that. I still suspect datafile error which I am unable to get in ALERT LOG or TRACE FILES. So I am going to try it this way:
1) Create new Tablespace with New Datafile
2) Transfer the table from existing Tablespace to new Tablespace
3) Create the functional index in the same new Tablespace
4) Try generating the statistics.
5) If it works then create seprate Tablespace for data and Index.
Hope it works !!
Thanks for the reply guys.

How to Load 100 Million Rows in Partioned Table

Dear all,
I a workling in VLDB application.
I have a Table with 5 columns
For ex- A,B,C,D,DATE_TIME
I CREATED THE RANGE (DAILY) PARTIONED TABLE ON COLUMN (DATE_TIME).
AS WELL CREATED NUMBER OF INDEX FOR EX,
INDEX ON A
COMPOSITE INDEX ON DATE_TIME,B,C
REQUIREMENT
NEED TO LOAD APPROX 100 MILLION RECORDS IN THIS TABLE EVERYDAY ( IT WILL LOAD VIA SQL LOADER OR FROM TEMP TABLE (INSERT INTO ORIG SELECT * FROM TEMP)...
QUESTION
TABLE IS INDEXED SO I AM NOT ABLE TO USE SQLLDR FEATURE DIRECT=TRUE.
SO LET ME KNOW WHAT THE BEST AVILABLE WAY TO LOAD THE DATA IN THIS TABLE ????
Note--> PLEASE REMEMBER I CAN'T DROP AND CREATE INDEX DAILY DUE TO HUGE DATA QUANTITY.

Actually a simpler issue then what you seem to think it is.
Q. What is the most expensive and slow operation on a database server?
A. I/O. The more I/O, the more latency there is, the longer the wait times are, the bigger the response times are, etc.
So how do you deal with VLT's? By minimizing I/O. For example, using direct loads/inserts (see SQL APPEND hint) means less I/O as we are only using empty data blocks. Doing one pass through the data (e.g. apply transformations as part of the INSERT and not afterwards via UPDATEs) means less I/O. Applying proper filter criteria. Etc.
Okay, what do you do when you cannot minimize I/O anymore? In that case, you need to look at processing that I/O volume in parallel. Instead of serially reading and writing a 100 million rows, you (for example) use 10 processes that each reads and writes 10 million rows. I/O bandwidth is there to be used. It is extremely unlikely that a single process can fully utilised the available I/O bandwidth. So use more processes, each processing a chunk of data, to use more of that available I/O bandwidth.
Lastly, think DDL before DML when dealing with VLT's. For example, a CTAS to create a new data set and then doing a partition exchange to make that new data set part of the destination table, is a lot faster than deleting that partition's data directly, and then running a INSERT to refresh that partition's data.
That in a nutshell is about it - think I/O and think of ways to use it as effectively as possible. With VLT's and VLDB's one cannot afford to waste I/O.

Display statistics history of tables and indexes

hi,
in display statistics history of tables and indexes i can see only one year old table history, how we can check the table history for more than one year?
Thanks,
Nithin

Welcome to SDN,
Please search on help.sap.com or SDN before you post your query to avoid duplicate thread.
I think below link will clear your doubt. help.sap.com/saphelp_nw70ehp1/helpdata/en/a6/8c933bf687e85de10000000a11402f/frameset.htm

Statistics on temporary table issue

We have a temporary table that causes sometimes a performance issue as the table statistics are not correct. The solution might be to compute the object statistics just before several select statements using the temporary table are executed (this is currently not the case). I think there can still be issues with this approach:
step 1.) Job 1 fills temporary table and gathers statistics on the table
step 2.) Job 1 executes first sql on temporary table
step 3.) Job 2 fills temporary table and gathers statistics on the table
step 4.) Job 2 executes first sql on temporary table using the new statistics
step 5.) Job 1 executes second sql on the table - but has now new (= wrong) table statistics of job 2
Job 1 executes for mandant 1 and job 2 for mandant 2, etc. Some of the "heap-organized" tables are partitioned by mandant.
How can we solve this problem? We consider to partition the temporary table into partitions by mandant, too. Are there other / better solutions?
(Oracle 10.2.0.4)

Hello,
If you don't have statistics on your Temporary Table Oracle will use dynamic sampling instead.
So, you may try to delete the statistics on this Table and then Lock them, as follow:
execute dbms_stats.delete_table_stats('{color:red}schema{color}','{color:red}temporary_table{color}');
execute dbms_stats.lock_table_stats('{color:red}schema{color}','{color:red}temporary_table{color}');You may check the performances as dynamic sampling is also resource consuming.
Hope this help.
Best regards,
Jean-Valentin

Statistics on a table to be collected daily.

Hi,
I have a scenario where a table gets truncated every day at 10 PM before being populated by a billion a two number of records. At 12 AM, the table will be used by warehousing system. How do we gather statistics for this table on a daily basis to see that Oracle accesses this table in the best possible way.
I know that a job something like this...
DECLARE
JOB USER_JOBS.JOB%TYPE;
BEGIN
DBMS_JOB.SUBMIT (JOB, 'BEGIN DBMS_STATS.GATHER_TABLE_STATS ('TABLE_NAME')', to_date ('24/11/2009 23:00', 'dd/mm/yyyy hh24:mi'), sysdate+1);
END;will get the statistics for me,
Is there any other approach??
Thanks,
Aswin.

PROCEDURE GATHER_TABLE_STATS
Argument Name                  Type                    In/Out Default?
OWNNAME                        VARCHAR2                IN
TABNAME                        VARCHAR2                IN
PARTNAME                       VARCHAR2                IN     DEFAULT
ESTIMATE_PERCENT               NUMBER                  IN     DEFAULT
BLOCK_SAMPLE                   BOOLEAN                 IN     DEFAULT
METHOD_OPT                     VARCHAR2                IN     DEFAULT
DEGREE                         NUMBER                  IN     DEFAULT
GRANULARITY                    VARCHAR2                IN     DEFAULT
CASCADE                        BOOLEAN                 IN     DEFAULT
STATTAB                        VARCHAR2                IN     DEFAULT
STATID                         VARCHAR2                IN     DEFAULT
STATOWN                        VARCHAR2                IN     DEFAULT
NO_INVALIDATE                  BOOLEAN                 IN     DEFAULT
STATTYPE                       VARCHAR2                IN     DEFAULT
FORCE                          BOOLEAN                 IN     DEFAULTYour post contains error.
Provide all mandatory arguments

Calculating Statistics on DR$ tables

I have several DR$ tables in my database. I think they come because I am using text indexes. This is third party application. When I run dbms_stats to do statistics on entire schema, it never calculates statistics on DR$ tables. Somewhere I had read that Oracle uses rule base optimizer , yes rule based optimizer for these tables. I am on Oracle 10.2.0.4. When I rebuild text indexes, it never computes statistics on these tables as well.
What is stage that some of my queries involving text indexes run slow that database control (database tuning advisor) is recommending run statistics on these tables!!! Can someone provide their thoughts on it?

I have several DR$ tables in my database. I think they come because I am using text indexes. This is third party application. When I run dbms_stats to do statistics on entire schema, it never calculates statistics on DR$ tables. Somewhere I had read that Oracle uses rule base optimizer , yes rule based optimizer for these tables. I am on Oracle 10.2.0.4. When I rebuild text indexes, it never computes statistics on these tables as well.
What is stage that some of my queries involving text indexes run slow that database control (database tuning advisor) is recommending run statistics on these tables!!! Can someone provide their thoughts on it?
You may want to review 'Performance Tuning' chapter in the Text Application Developer's Guide.
http://docs.oracle.com/cd/B12037_01/text.101/b10729/aoptim.htm
It discusses those tables and how to optimize the stats.
It will also tell you this:
7.1.1 Collecting Statistics
By default, Oracle Text uses the cost-based optimizer to determine the best execution plan for a query. To allow the optimizer to better estimate costs, you can calculate the statistics on the table you query. To do so, issue the following statement:
ANALYZE TABLE <table_name> COMPUTE STATISTICS;
Did you note that is says 'cost-based optimizer'?
As for those DR$ tables:
7.7.7 What tables are involved in queries?
Answer: All queries look at the index token table. Its name has the form DR$indexname$I. This contains the list of tokens (column TOKEN_TEXT) and the information about the row and word positions where the token occurs (column TOKEN_INFO).
The row information is stored as internal DOCID values. These must be translated into external ROWID values. The table used for this depends on the type of lookup: For functional lookups, the $K table, DR$indexname$K, is used. This is a simple Index Organized Table (IOT) which contains a row for each DOCID/ROWID pair.
For indexed lookups, the $R table, DR$indexname$R, is used. This holds the complete list of ROWIDs in a BLOB column.
Hence we can easily find out whether a functional or indexed lookup is being used by examining a SQL trace, and looking for the $K or $R tables.

Statistics on Partioned Table

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