Data Federator Full Table scan

Hi,
Is it possible to prevent a Full table scan when creating a join between tables of 2 catalogues in a Data Federator?
This is seriously hampering the development time within Data Federator Development.
I am working with IDT Beta to create a Universe based on Multiple Source. The delay is so huge when creating joins that we could revert to Universe Design Tool. I have posted it here as Data Federator gurus will have tweak about IDT as it incorporates DF within itself in BI 4.0.
Any inputs will be great.. In case this is in the wrong forums, then please move it accordingly.
VFernandes

The issue was fixed when the GA was released. This was present in Beta

Similar Messages

Prompt on DATE forces FULL TABLE SCAN

When using a prompt on a datetime field OBIEE sends a SQL to the Database with the TIMESTAMP COMMAND.
Due to Timestamp the Oracle database does a Full Table Scan. The field ATIST is a date with time on the physical database.
By Default ATIST was configured as TIMESTAMP in the rpd physical layer. The SQL request is sent to a Oracle 10 Database.
That is the query sent to the database:
-------------------- Sending query to database named PlantControl1 (id: <<10167>>):
select distinct T1471.ATIST as c1,
T1471.GUTMENGEMELD2 as c2
from
AGRUECK T1471 /* Fact_ARBEITSGANGMELDUNGEN */
where ( T1471.ATIST = TIMESTAMP '2005-04-01 13:48:05' )
order by c1, c2
The result takes more than half a minute to appear.
Because BIEE is using "TIMESTAMP" , the database performs a full table scan instead of using the index.
By using TO_DATE instead of timestamp the result appears after a second.
select distinct T1471.ATIST, T1471.GUTMENGEMELD2 as c2
from
AGRUECK T1471 /* Fact_ARBEITSGANGMELDUNGEN */
where ( T1471.ATIST = to_date('2005.04.01 13:48:05', 'yyyy.mm.dd hh24:mi:ss') );
Is there any way resolving the issue?
PS:When the field ATIST is configured as date at the physical layer the SQL performs well is it uses the command "to_date" instead of "timestamp". But this cuts the time of the date, When it is configured as DATETIME, OBIEE uses TIMESTAMP again.
What I need is a working date + time field.
Anybody has encountered a similiar problem?

To be honest I haven't come across many scenarios where the Time has been important. Most of our reporting stops at Day level.
What is the real world business question being asked here that requires DayTime?
Incidentally if you change your datatype on the base table you will see it works fine.
CREATE TABLE daytime( daytime TIMESTAMP );
CREATE UNIQUE INDEX dt ON daytime (daytime)
SQL> set autotrace traceonly
SQL> SELECT * FROM daytime
2 WHERE daytime = TIMESTAMP '2007-04-01 13:00:45';
no rows selected
Execution Plan
Plan hash value: 3985400340
| Id | Operation         | Name | Rows | Bytes | Cost (%CPU)| Time     |
|   0 | SELECT STATEMENT |      |     1 |    13 |     1   (0)| 00:00:01 |
|* 1 | INDEX UNIQUE SCAN| DT   |     1 |    13 |     1   (0)| 00:00:01 |
Predicate Information (identified by operation id):
   1 - access("DAYTIME"=TIMESTAMP' 2007-04-01 13:00:45.000000000')
Statistics
          1 recursive calls
          0 db block gets
          1 consistent gets
          0 physical reads
          0 redo size
        242 bytes sent via SQL*Net to client
        362 bytes received via SQL*Net from client
          1 SQL*Net roundtrips to/from client
          0 sorts (memory)
          0 sorts (disk)
          0 rows processed
SQL>However if its a date it would appear to do some internal function call which I guess is the source of the problem ...
| Id | Operation         | Name    | Rows | Bytes | Cost (%CPU)| Time     |
|   0 | SELECT STATEMENT |         |     1 |     9 |     2   (0)| 00:00:01 |
|* 1 | TABLE ACCESS FULL| DAYTIME |     1 |     9 |     2   (0)| 00:00:01 |
Predicate Information (identified by operation id):
   1 - filter(INTERNAL_FUNCTION("DAYTIME")=TIMESTAMP' 2007-04-01
              13:00:45.000000000')

Select statement in a function does Full Table Scan

All,
I have been coding a stored procedure that writes 38K rows in less than a minute. If I add another column which requires call to a package and 4 functions within that package, it runs for about 4 hours. I have confirmed that due to problems in one of the functions, the code does full table scans. The package and all of its functions were written by other contractors who have been long gone.
Please note that case_number_in (VARCHAR2) and effective_date_in (DATE) are parameters sent to the problem function and I have verified through TOAD’s debugger that their values are correct.
Table named ps2_benefit_register has over 40 million rows but case_number is an index for that table.
Table named ps1_case_fs has more than 20 million rows but also uses case_number as an index.
Select #1 – causes full table scan runs and writes 38K rows in a couple of hours.
{case}
SELECT max(a2.application_date)
INTO l_app_date
FROM dwfssd.ps2_benefit_register a1, dwfssd.ps2_case_fs a2
WHERE a2.case_number = case_number_in and
a1.case_number = a2.case_number and
a2.application_date <= effective_date_in and
a1.DOCUMENT_TYPE = 'F';
{case}
Select #2 – runs – hard coding values makes the code to write the same 38K rows in a few minutes.
{case}
SELECT max(a2.application_date)
INTO l_app_date
FROM dwfssd.ps2_benefit_register a1, dwfssd.ps2_case_fs a2
WHERE a2.case_number = 'A006438' and
a1.case_number = a2.case_number and
a2.application_date <= '01-Apr-2009' and
a1.DOCUMENT_TYPE = 'F';
{case}
Why using the values in the passed parameter in the first select statement causes full table scan?
Thank you for your help,
Seyed
Edited by: user11117178 on Jul 30, 2009 6:22 AM
Edited by: user11117178 on Jul 30, 2009 6:23 AM
Edited by: user11117178 on Jul 30, 2009 6:24 AM

Hello Dan,
Thank you for your input. The function is not determinsitic, therefore, I am providing you with the explain plan. By version number, if you are refering to the Database version, we are running 10g.
PLAN_TABLE_OUTPUT
Plan hash value: 2132048964
| Id | Operation                     | Name                    | Rows | Bytes | Cost (%CPU)| Time     | Pstart| Pstop |
|   0 | SELECT STATEMENT              |                         |   324K|    33M| 3138   (5)| 00:00:38 |       |       |
|* 1 | HASH JOIN                    |                         |   324K|    33M| 3138   (5)| 00:00:38 |       |       |
|   2 |   BITMAP CONVERSION TO ROWIDS |                         |     3 |     9 |     1   (0)| 00:00:01 |       |       |
|* 3 |    BITMAP INDEX FAST FULL SCAN| IDX_PS2_ACTION_TYPES    |       |       |            |          |       |       |
|   4 |   PARTITION RANGE ITERATOR    |                         |   866K|    87M| 3121   (4)| 00:00:38 |   154 |   158 |
|   5 |    TABLE ACCESS FULL          | PS2_FS_TRANSACTION_FACT |   866K|    87M| 3121   (4)| 00:00:38 |   154 |   158 |
Predicate Information (identified by operation id):
   1 - access("AL1"."ACTION_TYPE_ID"="AL2"."ACTION_TYPE_ID")
   3 - filter("AL2"."ACTION_TYPE"='1' OR "AL2"."ACTION_TYPE"='2' OR "AL2"."ACTION_TYPE"='S')
Thank you very much,
Seyed

URGENT HELP Required: Solution to avoid Full table scan for a PL/SQL query

Hi Everyone,
When I checked the EXPLAIN PLAN for the below SQL query, I saw that Full table scans is going on both the tables TABLE_A and TABLE_B
UPDATE TABLE_A a
SET a.current_commit_date =
(SELECT MAX (b.loading_date)
FROM TABLE_B b
WHERE a.sales_order_id = b.sales_order_id
AND a.sales_order_line_id = b.sales_order_line_id
AND b.confirmed_qty > 0
AND b.data_flag IS NULL
OR b.schedule_line_delivery_date >= '23 NOV 2008')
Though the TABLE_A is a small table having nearly 1 lakh records, the TABLE_B is a huge table, having nearly 2 and a half crore records.
I created an Index on the TABLE_B having all its fields used in the WHERE clause. But, still the explain plan is showing FULL TABLE SCAN only.
When I run the query, it is taking long long time to execute (more than 1 day) and each time I have to kill the session.
Please please help me in optimizing this.
Thanks,
Sudhindra

Check the instruction again, you're leaving out information we need in order to help you, like optimizer information.
- Post your exact database version, that is: the result of select * from v$version;
- Don't use TOAD's execution plan, but use
SQL> explain plan for <your_query>;
SQL> select * from table(dbms_xplan.display);(You can execute that in TOAD as well).
Don't forget you need to use the {noformat}{noformat} tag in order to post formatted code/output/execution plans etc.
It's also explained in the instruction.
When was the last time statistics were gathered for table_a and table_b?
You can find out by issuing the following query:select table_name
, last_analyzed
, num_rows
from user_tables
where table_name in ('TABLE_A', 'TABLE_B');
Can you also post the results of these counts;select count(*)
from table_b
where confirmed_qty > 0;
select count(*)
from table_b
where data_flag is null;
select count(*)
from table_b
where schedule_line_delivery_date >= /* assuming you're using a date, and not a string*/ to_date('23 NOV 2008', 'dd mon yyyy');

How to avoid full Table scan when using Rule based optimizer (Oracle817)

1. We have a Oracle 8.1.7 DB, and the optimizer_mode is set to "RULE"
2. There are three indexes on table cm_contract_supply, which is a large table having 28732830 Rows, and average row length 149 Bytes
COLUMN_NAME INDEX_NAME
PROGRESS_RECID XAK11CM_CONTRACT_SUPPLY
COMPANY_CODE XIE1CM_CONTRACT_SUPPLY
CONTRACT_NUMBER XIE1CM_CONTRACT_SUPPLY
COUNTRY_CODE XIE1CM_CONTRACT_SUPPLY
SUPPLY_TYPE_CODE XIE1CM_CONTRACT_SUPPLY
VERSION_NUMBER XIE1CM_CONTRACT_SUPPLY
CAMPAIGN_CODE XIF1290CM_CONTRACT_SUPPLY
COMPANY_CODE XIF1290CM_CONTRACT_SUPPLY
COUNTRY_CODE XIF1290CM_CONTRACT_SUPPLY
SUPPLIER_BP_ID XIF801CONTRACT_SUPPLY
COMMISSION_LETTER_CODE XIF803CONTRACT_SUPPLY
COMPANY_CODE XIF803CONTRACT_SUPPLY
COUNTRY_CODE XIF803CONTRACT_SUPPLY
COMPANY_CODE XPKCM_CONTRACT_SUPPLY
CONTRACT_NUMBER XPKCM_CONTRACT_SUPPLY
COUNTRY_CODE XPKCM_CONTRACT_SUPPLY
SUPPLY_SEQUENCE_NUMBER XPKCM_CONTRACT_SUPPLY
VERSION_NUMBER XPKCM_CONTRACT_SUPPLY
3. We are querying the table for a particular contract_number and version_number. We want to avoid full table scan.
SELECT /*+ INDEX(XAK11CM_CONTRACT_SUPPLY) */
rowid, pms.cm_contract_supply.*
FROM pms.cm_contract_supply
WHERE
contract_number = '0000000000131710'
AND version_number = 3;
However despite of giving hint, query results are fetched after full table scan.
Execution Plan
0 SELECT STATEMENT Optimizer=RULE (Cost=1182 Card=1 Bytes=742)
1 0 TABLE ACCESS (FULL) OF 'CM_CONTRACT_SUPPLY' (Cost=1182 Card=1 Bytes=742)
4. I have tried giving
SELECT /*+ FIRST_ROWS + INDEX(XAK11CM_CONTRACT_SUPPLY) */
rowid, pms.cm_contract_supply.*
FROM pms.cm_contract_supply
WHERE
contract_number = '0000000000131710'
AND version_number = 3;
and
SELECT /*+ CHOOSE + INDEX(XAK11CM_CONTRACT_SUPPLY) */
rowid, pms.cm_contract_supply.*
FROM pms.cm_contract_supply
WHERE
contract_number = '0000000000131710'
AND version_number = 3;
But it does not work.
Is there some way without changing optimizer mode and without creating an additional index, we can use the index instead of full table scan?

David,
Here is my test on a Oracle 10g database.
SQL> create table mytable as select * from all_tables;
Table created.
SQL> set autot traceonly
SQL> alter session set optimizer_mode = choose;
Session altered.
SQL> select count(*) from mytable;
Execution Plan
   0      SELECT STATEMENT Optimizer=CHOOSE
   1    0   SORT (AGGREGATE)
   2    1     TABLE ACCESS (FULL) OF 'MYTABLE' (TABLE)
Statistics
          1 recursive calls
          0 db block gets
         29 consistent gets
          0 physical reads
          0 redo size
        223 bytes sent via SQL*Net to client
        276 bytes received via SQL*Net from client
          2 SQL*Net roundtrips to/from client
          0 sorts (memory)
          0 sorts (disk)
          1 rows processed
SQL> analyze table mytable compute statistics;
Table analyzed.
SQL> select count(*) from mytable
2 ;
Execution Plan
   0      SELECT STATEMENT Optimizer=CHOOSE (Cost=11 Card=1)
   1    0   SORT (AGGREGATE)
   2    1     TABLE ACCESS (FULL) OF 'MYTABLE' (TABLE) (Cost=11 Card=1
          788)
Statistics
          1 recursive calls
          0 db block gets
         29 consistent gets
          0 physical reads
          0 redo size
        222 bytes sent via SQL*Net to client
        276 bytes received via SQL*Net from client
          2 SQL*Net roundtrips to/from client
          0 sorts (memory)
          0 sorts (disk)
          1 rows processed
SQL> disconnect
Disconnected from Oracle Database 10g Enterprise Edition Release 10.1.0.2.0 - 64bit Production
With the Partitioning, Oracle Label Security, OLAP and Data Mining options

Slow queries and full table scans in spite of context index

I have defined a USER_DATASTORE, which uses a PL/SQL procedure to compile data from several tables. The master table has 1.3 million rows, and one of the fields being joined is a CLOB field.
The resulting token table has 65,000 rows, which seems about right.
If I query the token table for a word, such as "ORACLE" in the token_text field, I see that the token_count is 139. This query returns instantly.
The query against the master table is very slow, taking about 15 minutes to return the 139 rows.
Example query:
select hnd from master_table where contains(myindex,'ORACLE',1) > 0;
I've run a sql_trace on this query, and it shows full table scans on both the master table and the DR$MYINDEX$I table. Why is it doing this, and how can I fix it?

After looking at the tuning FAQ, I can see that this is doing a functional lookup instead of an indexed lookup. But why, when the rows are not constrained by any structural query, and how can I get it to instead to an indexed lookup?
Thanks in advance,
Annie

Simple Query in Oracle Linked Table in MS Access causes full table scan.

I am running a very simple query in MS ACCESS to a linked Oracle table as follows:
Select *
From EXPRESS_SERVICE_EVENTS --(the linked table name refers to EXPRESS.SERVICE_EVENTS)
Where performed > MyDate()
or
Select *
From EXPRESS_SERVICE_EVENTS --(the linked table name refers to EXPRESS.SERVICE_EVENTS)
Where performed > [Forms]![MyForm]![Date1]
We have over 50 machines and this query runs fine on over half of these, using an Oracle Index on the "performed" field. Running exactly the same thing on the other machines causes a full table scan, therefore ignoring the Index (all machines access the same Access DB).
Strangely, if we write the query as follows:
Select *
From EXPRESS_SERVICE_EVENTS
Where performed > #09/04/2009 08:00#
it works fast everywhere!
Any help on this 'phenominon' would be appreciated.
Things we've done:
Checked regional settings, ODBC driver settings, MS Access settings (as in Tools->Options), we have the latest XP and Office service packs, and re-linked all Access Tables on both the slow and fast machines independantly).

Primarily, thanks gdarling for your reply. This solved our problem.
Just a small note to those who may be using this thread.
Although this might not be the reason, my PC had Oracle 9iR2 installed with Administratiev Tools, where user machines had the same thing installed but using Runtime Installation. For some reason, my PC did not have 'bind date' etc. as an option in the workarounds, but user machines did have this workaround option. Strangely, although I did not have the option, my (ODBC) query was running as expected, but user queries were not.
When we set the workaround checkbox accordingly, the queries then run as expected (fast).
Once again,
Thanks

Taking more time in INDEX RANGE SCAN compare to the full table scan

Hi all ,
Below are the version og my database.
SQL> select * from v$version;
BANNER
Oracle Database 10g Enterprise Edition Release 10.2.0.4.0 - 64bi
PL/SQL Release 10.2.0.4.0 - Production
CORE 10.2.0.4.0 Production
TNS for HPUX: Version 10.2.0.4.0 - Production
NLSRTL Version 10.2.0.4.0 - Production
I have gather the table statistics and plan change for sql statment.
SELECT P1.COMPANY, P1.PAYGROUP, P1.PAY_END_DT, P1.PAYCHECK_OPTION,
P1.OFF_CYCLE, P1.PAGE_NUM, P1.LINE_NUM, P1.SEPCHK FROM PS_PAY_CHECK P1
WHERE P1.FORM_ID = :1 AND P1.PAYCHECK_NBR = :2 AND
P1.CHECK_DT = :3 AND P1.PAYCHECK_OPTION <> 'R'
Plan before the gather stats.
Plan hash value: 3872726522
| Id | Operation         | Name         | Rows | Bytes | Cost (%CPU)| Time     |
|   0 | SELECT STATEMENT |              |       |       | *14306* (100)|          |
|   1 | *TABLE ACCESS FULL| PS_PAY_CHECK* |     1 |    51 | 14306   (4)| 00:02:52 |
Plan after the gather stats:
Operation     Object Name     Rows     Bytes     Cost
SELECT STATEMENT Optimizer Mode=CHOOSE
          1           4
*TABLE ACCESS BY INDEX ROWID     SYSADM.PS_PAY_CHECK*     1     51     *4*
    *INDEX RANGE SCAN     SYSADM.PS0PAY_CHECK*     1           3After gather stats paln look good . but when i am exeuting the query it take 5 hours. before the gather stats it finishing the within 2 hours. i do not want to restore my old statistics. below are the data for the tables.and when i am obserrving it lot of db files scatter rea
NAME                                 TYPE        VALUE
_optimizer_cost_based_transformation string      OFF
filesystemio_options                 string      asynch
object_cache_optimal_size            integer     102400
optimizer_dynamic_sampling           integer     2
optimizer_features_enable            string      10.2.0.4
optimizer_index_caching              integer     0
optimizer_index_cost_adj             integer     100
optimizer_mode                       string      choose
optimizer_secure_view_merging        boolean     TRUE
plsql_optimize_level                 integer     2
SQL> select count(*) from sysadm.ps_pay_check;
select num_rows,blocks from dba_tables where table_name ='PS_PAY_CHECK';
COUNT(*)
   1270052
SQL> SQL> SQL>
NUM_ROWS     BLOCKS
   1270047      63166
Event                                 Waits    Time (s)   (ms)   Time Wait Class
db file sequential read           1,584,677       6,375      4   36.6   User I/O
db file scattered read            2,366,398       5,689      2   32.7   User I/Oplease let me know why it taking more time in INDEX RANGE SCAN compare to the full table scan?

suresh.ratnaji wrote:
NAME                                 TYPE        VALUE
_optimizer_cost_based_transformation string      OFF
filesystemio_options                 string      asynch
object_cache_optimal_size            integer     102400
optimizer_dynamic_sampling           integer     2
optimizer_features_enable            string      10.2.0.4
optimizer_index_caching              integer     0
optimizer_index_cost_adj             integer     100
optimizer_mode                       string      choose
optimizer_secure_view_merging        boolean     TRUE
plsql_optimize_level                 integer     2
please let me know why it taking more time in INDEX RANGE SCAN compare to the full table scan?Suresh,
Any particular reason why you have a non-default value for a hidden parameter, optimizercost_based_transformation ?
On my 10.2.0.1 database, its default value is "linear". What happens when you reset the value of the hidden parameter to default?

Trunc causing Full Table Scans

I have a situtaion here where my query is as follows.
SQL> select count(1) from HBSM_SM_ACCOUNT_INFO where OPTIONAL_PARM5='MH' and CUST_STATUS in ('UP','UUP') and trunc(FIRST_ACTVN_DATE) = trunc(sysdate);
COUNT(1)
6
PLAN_TABLE_OUTPUT
Plan hash value: 3951750498
| Id | Operation | Name | Rows | Bytes | Cost (%CPU)| Time | Pstart| Pstop |
| 0 | SELECT STATEMENT | | 1 | 10 | 13904 (1)| 00:02:47 | | |
| 1 | SORT AGGREGATE | | 1 | 10 | | | | |
| 2 | PARTITION LIST SINGLE| | 1 | 10 | 13904 (1)| 00:02:47 | 12 | 12 |
|* 3 | TABLE ACCESS FULL | HBSM_SM_ACCOUNT_INFO | 1 | 10 | 13904 (1)| 00:02:47 | 12 | 12 |
Predicate Information (identified by operation id):
3 - filter(("CUST_STATUS"='UP' OR "CUST_STATUS"='UUP') AND
TO_DATE(INTERNAL_FUNCTION("FIRST_ACTVN_DATE"))=TO_DATE(TO_CHAR(SYSDATE@!)))
16 rows selected.
If I remove the trunc clause from the query the performance definitely improves the the results are wrong.
SQL> select count(1) from HBSM_SM_ACCOUNT_INFO where OPTIONAL_PARM5='MH' and CUST_STATUS in ('UP','UUP') and FIRST_ACTVN_DATE = trunc(sysdate);
COUNT(1)
0
PLAN_TABLE_OUTPUT
Plan hash value: 454529511
| Id | Operation | Name | Rows | Bytes | Cost (%CPU)| Time | Pstart| Pstop |
| 0 | SELECT STATEMENT | | 1 | 40 | 47 (0)| 00:00:01 | | |
|* 1 | TABLE ACCESS BY GLOBAL INDEX ROWID| HBSM_SM_ACCOUNT_INFO | 1 | 40 | 47 (0)| 00:00:01 | 12 | 12 |
|* 2 | INDEX RANGE SCAN | IND_FIRST_ACTVN_DATE | 51 | | 4 (0)| 00:00:01 | | |
Can someone please help me whereby I can get the right data and I can also prevent these full table scans.

Unless you are using a functional index, applying any function to an indexed column prevents the use of the index.
The way round it in your case is to realise that
select count(1) from HBSM_SM_ACCOUNT_INFO where OPTIONAL_PARM5='MH' and CUST_STATUS in ('UP','UUP') and trunc(FIRST_ACTVN_DATE) = trunc(sysdate)Is really asking that FIRST_ACTVN_DATE should be sometime today. You could therefore rewrite it as
select count(1) from HBSM_SM_ACCOUNT_INFO where OPTIONAL_PARM5='MH' and CUST_STATUS in ('UP','UUP')
and FIRST_ACTVN_DATE >= trunc(sysdate)
and FIRST_ACTVN_DATE < trunc(sysdate) + 1Note, this still might not use the index depending on how many rows are within today's date versus how many are outside today's date.
Also, when posting, remember to put your code between tags and to post create table scripts and sample data inserts.

Why does not a query go by index but FULL TABLE SCAN

I have two tables;
table 1 has 1400 rwos and more than 30 columns , one of them is named as 'site_code' , a index was created on this column;
table 2 has more 150 rows than 20 column , this primary key is 'site_code' also.
the two tables were analysed by dbms_stats.gather_table()...
when I run the explain for the 2 sqls below:
select * from table1 where site_code='XXXXXXXXXX';
select * from table1 where site_code='XXXXXXXXXX';
certainly the oracle explain report show that 'Index scan'
but the problem raised that
I try to explain the sql
select *
from table1,table2
where 1.'site_code'=2.'site_code'
the explain report that :
select .....
FULL Table1 Scan
FULL Table2 Scan
why......

Nikolay Ivankin wrote:
BluShadow wrote:
Nikolay Ivankin wrote:
Try to use hint, but I really doubt it will be faster.No, using hints should only be advised when investigating an issue, not recommended for production code, as it assumes that, as a developer, you know better than the Oracle Optimizer how the data is distributed in the data files, and how the data is going to grow and change over time, and how best to access that data for performance etc.Yes, you are absolutly right. But aren't we performing such an investigation, are we? ;-)The way you wrote it, made it sound that a hint would be the solution, not just something for investigation.
select * from .. always performs full scan, so limit your query.No, select * will not always perform a full scan, that's just selecting all the columns.
A select without a where clause or that has a where clause that has low selectivity will result in full table scans.But this is what I have ment.But not what you said.

How to find the count of tables going for fts(full table scan in oracle 10g

HI
how to find the count of tables going for fts(full table scan) in oracle 10g
regards

Hi,
Why do you want to 'find' those tables?
Do you want to 'avoid FTS' on those tables?
You provide little information here. (Perhaps you just migrated from 9i and having problems with certain queries now?)
FTS is sometimes the fastest way to retrieve data, and sometimes an index scan is.
http://asktom.oracle.com/pls/asktom/f?p=100:11:0::::P11_QUESTION_ID:9422487749968
There's no 'FTS view' available, if you want to know what happens on your DB you need, like Anand already said, to trace sessions that 'worry you'.

Does Table Statistics collection have any effect on Full Table scan

We are using SQL Parallelism in Oracle 10g 10.2.0.4 (3 node RAC ).Most of the the big tables are going for FTS.
And these Table are truncated and loaded inside procedures and then used in next procedures in SELECT query.
As there is no stats or stale STATS available , does this affect the FTS performance.

Well, typically, it's a good idea to have up to date stats on your tables, so that the Optimiser has an idea what data is in the tables and can determine if an index or a full table scan is the best method of access. It doesn't necessarily remove full table scans, and a FTS is not necessarily a bad thing, but having up to date stats let's the optimiser choose what's best, based on the data, rather than making a wrong decision.

Slow query due to large table and full table scan

Hi,
We have a large Oracle database, v 10g. Two of the tables in the database have over one million rows.
We have a few queries which take a lot of time to execute. Not always though, it that seems when load is high the queries tend
to take much longer. Average time may be 1 or 2 seconds, but maxtime can be up to 2 minutes.
We have now used Oracle Grid to help us examine the queries. We have found that some of the queries require two or three full table scans.
Two of the full table scans are of the two large tables mentioned above.
This is an example query:
SELECT table1.column, table2.column, table3.column
FROM table1
JOIN table2 on table1.table2Id = table2.id
LEFT JOIN table3 on table2.table3id = table3.id
WHERE table1.id IN(
SELECT id
FROM (
(SELECT a.*, rownum rnum FROM(
SELECT table1.id
FROM table1,
table2,
table3
WHERE
table1.table2id = table2.id
AND
table2.table3id IS NULL OR table2.table3id = :table3IdParameter
) a
WHERE rownum <= :end))
WHERE rnum >= :start
Table1 and table2 are the large tables in this example. This query starts two full table scans on those tables.
Can we avoid this? We have, what we think are, the correct indexes.
/best regards, Håkan

>
Hi Håkan - welcome to the forum.
We have a large Oracle database, v 10g. Two of the tables in the database have over one million rows.
We have a few queries which take a lot of time to execute. Not always though, it that seems when load is high the queries tend
to take much longer. Average time may be 1 or 2 seconds, but maxtime can be up to 2 minutes.
We have now used Oracle Grid to help us examine the queries. We have found that some of the queries require two or three full table scans.
Two of the full table scans are of the two large tables mentioned above.
This is an example query:Firstly, please read the forum FAQ - top right of page.
Please format your SQL using tags [code /code].
In order to help us to help you.
Please post table structures - relevant (i.e. joined, FK, PK fields only) in the form - note use of code tags - we can just run table create script.
CREATE TABLE table1
Field1 Type1,
Field2 Type2,
FieldN TypeN
);Then give us some table data - not 100's of records - just enough in the form
INSERT INTO Table1 VALUES(Field1, Field2.... FieldN);
..Please post EXPLAIN PLAN - again with tags.
HTH,
Paul...
/best regards, Håkan

Query is doing full table scan

Hi All,
The below query is doing full table scan. So many threads from application trigger this query and doing full table scan. Can you please tell me how to improve the performance of this query?
Env is 11.2.0.3 RAC (4 node). Unique index on VZ_ID, LOGGED_IN. The table row count is 2,501,103.
Query is :-
select ccagentsta0_.LOGGED_IN as LOGGED1_404_, ccagentsta0_.VZ_ID as VZ2_404_, ccagentsta0_.ACTIVE as ACTIVE404_, ccagentsta0_.AGENT_STATE as AGENT4_404_,
ccagentsta0_.APPLICATION_CODE as APPLICAT5_404_, ccagentsta0_.CREATED_ON as CREATED6_404_, ccagentsta0_.CURRENT_ORDER as CURRENT7_404_,
ccagentsta0_.CURRENT_TASK as CURRENT8_404_, ccagentsta0_.HELM_ID as HELM9_404_, ccagentsta0_.LAST_UPDATED as LAST10_404_, ccagentsta0_.LOCATION as LOCATION404_,
ccagentsta0_.LOGGED_OUT as LOGGED12_404_, ccagentsta0_.SUPERVISOR_VZID as SUPERVISOR13_404_, ccagentsta0_.VENDOR_NAME as VENDOR14_404_
from AGENT_STATE ccagentsta0_ where ccagentsta0_.VZ_ID='v790531' and ccagentsta0_.ACTIVE='Y';
Table Scan                                                       AGENT_STATE                                                2.366666667
Table Scan                                                       AGENT_STATE                                                0.3666666667
Table Scan                                                       AGENT_STATE                                                1.633333333
Table Scan                                                       AGENT_STATE                                                       0.75
Table Scan                                                       AGENT_STATE                                                1.866666667
Table Scan                                                       AGENT_STATE                                                2.533333333
Table Scan                                                       AGENT_STATE                                                0.5333333333
Table Scan                                                       AGENT_STATE                                                       1.95
Table Scan                                                       AGENT_STATE                                                        0.8
Table Scan                                                       AGENT_STATE                                                0.2833333333
Table Scan                                                       AGENT_STATE                                                1.983333333
Table Scan                                                       AGENT_STATE                                                        2.5
Table Scan                                                       AGENT_STATE                                                1.866666667
Table Scan                                                       AGENT_STATE                                                1.883333333
Table Scan                                                       AGENT_STATE                                                        0.9
Table Scan                                                       AGENT_STATE                                                2.366666667
But the explain plan shows the query is taking the index
Explain plan output:-
PLAN_TABLE_OUTPUT
Plan hash value: 1946142815
| Id | Operation                   | Name            | Rows | Bytes | Cost (%C
PU)| Time     |
PLAN_TABLE_OUTPUT
|   0 | SELECT STATEMENT            |                 |     1 |   106 |   244
(0)| 00:00:03 |
|* 1 | TABLE ACCESS BY INDEX ROWID| AGENT_STATE     |     1 |   106 |   244
(0)| 00:00:03 |
|* 2 |   INDEX RANGE SCAN          | AGENT_STATE_IDX |   229 |       |     4
(0)| 00:00:01 |
PLAN_TABLE_OUTPUT
Predicate Information (identified by operation id):
   1 - filter("CCAGENTSTA0_"."ACTIVE"='Y')
   2 - access("CCAGENTSTA0_"."VZ_ID"='v790531')
The values (VZ_ID) i have given are dummy values picked from the table. I dont get the actual values since the query is coming with bind variables. Please let me know your suggestion on this.
Thanks,
Mani

Hi,
But I am not getting what is the issue..its a simple select query and index is there on one of the leading columns (VZ_ID --- PK). Explain plan says its using its using Index and it only select fraction of rows from the table. Then why it is doing FTS. For Optimizer, why its like a query doing FTS.
The rule-based optimizer would have picked the plan with the index. The cost-based optimizer, however, is picking the plan with the lowest cost. Apparently, the lowest cost plan is the one with the full table scan. And the optimizer isn't necessarily wrong about this.
Reading data from a table via index probes is only efficient when selecting a relatively small percentage of rows. For larger percentages, a full table scan is generally better.
Consider a simple example: a query that selects from a table with biographies for all people on the planet. Suppose you are interested in all people from a certain country.
select * from all_people where country='Vatican'
would only return only 800 rows (as Vatican is an extremely small country with population of just 800 people). For this case, obviously, using an index would be very efficient.
Now if we run this query:
select * from all_people where contry = 'India',
we'd be getting over a billion of rows. For this case, a full table scan would be several thousand times faster.
Now consider the third case:
select * from all_people where country = :b1
What plan should the optimizer choose? The value of :b1 bind variable is generally not known during the parse time, it will be passed by the user when the query is already parsed, during run-time.
In this case, one of two scenarios takes place: either the optimizer relies on some built-in default selectivities (basically, it takes a wild guess), or the optimizer postpones taking the final decision until the
first time the query is run, 'peeks' the value of the bind, and optimizes the query for this case.
In means, that if the first time the query is parsed, it was called with :b1 = 'India', a plan with a full table scan will be generated and cached for subsequent usage. And until the cursor is aged out of library cache
or invalidated for some reason, this will be the plan for this query.
If the first time it was called with :b1='Vatican', then an index-based plan will be picked.
Either way, bind peeking only gives good results if the subsequent usage of the query is the same kind as the first usage. I.e. in the first case it will be efficient, if the query would always be run for countries with big popultions.
And in the second case, if it's always run for countries with small populations.
This mechanism is called 'bind peeking' and it's one of the most common causes of performance problems. In 11g, there are more sophisticated mechanisms, such a cardinality feedback, but they don't always work as expected.
This mechanism is the most likely explanation for your issue. However, without proper diagnostic information we cannot be 100% sure.
Best regards,
Nikolay

Problem of full table scan on a partitioned table

hi all
There is a table called "si_sync_operation" that have 171040 number of rows.
I partitioned that table into a new table called "si_sync_operation_par" with 7 partitoins.
I issued the following statements
SELECT * FROM si_sync_operation_par.
SELECT * FROM si_sync_operation.
The explain plan show that the cost of the first statement is 1626 and that of the second statments is 1810.
The "cost" of full table scan on partitioned table is lower than the that of non-partitioned table.That's fine.
But the "Bytes" of full table scan on partitioned table is 5761288680 and that of the non-partitioned table is 263743680.
Why full table scan on partitioned table access more bytes than non-partitioned table?
And how could a statment that access more bytes results a lower cost?
Thank u very much

As Hemant metioned bytes reported are approximate number of bytes. As far as Cost is concerned, according to Tom its just a number and we should not compare queries by their cost. (search asktom.oracle.com for more information)
SQL> drop table non_part purge;
Table dropped.
SQL> drop table part purge;
Table dropped.
SQL>
SQL> CREATE TABLE non_part
2        (id NUMBER(5),
3         dt    DATE);
Table created.
SQL>
SQL> CREATE TABLE part
2        (id NUMBER(5),
3         dt    DATE)
4         PARTITION BY RANGE(dt)
5         (
6         PARTITION part1_jan2008 VALUES LESS THAN(TO_DATE('01/02/2008','DD/MM/YYYY')),
7         PARTITION part2_feb2008 VALUES LESS THAN(TO_DATE('01/03/2008','DD/MM/YYYY')),
8         PARTITION part3_mar2008 VALUES LESS THAN(TO_DATE('01/04/2008','DD/MM/YYYY')),
9         PARTITION part4_apr2008 VALUES LESS THAN(TO_DATE('01/05/2008','DD/MM/YYYY')),
10         PARTITION part5_may2008 VALUES LESS THAN(TO_DATE('01/06/2008','DD/MM/YYYY'))
11       );
Table created.
SQL>
SQL>
SQL> insert into non_part select rownum, trunc(sysdate) - rownum from dual connect by level <= 140;
140 rows created.
Execution Plan
Plan hash value: 1731520519
| Id | Operation                     | Name | Rows | Cost (%CPU)| Time     |
|   0 | INSERT STATEMENT              |      |     1 |     2   (0)| 00:00:01 |
|   1 | COUNT                        |      |       |            |          |
|* 2 |   CONNECT BY WITHOUT FILTERING|      |       |            |          |
|   3 |    FAST DUAL                  |      |     1 |     2   (0)| 00:00:01 |
Predicate Information (identified by operation id):
   2 - filter(LEVEL<=140)
SQL>
SQL> insert into part select * from non_part;
140 rows created.
Execution Plan
Plan hash value: 1654070669
| Id | Operation         | Name     | Rows | Bytes | Cost (%CPU)| Time     |
|   0 | INSERT STATEMENT |          |   140 | 3080 |     3   (0)| 00:00:01 |
|   1 | TABLE ACCESS FULL| NON_PART |   140 | 3080 |     3   (0)| 00:00:01 |
Note
   - dynamic sampling used for this statement
SQL>
SQL> commit;
Commit complete.
SQL>
SQL> set line 10000
SQL> set autotrace traceonly exp
SQL> select * from non_part;
Execution Plan
Plan hash value: 1654070669
| Id | Operation         | Name     | Rows | Bytes | Cost (%CPU)| Time     |
|   0 | SELECT STATEMENT |          |   140 | 3080 |     3   (0)| 00:00:01 |
|   1 | TABLE ACCESS FULL| NON_PART |   140 | 3080 |     3   (0)| 00:00:01 |
Note
   - dynamic sampling used for this statement
SQL> select * from part;
Execution Plan
Plan hash value: 3392317243
| Id | Operation           | Name | Rows | Bytes | Cost (%CPU)| Time     | Pstart| Pstop |
|   0 | SELECT STATEMENT    |      |   140 | 3080 |     9   (0)| 00:00:01 |       |       |
|   1 | PARTITION RANGE ALL|      |   140 | 3080 |     9   (0)| 00:00:01 |     1 |     5 |
|   2 |   TABLE ACCESS FULL | PART |   140 | 3080 |     9   (0)| 00:00:01 |     1 |     5 |
Note
   - dynamic sampling used for this statement
SQL>
SQL> exec dbms_stats.gather_table_stats(user, 'non_part');
PL/SQL procedure successfully completed.
SQL> exec dbms_stats.gather_table_stats(user, 'part');
PL/SQL procedure successfully completed.
SQL>
SQL>
SQL> select * from non_part;
Execution Plan
Plan hash value: 1654070669
| Id | Operation         | Name     | Rows | Bytes | Cost (%CPU)| Time     |
|   0 | SELECT STATEMENT |          |   140 | 1540 |     3   (0)| 00:00:01 |
|   1 | TABLE ACCESS FULL| NON_PART |   140 | 1540 |     3   (0)| 00:00:01 |
SQL> select * from part;
Execution Plan
Plan hash value: 3392317243
| Id | Operation           | Name | Rows | Bytes | Cost (%CPU)| Time     | Pstart| Pstop |
|   0 | SELECT STATEMENT    |      |   140 | 1540 |     9   (0)| 00:00:01 |       |       |
|   1 | PARTITION RANGE ALL|      |   140 | 1540 |     9   (0)| 00:00:01 |     1 |     5 |
|   2 |   TABLE ACCESS FULL | PART |   140 | 1540 |     9   (0)| 00:00:01 |     1 |     5 |
SQL>After analyzing the tables, notice that the Bytes column has changed value

Data Federator Full Table scan

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