Order by column has index which results in full table scan

I have a query on table A which has index for column B.In the query i am using order by column B .In explain plan it shows that the full table scan is performed for table A without picking up the index for B .How can i ensure that index is picked up in the explain plan.Please help its urgent.
Pandu

Please help its urgent.Contact Oracle Support in that case.
By making that remark you have just made Blushadow go out to lunch (again) now.... ;)
Depending on your query a full scan could be 100% appropriate here.
But since you didn't post your DB_version, optimizer settings, execution plan etc. there's not much more to say, really, besides:
"Full scans aren't always evil".
See:
[When your query takes too long...|http://forums.oracle.com/forums/thread.jspa?messageID=3299435]
[How to post a SQLstatement Tuning Request|http://forums.oracle.com/forums/thread.jspa?threadID=863295&tstart=0]

Similar Messages

Tables in subquery resulting in full table scans

Hi,
This is related to a p1 bug 13009447. Customer recently upgraded to 10G. Customer reported this type of problem for the second time.
Problem Description:
All the tables in sub-query are resulting in full table scans and hence are executing for hours.
Here is the query
SELECT /*+ PARALLEL*/
act.assignment_action_id
, act.assignment_id
, act.tax_unit_id
, as1.person_id
, as1.effective_start_date
, as1.primary_flag
FROM pay_payroll_actions pa1
, pay_population_ranges pop
, per_periods_of_service pos
, per_all_assignments_f as1
, pay_assignment_actions act
, pay_payroll_actions pa2
, pay_action_classifications pcl
, per_all_assignments_f as2
WHERE pa1.payroll_action_id = :b2
AND pa2.payroll_id = pa1.payroll_id
AND pa2.effective_date
BETWEEN pa1.start_date
AND pa1.effective_date
AND act.payroll_action_id = pa2.payroll_action_id
AND act.action_status IN ('C', 'S')
AND pcl.classification_name = :b3
AND pa2.consolidation_set_id = pa1.consolidation_set_id
AND pa2.action_type = pcl.action_type
AND nvl (pa2.future_process_mode, 'Y') = 'Y'
AND as1.assignment_id = act.assignment_id
AND pa1.effective_date
BETWEEN as1.effective_start_date
AND as1.effective_end_date
AND as2.assignment_id = act.assignment_id
AND pa2.effective_date
BETWEEN as2.effective_start_date
AND as2.effective_end_date
AND as2.payroll_id = as1.payroll_id
AND pos.period_of_service_id = as1.period_of_service_id
AND pop.payroll_action_id = :b2
AND pop.chunk_number = :b1
AND pos.person_id = pop.person_id
AND (
as1.payroll_id = pa1.payroll_id
OR pa1.payroll_id IS NULL
AND NOT EXISTS
SELECT /*+ PARALLEL*/ NULL
FROM pay_assignment_actions ac2
, pay_payroll_actions pa3
, pay_action_interlocks int
WHERE int.locked_action_id = act.assignment_action_id
AND ac2.assignment_action_id = int.locking_action_id
AND pa3.payroll_action_id = ac2.payroll_action_id
AND pa3.action_type IN ('P', 'U')
AND NOT EXISTS
SELECT /*+ PARALLEL*/
NULL
FROM per_all_assignments_f as3
, pay_assignment_actions ac3
WHERE :b4 = 'N'
AND ac3.payroll_action_id = pa2.payroll_action_id
AND ac3.action_status NOT IN ('C', 'S')
AND as3.assignment_id = ac3.assignment_id
AND pa2.effective_date
BETWEEN as3.effective_start_date
AND as3.effective_end_date
AND as3.person_id = as2.person_id
ORDER BY as1.person_id
, as1.primary_flag DESC
, as1.effective_start_date
, act.assignment_id
FOR UPDATE OF as1.assignment_id
, pos.period_of_service_id
Here is the execution plan for this query. We tried adding hints in sub-query to force indexes to pick-up but it is still doing Full table scans.
Suspecting some db parameter which is causing this issue.
In the
- Full table scans on tables in the first sub-query
PAY_PAYROLL_ACTIONS, PAY_ASSIGNMENT_ACTIONS, PAY_ACTION_INTERLOCKS
- Full table scans on tables in Second sub-query
PER_ALL_ASSIGNMENTS_F PAY_ASSIGNMENT_ACTIONS
call count cpu elapsed disk query current rows
Parse 1 0.00 0.00 0 0 0 0
Execute 29 398.80 2192.99 238706 4991924 2383 0
Fetch 1136 378.38 1921.39 0 4820511 0 1108
total 1166 777.19 4114.38 238706 9812435 2383 1108
Misses in library cache during parse: 1
Misses in library cache during execute: 1
Optimizer mode: ALL_ROWS
Parsing user id: 41 (APPS) (recursive depth: 1)
Rows Execution Plan
0 SELECT STATEMENT MODE: ALL_ROWS
0 FOR UPDATE
0 PX COORDINATOR
0 PX SEND (QC (ORDER)) OF ':TQ10009' [:Q1009]
0 SORT (ORDER BY) [:Q1009]
0 PX RECEIVE [:Q1009]
0 PX SEND (RANGE) OF ':TQ10008' [:Q1008]
0 HASH JOIN (ANTI BUFFERED) [:Q1008]
0 PX RECEIVE [:Q1008]
0 PX SEND (HASH) OF ':TQ10006' [:Q1006]
0 BUFFER (SORT) [:Q1006]
0 TABLE ACCESS MODE: ANALYZED (BY INDEX ROWID) OF 'PER_ALL_ASSIGNMENTS_F' (TABLE) [:Q1006]
0 NESTED LOOPS [:Q1006]
0 NESTED LOOPS [:Q1006]
0 NESTED LOOPS [:Q1006]
0 HASH JOIN (ANTI) [:Q1006]
0 BUFFER (SORT) [:Q1006]
0 PX RECEIVE [:Q1006]
0 PX SEND (HASH) OF ':TQ10002'
0 TABLE ACCESS MODE: ANALYZED (BY INDEX ROWID) OF 'PAY_ASSIGNMENT_ACTIONS' (TABLE)
0 NESTED LOOPS
0 NESTED LOOPS
0 NESTED LOOPS
0 NESTED LOOPS
0 TABLE ACCESS MODE: ANALYZED (BY INDEX ROWID) OF 'PAY_PAYROLL_ACTIONS' (TABLE)
0 INDEX MODE: ANALYZED (UNIQUE SCAN) OF 'PAY_PAYROLL_ACTIONS_PK' (INDEX (UNIQUE)
0 INDEX MODE: ANALYZED (RANGE SCAN) OF 'PAY_POPULATION_RANGES_N4' (INDEX)
0 TABLE ACCESS MODE: ANALYZED (BY INDEX ROWID) OF 'PER_PERIODS_OF_SERVICE' (TABLE)
0 INDEX MODE: ANALYZED (RANGE SCAN) OF 'PER_PERIODS_OF_SERVICE_N3' (INDEX)
0 TABLE ACCESS MODE: ANALYZED (BY INDEX ROWID) OF 'PER_ALL_ASSIGNMENTS_F' (TABLE)
0 INDEX MODE: ANALYZED (RANGE SCAN) OF 'PER_ASSIGNMENTS_N4' (INDEX)
0 INDEX MODE: ANALYZED (RANGE SCAN) OF 'PAY_ASSIGNMENT_ACTIONS_N51' (INDEX)
0 PX RECEIVE [:Q1006]
0 PX SEND (HASH) OF ':TQ10005' [:Q1005]
0 VIEW OF 'VW_SQ_1' (VIEW) [:Q1005]
0 HASH JOIN [:Q1005]
0 BUFFER (SORT) [:Q1005]
0 PX RECEIVE [:Q1005]
0 PX SEND (BROADCAST) OF ':TQ10000'
0 TABLE ACCESS MODE: ANALYZED (FULL) OF 'PAY_PAYROLL_ACTIONS' (TABLE)
0 HASH JOIN [:Q1005]
0 PX RECEIVE [:Q1005]
0 PX SEND (HASH) OF ':TQ10004' [:Q1004]
0 PX BLOCK (ITERATOR) [:Q1004]
0 TABLE ACCESS MODE: ANALYZED (FULL) OF 'PAY_ASSIGNMENT_ACTIONS' (TABLE) [:Q1004]
0 BUFFER (SORT) [:Q1005]
0 PX RECEIVE [:Q1005]
0 PX SEND (HASH) OF ':TQ10001'
0 TABLE ACCESS MODE: ANALYZED (FULL) OF 'PAY_ACTION_INTERLOCKS' (TABLE)
0 TABLE ACCESS MODE: ANALYZED (BY INDEX ROWID) OF 'PAY_PAYROLL_ACTIONS' (TABLE) [:Q1006]
0 INDEX MODE: ANALYZED (UNIQUE SCAN) OF 'PAY_PAYROLL_ACTIONS_PK' (INDEX (UNIQUE)) [:Q1006]
0 INDEX MODE: ANALYZED (UNIQUE SCAN) OF 'PAY_ACTION_CLASSIFICATIONS_PK' (INDEX (UNIQUE))[:Q1006]
0 INDEX MODE: ANALYZED (RANGE SCAN) OF 'PER_ASSIGNMENTS_F_PK' (INDEX (UNIQUE)) [:Q1006]
0 PX RECEIVE [:Q1008]
0 PX SEND (HASH) OF ':TQ10007' [:Q1007]
0 VIEW OF 'VW_SQ_2' (VIEW) [:Q1007]
0 FILTER [:Q1007]
0 HASH JOIN [:Q1007]
0 BUFFER (SORT) [:Q1007]
0 PX RECEIVE [:Q1007]
0 PX SEND (BROADCAST) OF ':TQ10003'
0 TABLE ACCESS MODE: ANALYZED (FULL) OF 'PER_ALL_ASSIGNMENTS_F' (TABLE)
0 PX BLOCK (ITERATOR) [:Q1007]
0 TABLE ACCESS MODE: ANALYZED (FULL) OF 'PAY_ASSIGNMENT_ACTIONS' (TABLE) [:Q1007]
Elapsed times include waiting on following events:
Event waited on Times Max. Wait Total Waited
---------------------------------------- Waited ---------- ------------
enq: KO - fast object checkpoint 32 0.02 0.12
os thread startup 8 0.02 0.19
PX Deq: Join ACK 198 0.00 0.04
PX Deq Credit: send blkd 167116 1.95 1103.72
PX Deq Credit: need buffer 327389 1.95 266.30
PX Deq: Parse Reply 148 0.01 0.03
PX Deq: Execute Reply 11531 1.95 1901.50
PX qref latch 23060 0.00 0.60
db file sequential read 108199 0.17 22.11
db file scattered read 9272 0.19 51.74
PX Deq: Table Q qref 78 0.00 0.03
PX Deq: Signal ACK 1165 0.10 10.84
enq: PS - contention 73 0.00 0.00
reliable message 27 0.00 0.00
latch free 218 0.00 0.01
latch: session allocation 11 0.00 0.00
Thanks in advance
Suresh PV

Hi,
welcome,
how is the query performing if you delete all the hints for PARALLEL, because most of the waits are related to waits on Parallel.
Herald ten Dam
http://htendam.wordpress.com
PS. Use "{code}" for showing your code and explain plans, it looks nicer

Why my query not using any index but doing a FULL TABLE SCAN

Hi,
My EXPLAIN PLAN output is
Plan hash value: 1163866984
| Id | Operation               | Name              | Rows | Bytes |TempSpc| Cost (%CPU)| Time     |
|   0 | SELECT STATEMENT        |                   |   774 |   159K|       | 40847   (2)| 00:08:11 |
|* 1 | FILTER                 |                   |       |       |       |            |          |
|   2 |   SORT GROUP BY         |                   |   774 |   159K|       | 40847   (2)| 00:08:11 |
|* 3 |    HASH JOIN            |                   | 77337 |    15M| 9744K| 40843   (2)| 00:08:11 |
|* 4 |     HASH JOIN           |                   | 77337 | 8836K| 5896K| 20987   (2)| 00:04:12 |
|* 5 |      HASH JOIN          |                   | 77337 | 4984K|       | 9292   (3)| 00:01:52 |
|* 6 |       HASH JOIN         |                   | 24991 |   951K|       | 3349   (3)| 00:00:41 |
|* 7 |        TABLE ACCESS FULL| IDS_TXNIDNUMBERS | 24991 |   683K|       | 2328   (3)| 00:00:28 |
|   8 |        TABLE ACCESS FULL| IDS_TXNDEMDATAMAP | 2419K|    25M|       | 1006   (3)| 00:00:13 |
|   9 |       TABLE ACCESS FULL | IDS_IDNUMBERS     | 7435K|   191M|       | 5903   (2)| 00:01:11 |
| 10 |      TABLE ACCESS FULL | IDS_DEMDATA       | 2583K|   125M|       | 3683   (5)| 00:00:45 |
| 11 |     TABLE ACCESS FULL   | IDS_TXN           | 2583K|   231M|       | 6403   (1)| 00:01:17 |
----------------------------------------------------------------------------------------------------- All my 5 tables IDS_TXNIDNUMBERS, IDS_TXNDEMDATAMAP, IDS_IDNUMBERS,IDS_DEMDATA, IDS_TXN has indexes in relevant columns. Is it cause less time so CBO is not using the indexes.
Thanks
Amitava.

amitavachatterjee1975 wrote:
Please be polite when responding to my queries. If you find these questions not to your standard, stay away from them. This is an open forum and I have got my full rights to ask questions.Unsure, what wrong did you find in SB's reply. I find those links perfectly knowledgeable. The question of having so many unanswered questions probably pricked you a little too much. But that, IMO, is a legitimate question, to be asked to a User who even after being associated with OTN for over an year has 100% record of not getting an answer.
For your original question, you will have to provide more details to allow people to answer you.
You must read {message:id=3292438} and post the mentioned details. People do not carry a Crystal Ball to identify the problem merely by reading few lines of Problem description and Explain plans. Do not make people guess, provide appropriate details, to help them Help "You".

Slow Query Using index. Fast with full table Scan.

Hi;
(Thanks for the links)
Here's my question correctly formated.
The query:
SELECT count(1)
from ehgeoconstru ec
where ec.TYPE='BAR'
AND ( ec.birthDate <= TO_DATE('2009-10-06 11:52:12', 'YYYY-MM-DD HH24:MI:SS') )
and deathdate is null
and substr(ec.strgfd, 1, length('[CIMText')) <> '[CIMText'Runs on 32 seconds!
Same query, but with one extra where clause:
SELECT count(1)
from ehgeoconstru ec
where ec.TYPE='BAR'
and ( (ec.contextVersion = 'REALWORLD')     --- ADDED HERE
AND ( ec.birthDate <= TO_DATE('2009-10-06 11:52:12', 'YYYY-MM-DD HH24:MI:SS') ) )
and deathdate is null
and substr(ec.strgfd, 1, length('[CIMText')) <> '[CIMText'This runs in 400 seconds.
It should return data from one table, given the conditions.
The version of the database is Oracle9i Release 9.2.0.7.0
These are the parameters relevant to the optimizer:
SQL> show parameter optimizer
NAME                                 TYPE        VALUE
optimizer_dynamic_sampling           integer     1
optimizer_features_enable            string      9.2.0
optimizer_index_caching              integer     99
optimizer_index_cost_adj             integer     10
optimizer_max_permutations           integer     2000
optimizer_mode                       string      CHOOSE
SQL> Here is the output of EXPLAIN PLAN for the first fast query:
PLAN_TABLE_OUTPUT
| Id | Operation                     | Name               | Rows | Bytes | Cost |
|   0 | SELECT STATEMENT     |                         |           |       |       |
|   1 | SORT AGGREGATE       |                         |           |       |       |
|* 2 |   TABLE ACCESS FULL   | EHCONS            |       |       |       |
Predicate Information (identified by operation id):
PLAN_TABLE_OUTPUT
   2 - filter(SUBSTR("EC"."strgfd",1,8)<>'[CIMText' AND "EC"."DEATHDATE"
              IS NULL AND "EC"."BIRTHDATE"<=TO_DATE('2009-10-06 11:52:12', 'yyyy
-mm-dd
              hh24:mi:ss') AND "EC"."TYPE"='BAR')
Note: rule based optimizationHere is the output of EXPLAIN PLAN for the slow query:
PLAN_TABLE_OUTPUT
   |       |
|   1 | SORT AGGREGATE              |                             |       |
   |       |
|* 2 |   TABLE ACCESS BY INDEX ROWID| ehgeoconstru      |       |
   |       |
|* 3 |    INDEX RANGE SCAN          | ehgeoconstru_VSN |       |
   |       |
PLAN_TABLE_OUTPUT
Predicate Information (identified by operation id):
2 - filter(SUBSTR("EC"."strgfd",1,8)<>'[CIMText' AND "EC"."DEATHDATE" IS
NULL AND "EC"."TYPE"='BAR')
PLAN_TABLE_OUTPUT
   3 - access("EC"."CONTEXTVERSION"='REALWORLD' AND "EC"."BIRTHDATE"<=TO_DATE('2
009-10-06
              11:52:12', 'yyyy-mm-dd hh24:mi:ss'))
       filter("EC"."BIRTHDATE"<=TO_DATE('2009-10-06 11:52:12', 'yyyy-mm-dd hh24:
mi:ss'))
Note: rule based optimizationThe TKPROF output for this slow statement is:
TKPROF: Release 9.2.0.7.0 - Production on Tue Nov 17 14:46:32 2009
Copyright (c) 1982, 2002, Oracle Corporation. All rights reserved.
Trace file: gen_ora_3120.trc
Sort options: prsela exeela fchela
count    = number of times OCI procedure was executed
cpu      = cpu time in seconds executing
elapsed = elapsed time in seconds executing
disk     = number of physical reads of buffers from disk
query    = number of buffers gotten for consistent read
current = number of buffers gotten in current mode (usually for update)
rows     = number of rows processed by the fetch or execute call
SELECT count(1)
from ehgeoconstru ec
where ec.TYPE='BAR'
and ( (ec.contextVersion = 'REALWORLD')
AND ( ec.birthDate <= TO_DATE('2009-10-06 11:52:12', 'YYYY-MM-DD HH24:MI:SS') ) )
and deathdate is null
and substr(ec.strgfd, 1, length('[CIMText')) <> '[CIMText'
call     count       cpu    elapsed       disk      query    current        rows
Parse        1      0.00       0.00          0          0          0           0
Execute      1      0.00       0.00          0          0          0           0
Fetch        2      0.00     538.12     162221    1355323          0           1
total        4      0.00     538.12     162221    1355323          0           1
Misses in library cache during parse: 0
Optimizer goal: CHOOSE
Parsing user id: 153
Rows     Row Source Operation
      1 SORT AGGREGATE
27747   TABLE ACCESS BY INDEX ROWID OBJ#(73959)
2134955    INDEX RANGE SCAN OBJ#(73962) (object id 73962)
alter session set sql_trace=true
call     count       cpu    elapsed       disk      query    current        rows
Parse        0      0.00       0.00          0          0          0           0
Execute      1      0.00       0.02          0          0          0           0
Fetch        0      0.00       0.00          0          0          0           0
total        1      0.00       0.02          0          0          0           0
Misses in library cache during parse: 0
Misses in library cache during execute: 1
Optimizer goal: CHOOSE
Parsing user id: 153
OVERALL TOTALS FOR ALL NON-RECURSIVE STATEMENTS
call     count       cpu    elapsed       disk      query    current        rows
Parse        1      0.00       0.00          0          0          0           0
Execute      2      0.00       0.02          0          0          0           0
Fetch        2      0.00     538.12     162221    1355323          0           1
total        5      0.00     538.15     162221    1355323          0           1
Misses in library cache during parse: 0
Misses in library cache during execute: 1
OVERALL TOTALS FOR ALL RECURSIVE STATEMENTS
call     count       cpu    elapsed       disk      query    current        rows
Parse        0      0.00       0.00          0          0          0           0
Execute      0      0.00       0.00          0          0          0           0
Fetch        0      0.00       0.00          0          0          0           0
total        0      0.00       0.00          0          0          0           0
Misses in library cache during parse: 0
    2 user SQL statements in session.
    0 internal SQL statements in session.
    2 SQL statements in session.
Trace file: gen_ora_3120.trc
Trace file compatibility: 9.02.00
Sort options: prsela exeela fchela
       2 sessions in tracefile.
       2 user SQL statements in trace file.
       0 internal SQL statements in trace file.
       2 SQL statements in trace file.
       2 unique SQL statements in trace file.
      94 lines in trace file.Edited by: PauloSMO on 17/Nov/2009 4:21
Edited by: PauloSMO on 17/Nov/2009 7:07
Edited by: PauloSMO on 17/Nov/2009 7:38 - Changed title to be more correct.

Although your optimizer_mode is choose, it appears that there are no statistics gathered on ehgeoconstru. The lack of cost estimate and estimated row counts from each step of the plan, and the "Note: rule based optimization" at the end of both plans would tend to confirm this.
Optimizer_mode choose means that if statistics are gathered then it will use the CBO, but if no statistics are present in any of the tables in the query, then the Rule Based Optimizer will be used. The RBO tends to be index happy at the best of times. I'm guessing that the index ehgeoconstru_VSN has contextversion as the leading column and also includes birthdate.
You can either gather statistics on the table (if all of the other tables have statistics) using dbms_stats.gather_table_stats, or hint the query to use a full scan instead of the index. Another alternative would be to apply a function or operation against the contextversion to preclude the use of the index. something like this:
SELECT COUNT(*)
FROM ehgeoconstru ec
WHERE ec.type='BAR' and
      ec.contextVersion||'' = 'REALWORLD'
      ec.birthDate <= TO_DATE('2009-10-06 11:52:12', 'YYYY-MM-DD HH24:MI:SS') and
      deathdate is null and
      SUBSTR(ec.strgfd, 1, LENGTH('[CIMText')) <> '[CIMText'or perhaps UPPER(ec.contextVersion) if that would not change the rows returned.
John

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.

Find out the SQLs which are using a full table scan

Hello all , how can i to find out the queries which are using a full table scan ? Any idea ?

In general, though, why would you want to tune SQL statements that aren't causing problems? Statspack will tell you what the most resource-intensive SQL statements on your system are. A SQL*Net trace of sessions that are performing poorly will indicate which statements are the most resource-intensive for that session. If a statement is incorrectly doing a full-table scan, but it is not causing a problem, why spend time tuning it? If you're not focusing your tuning attention on identifying statements that are causing problems, you'll also miss out on 90% of tuning opportunities which involve rewriting (or eliminating) code to make it more efficient. I can simulate a join on two tables with nested cursor loops, which won't generate a single full table scan, but replacing that code with a real join, while it will cause at least one full table scan, will be orders of magnitude faster.
As an aside, full table scans aren't necessarily a bad thing. If a statement needs to retrieve more than a couple percent of the rows of a table, full table scans are the most efficient way to go.
Justin
Distributed Database Consulting, Inc.
http://www.ddbcinc.com/askDDBC

Bitmap index column goes for full table scan

Hi all,
Database : 10g R2
OS : Windows xp
my select query is :
SELECT tran_id, city_id, valid_records
FROM transaction_details
WHERE type_id=101;
And the Explain Plan is :
Plan
SELECT STATEMENT ALL_ROWSCost: 29 Bytes: 8,876 Cardinality: 634
1 TABLE ACCESS FULL TABLE TRANSACTION_DETAILS** Cost: 29 Bytes: 8,876 Cardinality: 634
total number of rows in the table = 1800 ;
distinct value of type_ids are 101,102,103
so i created a bit map index on it.
CREATE BITMAP INDEX btmp_typeid ON transaction_details
(type_id)
LOGGING
NOPARALLEL;
after creating the index, the explain plan shows the same. why it goes for full table scan?.
Kindly share ur idea on this.
Edited by: 887268 on Apr 3, 2013 11:01 PM
Edited by: 887268 on Apr 3, 2013 11:02 PM

>
I am sorry for being ignorant, can you please cite any scenario of locking due to bitmap indices? A link can be useful as well.
>
See my full reply in this thread
Bitmap index for FKs on Fact tables
>
ETL is affected because DML operations (INSERT/UPDATE/DELETE) on tables with bitmapped indexes can have serious performance issues due to the serialization involved. Updating a single bit-mapped column value (e.g. from 'M' to 'F' for gender) requires both bitmapped index blocks to be locked until the update is complete. A bitmap index stored ROWID ranges (min rowid - max rowid) than can span many, many records. The entire 'range' of rowids is locked in order to change just one value.
To change from 'M' the 'M' rowid range for that one row is locked and the ROWID must be removed from the range byt clearing the bit. To change to 'F' the 'F' rowid id range needs to be found, locked and the bit set that corresponds to that rowid. No other rows with rowids in the range can be changed since this is a serial operation. If the range includes 1000 rows and they all need changed it takes 1000 serial operations.

Can we add a new column in report which is not in table.

Hi All,
Can we create a new column in report which is not in table.
I have two columns in my table completion_date, manufacture_date. If the difference between the completion_date and manufacture_date is 0, -1, 1 then the new column of the report will say on time against each record or else will display late. Any suggestion how to proceed on this
Regards
Edited by: User_Apex on May 16, 2011 5:54 AM

Standard report then, NOT an interactive report (which if you were using, you could build a computation and report on that)..
Then the adding a column in the query would be your best best...
Thank you,
Tony Miller
Webster, TX
There are two kinds of pedestrians -- the quick and the dead.
If this question is answered, please mark the thread as closed and assign points where earned..

Function based indexes doing full table scan

Guys,
I am testing function based indexes and whatever I do
it is doing a full table scan.
1)I have set the following init parameters as
QUERY_REWRITE_ENABLED=TRUE
QUERY_REWRITE_INTEGRITY=TRUSTED
2)CREATE INDEX i3 ON emp(UPPER(ename));
3) ANALYZE TABLE emp COMPUTE STATISTICS
ANALYZE INDEX I3 COMPUTE STATISTICS
4) DELETE plan_table;
5) EXPLAIN PLAN SET statement_id='Test1' FOR
SELECT ename FROM emp WHERE UPPER(ename) = 'KING';
6) SELECT LPAD(' ',2*level-2)||operation||' '||options||' '||object_name
query_plan
FROM plan_table
WHERE statement_id='Test1'
CONNECT BY prior id = parent_id
START WITH id = 0 order by id
7) And the query plan shows as
SELECT STATEMENT
TABLE ACCESS FULL EMP
I am using 9.0.1.4 !!!
Any help is appreciated !!!
Regards,
A.Kishore

One of the many new features in Oracle 8i is the Function-Based Index (we will refrain from using FBI, but only just). This allows the DBA to create indexes on functions or expressions; these functions can be user generated pl/sql functions, standard SQL functions (non-aggregate only) or even a C callout.
A classic problem the DBA faces in SQL Tuning is how to tune those queries that use function calls in the where clause, and result in indexes created on these columns not to be used.
Example
Standard B-Tree index on SURNAME with cost based optimizer
create index non_fbi on sale_contacts (surname);
analyze index non_fbi compute statistics;
analyze table sale_contacts compute statistics;
SELECT count(*) FROM sale_contacts
WHERE UPPER(surname) = 'ELLISON';
Execution Plan
0 SELECT STATEMENT Optimizer=CHOOSE (Cost=3 Card=1 Bytes=17)
1 0 SORT (AGGREGATE)
2 1 TABLE ACCESS (FULL) OF 'SALES_CONTACTS' (Cost=3 Card=16 Bytes=272)
Now we use a function based index
create index fbi on sale_contacts (UPPER(surname));
analyze index fbi compute statistics;
analyze table sale_contacts compute statistics;
SELECT count(*) FROM sale_contacts WHERE UPPER(surname) = 'ELLISON';
Execution Plan
0 SELECT STATEMENT Optimizer=CHOOSE (Cost=2 Card=1 Bytes=17)
1 0 SORT (AGGREGATE)
2 1 INDEX (RANGE SCAN) OF 'FBI' (NON-UNIQUE) (Cost=2 Card=381 Bytes=6477)
The function-based index has forced the optimizer to use index range scans (retuning zero or more rowids) on the surname column rather than doing a full table scan (non-index lookup). Optimal performance does vary depending on table size, uniqueness and selectivity of columns, use of fast full table scans etc. Therefore try both methods to gain optimal performance in your database.
It is important to remember that the function-based B*Tree index does not store the expression results in the index but uses an "expression tree". The optimizer performs expression matching by parsing the expression used in the SQL statement and comparing the results against the expression-tree values in the function-based index. This comparison IS case sensitive (ignores spaces) and therefore your function-based index expressions should match expressions used in the SQL statement where clauses.
Init.ora Parameters
The following parameter must be set in your parameter file: QUERY_REWRITE_INTEGRITY = TRUSTED
QUERY_REWRITE_ENABLED = TRUE
COMPATIBLE = 8.1.0.0.0 (or higher)
Grants
Grants To create function-based indexes the user must be granted CREATE INDEX and QUERY REWRITE, or alternatively be granted CREATE ANY INDEX and GLOBAL QUERY REWRITE. The index owner must have EXECUTE access on the function used for the index. If execute access is revoked then the function-based index will be "disabled" (see dba_indexes).
Disabled Indexes
If your function-based index has a status of "disabled" the DBA can do one of the following:
a) drop and create the index (take note of its current settings)
b) alter index enable, function-based indexes only, also use disable keyword as required
c) alter index unusable.
Queries on a DISABLED index fail if the optimizer chooses to use the index.Here is an example ORA error:
ERROR at line 1: ORA-30554: function-based index MYUSER.FBI is disabled.
All DML operations on a DISABLED index also fail unless the index is also marked UNUSABLE and the initialization parameter SKIP_UNUSABLE_INDEXES is set to true.
Some more Examples
CREATE INDEX expression_ndx
ON mytable ((mycola + mycolc) * mycolb);
SELECT mycolc FROM mytable
WHERE (mycola + mycolc) * mycolb <= 256;
..or a composite index..
CREATE INDEX example_ndx
ON myexample (mycola, UPPER(mycolb), mycolc);
SELECT mycolc FROM myexample
WHERE mycola = 55 AND UPPER(mycolb) = 'JONES';
Restriction & Rule Summary
The following restrictions apply to function based indexes. You may not index:
a) LOB columns
b) REF
c) Nested table column
d) Objects types with any of the above data types.
Function-based indexes must always follow these rules:
a) Cost Based optimizer only, must generate statistics after the index is created
b) Can not store NULL values (function can not return NULL under any circumstance)
c) If a user defined pl/sql routine is used for the function-based index, and is invalidated, the index will become "disabled"
d) Functions must be deterministic (always return the same value for a known input)
e) The index owner must have "execute" access on function used in the function-based index. Revocation of the privilege will render the index "disabled"
f) May have a B-Tree and Bitmap index type only
g) Can not use expressions that are based on aggregate functions, ie. SUM, AVG etc.
h) To alter a function-based index as enabled, the function used must be valid, deterministic and the signature of the function matches the signature of the function when it was created.
Joel P�rez

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

Why it is taking full table scan when index is available

Hi all,
I am facing a strange problem with index.
I created index on a column like
1. CREATE INDEX ASSETS_ARTIST_IDX2 ON ASSETS(artist).
SELECT asset.artist AS NAME FROM ASSETS asset WHERE asset.artist LIKE 'J%'
Explain Plan : INDEX RANGE SCAN
2. CREATE INDEX ASSETS_ARTIST_IDX2 ON ASSETS(UPPER (TRANSLATE (artist, ',;:"', ' ')));
SELECT asset.artist AS NAME FROM ASSETS asset WHERE UPPER (TRANSLATE (artist, ',;:"', ' ')) LIKE 'J%'
          Explain Plan : TABLE ACCESS FULL
first time it is taking index range scan,but in second situation scaning full table.Please let me know how to avoid the full table scan.
Regards,
Rajasekhar

Actually, I misseunderstood damorgan' s statement about NULL and OP did not provide table definition. So based on FTS I would say it is more likely column is NULLable, otherwise I would expect INDEX FAST SCAN:
SQL> create table emp1 as select * from emp
2 /
Table created.
SQL> create index emp1_idx1 on emp1(empno)
2 /
Index created.
SQL> exec dbms_stats.gather_table_stats('SCOTT','EMP1');
PL/SQL procedure successfully completed.
SQL> desc emp1
Name                                                                     Null?    Type
EMPNO                                                                             NUMBER(4)
ENAME                                                                             VARCHAR2(10)
JOB                                                                               VARCHAR2(9)
MGR                                                                               NUMBER(4)
HIREDATE                                                                          DATE
SAL                                                                               NUMBER(7,2)
COMM                                                                              NUMBER(7,2)
DEPTNO                                                                            NUMBER(2)
SQL> explain plan for
2 select empno
3 from emp1 where UPPER(TRANSLATE(empno, ',;:"', ' ')) LIKE '7%'
4 /
Explained.
SQL> @?\rdbms\admin\utlxpls
PLAN_TABLE_OUTPUT
Plan hash value: 2226897347
| Id | Operation         | Name | Rows | Bytes | Cost (%CPU)| Time     |
|   0 | SELECT STATEMENT |      |     1 |     4 |     3   (0)| 00:00:01 |
|* 1 | TABLE ACCESS FULL| EMP1 |     1 |     4 |     3   (0)| 00:00:01 |
Predicate Information (identified by operation id):
PLAN_TABLE_OUTPUT
   1 - filter(UPPER(TRANSLATE(TO_CHAR("EMPNO"),',;:"',' ')) LIKE '7%')
13 rows selected.
SQL> alter table emp1 modify empno not null
2 /
Table altered.
SQL> explain plan for
2 select empno
3 from emp1 where UPPER(TRANSLATE(empno, ',;:"', ' ')) LIKE '7%'
4 /
Explained.
SQL> @?\rdbms\admin\utlxpls
PLAN_TABLE_OUTPUT
Plan hash value: 2850860361
| Id | Operation        | Name      | Rows | Bytes | Cost (%CPU)| Time     |
|   0 | SELECT STATEMENT |           |     1 |     4 |     1   (0)| 00:00:01 |
|* 1 | INDEX FULL SCAN | EMP1_IDX1 |     1 |     4 |     1   (0)| 00:00:01 |
Predicate Information (identified by operation id):
PLAN_TABLE_OUTPUT
   1 - filter(UPPER(TRANSLATE(TO_CHAR("EMPNO"),',;:"',' ')) LIKE '7%')
13 rows selected.
SQL> SY.

Why full index scan is faster than full table scan?

Hi friends,
In the where clause of a query,if we give a column that contains index on it,then oracle uses index to search data rather than a TABLE ACCESS FULL Operation.
Why index searching is faster?

Sometimes it is faster to use index and sometimes it is faster to use full table scan. If your statistics are up to date Oracle is far more likely to get it right. If the query can be satisfied entirely from the index, then an index scan will almost always be faster as there are fewer blocks to read in the index than there would be if the table itself were scanned. However if the query must extract data from the table when that data is not in te index, then the index scan will be faster only if a small percentage of the rows are to be returned. Consiter the case of an index where 40% of the rows are returned. Assume the index values are distributed evenly among the data blocks. Assume 10 rows will fit in each data block thus 4 of the 10 rows will match the condition. Then the average datablock will be fetched 4 times since most of the time adjacent index entries will not be in the same block. The number of single datablock fetches will be about 4 times the number of datablocks. Compare this to a full table scan that does multiblock reads. Far fewer reads are required to read the entire table. Though it depends on the number of rows per block, a general rule is any query returning more than about 10% of a table is faster NOT using an index.

How to check small table scan full table scan if we will use index in where clause.

How to check small table scan full table scan if i will use index column in where clause.
Is there example link there i can test small table scan full table if index is used in where clause.

Use explain plan on your statement or set autotrace traceonly in your SQL*Plus session followed by the SQL you are testing.
For example
SQL> set autotrace traceonly
SQL> select *
2 from XXX
3 where id='fga';
no rows selected
Execution Plan
   0      SELECT STATEMENT Optimizer=ALL_ROWS (Cost=13 Card=1 Bytes=16
          5)
   1    0   PARTITION RANGE (ALL) (Cost=13 Card=1 Bytes=165)
   2    1     TABLE ACCESS (FULL) OF 'XXX' (TABLE) (Cost=13 Card
          =1 Bytes=165)
Statistics
          1 recursive calls
          0 db block gets
       1561 consistent gets
        540 physical reads
          0 redo size
       1864 bytes sent via SQL*Net to client
        333 bytes received via SQL*Net from client
          1 SQL*Net roundtrips to/from client
          0 sorts (memory)
          0 sorts (disk)
          0 rows processed

Selecting a column goes for a full table scan

Hi,
Oracle version 10.2
I have the below query:
SELECT   c.companyid,
         c.contactid,
         c.contactlname
    FROM contact c,company ic
   WHERE UPPER((c.contactlname)) LIKE CASE
           WHEN 'test' IS NULL THEN
            UPPER((c.contactlname))
           ELSE DECODE(1,
                   1,
                   '%' || 'TEST' || '%',
                   2,
                   'TEST' || '%',
                   3,
                   '%' || 'TEST',
                   4,
                   'TEST')
         END
     AND c.activeflag = DECODE('Y', 'N', 'Y', c.activeflag)
     AND ic.companyid=c.companyidthis is using the index on table company.
Explain plan:
SELECT STATEMENT, GOAL = ALL_ROWS               68     3523     176150
NESTED LOOPS               68     3523     176150
TABLE ACCESS FULL          CONTACT     65     3523     155012
INDEX UNIQUE SCAN          COMPANY_PK     0     1     6          Now if i include two more columns from the company table in the select statement the plan changes and it goes for a full table scan...
Query:
SELECT   ic.companyname,
         ic.companystatustypeid,
         c.companyid,
         c.contactid,
         c.contactlname
    FROM contact c,company ic
   WHERE UPPER((c.contactlname)) LIKE CASE
           WHEN 'test' IS NULL THEN
            UPPER((c.contactlname))
           ELSE DECODE(1,
                   1,
                   '%' || 'TEST' || '%',
                   2,
                   'TEST' || '%',
                   3,
                   '%' || 'TEST',
                   4,
                   'TEST')
         END
     AND c.activeflag = DECODE('Y', 'N', 'Y', c.activeflag)
     AND ic.companyid=c.companyidExplain Plan:
SELECT STATEMENT, GOAL = ALL_ROWS               2126     4121     403858
HASH JOIN               2126     4121     403858
TABLE ACCESS FULL          CONTACT     108     4121     185445
PARTITION LIST ALL               1959     1031340     54661020
   TABLE ACCESS FULL          COMPANY     1959     1031340     54661020     Any ideas why?

dont think so.
i tried removing the filters also:
Query:
SELECT -- ic.companyname,
       -- ic.companystatustypeid,
c.companyid,
         c.contactid,
         c.contactlname,
         c.contactfname,
         c.contactpositionid,
         c.contactroledesc,
         c.updateddate
    FROM contact c,company ic
   WHERE ic.companyid=c.companyidplan:
SELECT STATEMENT, GOAL = ALL_ROWS               109     73346     3520608
NESTED LOOPS               109     73346     3520608
TABLE ACCESS FULL          CONTACT     51     73346     3080532
INDEX UNIQUE SCAN          COMPANY_PK     0     1     6     Query:
SELECT   ic.companyname,
         ic.companystatustypeid,
c.companyid,
         c.contactid,
         c.contactlname,
         c.contactfname,
         c.contactpositionid,
         c.contactroledesc,
         c.updateddate
    FROM contact c,company ic
   WHERE ic.companyid=c.companyid
     Plan:
SELECT STATEMENT, GOAL = ALL_ROWS               2462     73346     6894524
HASH JOIN               2462     73346     6894524
TABLE ACCESS FULL          CONTACT     51     73346     3080532
PARTITION LIST ALL               1348     973674     50631048
   TABLE ACCESS FULL          COMPANY     1348     973674     50631048     Does the columns selected have an impact on the plan?? I thought the plan is derived on basis of the join conditions...

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?

Order by column has index which results in full table scan

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