General queries regarding explain plan and query

Hello Oracle buddies,
I have few badly formed queries with plenty of nested loops, merge join cartesian , plenty of sorting and in the query so many sub queries and all.. The cost of the queries are high like anything.
some even has 130Crore of cost .
When I got the chance to look into those quries I test them in Non Prod systems and which almost have 90-95% similar data as it was refresh by PROD few weeks back.
I found few queries are having the same explain plan but cost is less like anything. for example 5000 or 6000.
When I check for the possibilities of wrong statistics I found they just collect with default setting...
In Non prod I saw only the auto stat job is ran and most of the tables are having the stats which are of last analyzed on the day of refresh.
Now what could be so differentiating factor that drives a queries' cost lesser than Prod systems, when the data is almost same. Also if prod ssystem is gather by only gather_schema_stat('SCHEMA_NAME') then it should carry the same stat in non prod while refreshing. I know ppl do not gather stat on test only auto job is running ...
I need to have clear prove before I can have a clear understanding..
Please help me to know what factors could be differentiating?
-Regards,
J_DBA_Sourav

j_DBA_sourav wrote:
Hello Jonathan,
Thanks for the reply. The team refreshed it, by expdp/impdp method where by default statistics are included. In that case?
Is this problem probable to happen due to statistics only or anything else is also responsible. Even the explain plan is same.
Please through some light on it.
Auto job is on as I stated earlier but in test systems most of the tables are showing refreshed date as last_analyzed
-Regards
JDS
Anything that puts the stats out of sync with each other may be sufficient to cause problems. Any queries that depend on sysdate may cause a problem.
As a simple check: select table_name, last_analyzed from user_tables on the two systems, with some order by clause (e.g. table_name), and see how many tables were analysed at different times - anything on either system after the exp/imp could be part of your problem.
Regards
Jonathan Lewis
http://jonathanlewis.wordpress.com
Now on Twitter: @jloracle

Similar Messages

Query Regarding Explain Plan on Query

Hello,
I have one big query which shows report of 50000 daily records from @ 20,00,000 records.
I have two databases UAT and PROD.when i do Explain Plan on the query is these different database i get the different plan where everything is same in both database.
In UAT it is doing Index scan where as in PROD it is doing Full TableScan. Below are the results.
In production it is not using any of the indexes present but in UAT it is.What could be the reasong behind this?

Sure.
UAT Explain Plan (Please copy in Textpad for better View)
SELECT STATEMENT, GOAL = HINT: ALL_ROWS     Cost=371     Cardinality=238     Optimizer=HINT: ALL_ROWS     Bytes=134470
VIEW     Object owner=SWNET1          Cost=371     Cardinality=238          Bytes=134470
COUNT STOPKEY
VIEW     Object owner=SWNET1          Cost=371     Cardinality=238          Bytes=131376
SORT ORDER BY STOPKEY          Cost=371     Cardinality=238          Bytes=54026
FILTER
HASH JOIN RIGHT ANTI          Cost=370     Cardinality=238          Bytes=54026
INLIST ITERATOR
TABLE ACCESS BY INDEX ROWID     Object owner=SWNET1     Object name=IS_TB_END_POINT     Cost=1     Cardinality=1     Optimizer=ANALYZED     Bytes=31
INDEX RANGE SCAN          Object owner=SWNET1     Object name=IS_UK_EP_NAME     Cost=1     Cardinality=1     Optimizer=ANALYZED
TABLE ACCESS BY INDEX ROWID     Object owner=SWNET1     Object name=IS_TB_TRANSACTION     Cost=368     Cardinality=253     Optimizer=ANALYZED     Bytes=49588
INDEX FULL SCAN          Object owner=SWNET1     Object name=IS_IX_T_DESTINATION_EP     Cost=18     Cardinality=13909     Optimizer=ANALYZED
PRODUCTION Explain Plan
SELECT STATEMENT, GOAL = HINT: ALL_ROWS               Cost=65702     Cardinality=1000     Optimizer=HINT: ALL_ROWS     Bytes=565000
VIEW     Object owner=SWNET1          Cost=65702     Cardinality=1000          Bytes=565000
COUNT STOPKEY
VIEW     Object owner=SWNET1          Cost=65702     Cardinality=38739          Bytes=21383928
SORT ORDER BY STOPKEY          Cost=65702     Cardinality=38739          Bytes=9646011
FILTER
HASH JOIN RIGHT ANTI          Cost=63616     Cardinality=38739          Bytes=9646011
INLIST ITERATOR
TABLE ACCESS BY INDEX ROWID     Object owner=SWNET1     Object name=IS_TB_END_POINT     Cost=1     Cardinality=2     Optimizer=ANALYZED     Bytes=64
INDEX UNIQUE SCAN          Object owner=SWNET1     Object name=IS_UK_EP_NAME     Cost=1     Cardinality=2     Optimizer=ANALYZED
TABLE ACCESS FULL          Object owner=SWNET1     Object name=IS_TB_TRANSACTION     Cost=63614     Cardinality=44697     Optimizer=ANALYZED     Bytes=9699249
Index Query (Same on both places)
create index IS_IX_T_DESTINATION_EP on IS_TB_TRANSACTION (T_DESTINATION_EP)
tablespace IS_XML_IND
pctfree 10
initrans 2
maxtrans 255
storage
initial 128M
next 128K
minextents 1
maxextents unlimited
pctincrease 0
);

Explain Plan and COST

Hi,
Is there any relationship between the cost factor in the explain plan and query execution time. I have come across situations in both ways, i.e. high cost and low execution time, low cost and high execution time. What parameters do we need to consider in tuning a query high cost or low cost?So my assumption is that the lower cost does not guarantee faster response time. Again i have have seen many people try to reduce the cost first.Can anyone help me on this issue please.
Thanks-Bhaskar

Cost is a metric that Oracle uses to estimate the runtime of a query. However, it is not something that you probably ought to pay a lot of attention to. If you are looking at the performance of a query, you are presumably operating on the assumption that the optimizer may have chosen an incorrect plan. If the optimizer chose an incorrect plan then by definition the cost is incorrect. If the cost is correct then, by definition, Oracle chose the correct plan.
It makes much more sense to focus on things like the cardinality of each step (the number of rows each step in the plan is expected to return). If the cardinality estimates are correct (or reasonably close), then the optimizer probably chose the correct plan. If the cardinality estimates are way off, the optimizer probably chose a less than optimal plan. And when you find the first step where the cardinality estimates are wildly incorrect, you'll know where you need to start focusing your tuning efforts.
Justin

Query regarding Explain Plan

Hi,
I have a query regarding explain plan. While we gather the statistics then optimize choose the best possible plan out of the explain plans available. If we do not gather statistics on a table for a long time then which plan it choose:
If it will continue to use the same plan as it use in the starting when statistics were gathered or will change the plan as soon as dml activities performed and statistics getting old.
Thanks
GK

Hi,
Aman.... wrote:
Gulshan wrote:
Hi,
I have a query regarding explain plan. While we gather the statistics then optimize choose the best possible plan out of the explain plans available. If we do not gather statistics on a table for a long time then which plan it choose:The same plan which it has chosen in the starting with the previous statistics. The plan won't change automatically as long as you won't refresh the statistics. This is wrong even for Oracle 9i. Here are couple of examples when a plan might change with the same optimizer statistics:
* when you have a histogram on a column and are not a bright person to use bind variables, you might get a completely different execution plan because of a different incoming value. All that is needed to fall into this habit - a soft parse, which might be due to different reasons, for instance, due to session parameter modification (which also might change a plan even without a histogram)
* Starting with 10g, CBO makes adjustments to cardinality estimates for out of range values appeared in predicates

How to proceed further once the explain plan and trace files are generated?

Hi Friends,
I need to improve the performance of on of the views that i am working on.
As suggested in the thread - http://forums.oracle.com/forums/thread.jspa?threadID=863295&tstart=0 , i gave generated the explain plan and the trace file.
From the explain plan, we can see the expensive operations for the query.
Can any one please tell, how to proceed further from here on i.e. how to make this expensive operations less expensive?
For ex: FULL TABLE SCAN might be an expensive operation when the table has indexes.In such cases, how can we avoid such operations to make query faster?
Regards,
Sreekanth Munagala.

Hi Veena,
An earlier post by you regarding P45 is as below
Starter report P45(3) / P46 efiling for UK
from my understanding though i have not worked on GB Payroll you have said that you deleted IT 65 details of leaver,however there must be clusters generated in system from where the earlier data needs to be deleted and may be that is why you are facing the issue.
In Indian payroll when we execute text file for efiling of tax after challan mapping all the data compiles and sits in PCL cluster and therefore we are unable to generate form 16 with proper output,here we delete the clusters and rerun again the mappings and then check form 16.
Hope this might help you,Experts have suggested you earlier also,they may correct me for this.
Salil

Efficient way to read through big explain plan and genterate html explain plan for sql id's executed in past

Hi,
I have a sql which is recently having a performance problems in Production. I have generated a explain plan for it trying to find out what it is doing but plan itself is close to 1000 lines. I want to check if there is any efficient way to go through big plan like this one and quickly find the damaging areas..
2) I also wanted to know if there is way to generate explain plans in HTML format which executed in past and have entry in dba_hist_sqltext.
3) I also have two sql_monitor reports which I want to compare. is there any efficient way to do it as well?
Please share your thoughts!
Thanks in advance!
Regards,
Suman-

Hi,
I suggest you can try running sql advisor on the query maybe something fruitful comes up
http://www.oracle-base.com/articles/11g/sql-access-advisor-11gr1.php
I am not sure about the explain plan being printed in html format but
You may also want to try the sqlhistory.sql query from below page
http://evdbt.com/scripts/
I have used it many times to check on executions and explain plans which may have changed over the period
I have faced it many times , the query picks up a bad explain plan and performs poorly

Queries regarding Flash Builder and Augmented Reality.

I am Sarat from India. I'm a software engineer with working knowledge of Java, so Flash AS and OOP are understandable for me. I am working on an augmented reality project. I am quite new to Flash, Adobe Community and I've got some queries regarding Augmented Reality and Flash Builder:
1. Flash Builder 4.6 comes with a default Flex 4.6 SDK. However, Flex 4.6 SDK wasn't allowing me to compile and run some example files. So I've downloaded Flex 4.0A version from Adobe.com. Now the examples are running fine, but would there be any problem if i try deploying such projects in a website or as a desktop app? Once the code is compiled into a swf file, the flex framework used doesn't make much difference, does it?
2. Would the AR project run effectively on a website, given various internet/processor speeds worldwide? Would the effectiveness of the AR project, deployed on a website, depend on the number of triangles in the 3D models i.e. dae files? Because as per my understanding heavy models implies more time to download the flash app into the local browser from the internet and more time to render them by the papervision 3D engine right?
3. Can we develop a stand alone desktop AR app using Flash Builder? Using Adobe AIR we can, i guess. Please refer some tutorial, if possible.
4. I've seen that we can implement multiple-marker-tracking AR using vectors/arrays in AS. Would there be any performance issues depending on the size of the vectors/arrays used.
5. Can someone please mention some tips to improve performance of an AR app (desktop app and web app)?
6. What would be, approximately, the cost of FLARManager, FLARToolkit commercial versions, if you have any idea? I've gone through their website but they did not mention the costs.
7. Would applying bitmap material to the dae models pull down the web app/mobile app/desktop app performance, given some 4 to 5 dae models in the scene?
8. Is it advisable to use multiple markers with multiple dae models or single marker with Flash-based GUI option to load different models onto the same marker?
It would be very helpful for me if someone could answer my above queries.
Sarat.

#1, If it compiles then you have no issue. There's no reason at this point not to use 4.6. You should bundle a captive runtime to assure the users computer won't need to have AIR installed at all.
#2, Papervision is old. Use the Stage3D and/or a wrapper framework. As far as the generic "If I download lots of data will it take the user more time to load it", well, of course. Just don't make the loading experience painful. Entertain them while they way or find ways of displaying data sooner than later. If it's desirable on the web has more to do with the context of the app and the device displaying it. In other words, a phone user would find it easy but obviously not a desktop user.
#3, Definitely referring you to Google on that one.
#4, Size always matters, it's common sense. The more you process the harder it is. While I haven't done AR I've used the Microsoft Kinect SDK and ANE and tracking was extremely fast but limited. From what I've seen and your basic built in location and direction hardware on any mobile device you shouldn't have much trouble. Depends on what you're doing.
#5, This discussion would be way too large for a forum. You'd need to consult a firm experienced in AR development.
#6, "Applications using the commercial license do not have to provide source code, but must pay a licensing fee. Contact ARToolworks at [email protected] for more information." They will base your price on your product, there is no single price.
#7, The models could be huge and elaborate or tiny and simple which changes the answer. Consult the answer in #4. Ultimately most people are getting on fast networks with mobile and excessively fast on desktop/wifi. Size matters a lot less than 3 years ago.
#8, Depends on what you're doing. You have to explain it.

Explain plan for query with variables

Trying to Explain plan for some sql in sql*plus. The query has a variable in it. How do I do this ?
I did look into explain plan and dbms_xplan but could not find anything with variables

use sqlplus bind variables:
SQL> --define variable
SQL> var x varchar2
SQL> -- notice the colon prefixing the variable
SQL> explain plan for select * from customer where cid = :x;
Explained.
SQL> select * from table( dbms_xplan.display );
PLAN_TABLE_OUTPUT
Plan hash value: 1709312366
| Id | Operation                   | Name     | Rows | Bytes | Cost (%CPU)| Time     |
|   0 | SELECT STATEMENT            |          |     1 |    67 |     2   (0)| 00:00:01 |
|   1 | TABLE ACCESS BY INDEX ROWID| CUSTOMER |     1 |    67 |     2   (0)| 00:00:01 |
|* 2 |   INDEX RANGE SCAN          | CID      |     1 |       |     1   (0)| 00:00:01 |
Predicate Information (identified by operation id):
   2 - access("CID"=:X)
14 rows selected.the variable does not need to be set to explain the query, since explain does not actually execute.
Edited by: shoblock on Nov 6, 2008 4:51 PM

Problems with explain plan and statement

Hi community,
I have migrated a j2ee application from DB2 to Oracle.
First some facts of our application and database instance:
We are using oracle version 10.2.0.3 and driver version 10.2.0.3. It runs with charset Unicode 3.0 UTF-8.
Our application is using Tomcat as web container and jboss as application server. We are only using prepared statements. So if I talk about statements I always mean prepared statements. Also our application is setting the defaultNChar property to true because every char and varchar field has been created as an nchar and nvarchar.
We have some jsp sites that contains lists with search forms. Everytime I enter a value to the form that returns a filled resultset, the lists are performing great. But everytime I enter a value that returns an empty resultset, the lists are 100 times slower. The jsp sites are running in the tomcat environment and submitting their statements directly to the database. The connections are pooled by dbcp. So what can cause this behaviour??
To anaylze this problem I started logging all statements and filled-in search field values and combinations that are executed by the lists described above. I also developed a standalone helper tool that reads the logged statements, executes them to the database and generates an explain plan for every statement. But now there appears a strange situation. Every statement, that performs really fast within our application, is now executed by the helper tool extremely slow. So I edited some jsp pages within our application to force an explain plan from there (tomcat env). So when I'm executing the same statement I'm getting with the exactly same code two completely different explain plans.
First the statement itself:
select LINVIN.BBASE , INVINNUM , INVINNUMALT , LINVIN.LSUPPLIERNUM , LSUPPLIERNUMEXT , LINVIN.COMPANYCODE , ACCOUNT , INVINTXT , INVINSTS , INVINTYP , INVINDAT , RECEIPTDAT , POSTED , POSTINGDATE , CHECKCOSTCENTER , WORKFLOWIDEXT , INVINREFERENCE , RESPONSIBLEPERS , INVINSUM_V , INVINSUMGROSS_V , VOUCHERNUM , HASPOSITIONS , PROCESSINSTANCEID , FCURISO_V , LSUPPLIER.AADDRLINE1 from LINVIN, LSUPPLIER where LINVIN.BBASE = LSUPPLIER.BBASE and LINVIN.LSUPPLIERNUM = LSUPPLIER.LSUPPLIERNUM and LINVIN.BBASE = ? order by LINVIN.BBASE, INVINDAT DESC
Now the explain plan from our application:
| Id | Operation | Name | Rows | Bytes | Cost (%CPU)| Time |
| 0 | SELECT STATEMENT | | 101 | 28583 | 55 (0)| 00:00:01 |
| 1 | NESTED LOOPS | | 101 | 28583 | 55 (0)| 00:00:01 |
| 2 | TABLE ACCESS BY INDEX ROWID| LINVIN | 93709 | 12M| 25 (0)| 00:00:01 |
|* 3 | INDEX RANGE SCAN | LINV_INVDAT | 101 | | 1 (0)| 00:00:01 |
| 4 | TABLE ACCESS BY INDEX ROWID| LSUPPLIER | 1 | 148 | 1 (0)| 00:00:01 |
|* 5 | INDEX UNIQUE SCAN | PK_177597 | 1 | | 1 (0)| 00:00:01 |
Predicate Information (identified by operation id):
3 - access("LINVIN"."BBASE"=:1)
filter("LINVIN"."BBASE"=:1)
5 - access("LSUPPLIER"."BBASE"=:1 AND "LINVIN"."LSUPPLIERNUM"="LSUPPLIER"."LSUPPLIERNUM")
Now the one from the standalone tool:
| Id | Operation | Name | Rows | Bytes |TempSpc| Cost (%CPU)| Time |
| 0 | SELECT STATEMENT | | 93773 | 25M| | 12898 (1)| 00:02:35 |
| 1 | SORT ORDER BY | | 93773 | 25M| 61M| 12898 (1)| 00:02:35 |
|* 2 | HASH JOIN | | 93773 | 25M| 2592K| 7185 (1)| 00:01:27 |
| 3 | TABLE ACCESS BY INDEX ROWID| LSUPPLIER | 16540 | 2390K| | 332 (0)| 00:00:04 |
|* 4 | INDEX RANGE SCAN | LSUPPLIER_HAS_BASE_FK | 16540 | | | 11 (0)| 00:00:01 |
| 5 | TABLE ACCESS BY INDEX ROWID| LINVIN | 93709 | 12M| | 6073 (1)| 00:01:13 |
|* 6 | INDEX RANGE SCAN | LINVOICE_BMDT_FK | 93709 | | | 84 (2)| 00:00:02 |
Predicate Information (identified by operation id):
2 - access("LINVIN"."BBASE"="LSUPPLIER"."BBASE" AND "LINVIN"."LSUPPLIERNUM"="LSUPPLIER"."LSUPPLIERNUM")
4 - access("LSUPPLIER"."BBASE"=:1)
6 - access("LINVIN"."BBASE"=:1)
The size of the tables are: LINVIN - 383.692 Rows, LSUPPLIER - 115.782 Rows
As you can see the one executed from our application is much faster than the one from the helper tool. So why picks oracle a completely different explain plan for the same statement? An why is a hash join much slower than a nested loop? Because If I'm right a nested loop should only be used when the tables are pretty small..
I also tried to play with some parameters:
I set optimizer_index_caching to 100 and optimizer_index_cost_adj to 30. I also changed optimizer_mode to FIRST_ROWS_100.
I would really appreciated, if somebody can help me with this issue, because I'm really getting more and more distressed...
Thanks in advance,
Tobias
Edited by: tobiwan on Sep 3, 2008 11:49 PM
Edited by: tobiwan on Sep 3, 2008 11:50 PM
Edited by: tobiwan on Sep 4, 2008 12:01 AM
Edited by: tobiwan on Sep 4, 2008 12:02 AM
Edited by: tobiwan on Sep 4, 2008 12:04 AM
Edited by: tobiwan on Sep 4, 2008 12:06 AM
Edited by: tobiwan on Sep 4, 2008 12:06 AM
Edited by: tobiwan on Sep 4, 2008 12:07 AM

tobiwan wrote:
Hi again,
Here ist the answer:
The problem, because I got two different explain plans, was that the external tool uses the NLS sesssion parameters coming from the OS which are in my case "de/DE".
Within our application these parameters are changed to "en/US"!! So if I'm calling in my external tool the java function Locale.setDefault(new Locale("en","US")) before connecting to the database the explain plans are finally equal.That might explain why you got two different execution plan, because one plan was obviously able to avoid a SORT ORDER BY operation, whereas the second plan required to run SORT ORDER BY operation, obviously because of the different NLS_SORT settings. An index by default uses the NLS_SORT = 'binary' order whereas ORDER BY obeys the NLS_SORT setting, which probably was set to 'GERMAN' in your "external tool" case. You can check the "NLS_SESSION_PARAMETERS" view to check your current NLS_SORT setting.
For more information regarding this issue, see my blog note I've written about this some time ago:
http://oracle-randolf.blogspot.com/2008/09/getting-first-rows-of-large-sorted.html
Now let me make a guess why you observe the behaviour that it takes so long if your result set is empty:
The plan avoiding the SORT ORDER BY is able to return the first rows of the result set very quickly, but could take quite a while until all rows are processed, since it requires potentially a lot of iterations of the loop until everything has been processed. Your front end probably by default only display the first n rows of the result set and therefore works fine with this execution plan.
Now if the result set is empty, depending on your data, indexes and search criteria, Oracle has to work through all the data using the inefficient NESTED LOOP approach only to find out that no data has been found, and since your application attempts to fetch the first n records, but no records will be found, it has to wait until all data has been processed.
You can try to reproduce this by deliberately fetching all records of a query that returns data and that uses the NESTED LOOP approach... It probably takes as long as in the case when no records are found.
Note that you seem to use bind variables and 10g, therefore you might be interested that due to the "bind variable peeking" functionality you might potentially end up with "unstable" plans depending on the values "peeked" when the statement is parsed.
For more information, see this comprehensive description of the issue:
http://www.pythian.com/blogs/867/stabilize-oracle-10gs-bind-peeking-behaviour-by-cutting-histograms
Note that this changes in 11g with the introduction of the "Adaptive Cursor Sharing".
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/

Strange explain plan when query SYS tables

Oracle Version 9.2.0.7
We have an application that runs the following query on Oracle 9.2.0.7
SELECT T1.TABLE_NAME,T1.COLUMN_NAME, T1.SRID, T2.SDO_UB, T2.SDO_LB, T1.OWNER FROM ALL_SDO_GEOM_METADATA T1, TABLE(T1.DIMINFO) T2 WHERE T1.OWNER=UPPER(:"SYS_B_0") AND T1.TABLE_NAME=UPPER(:"SYS_B_1")
Without the self join the query is fine, but with the self join on our customers database the explain plan is doing full table scans and Hash Joins on SYS tables and takes 2 minutes.
Rows Row Source Operation
2 FILTER
2 NESTED LOOPS
1 TABLE ACCESS FULL SDO_GEOM_METADATA_TABLE
2 COLLECTION ITERATOR PICKLER FETCH
1 UNION-ALL
0 FILTER
0 NESTED LOOPS OUTER
0 HASH JOIN
37 TABLE ACCESS FULL TS$
0 HASH JOIN OUTER
0 NESTED LOOPS OUTER
0 NESTED LOOPS OUTER
0 NESTED LOOPS
1 NESTED LOOPS
1 TABLE ACCESS BY INDEX ROWID USER$
1 INDEX UNIQUE SCAN I_USER1 (object id 44)
1 TABLE ACCESS BY INDEX ROWID OBJ$
1 INDEX RANGE SCAN I_OBJ2 (object id 37)
0 TABLE ACCESS CLUSTER TAB$
1 INDEX UNIQUE SCAN I_OBJ# (object id 3)
0 TABLE ACCESS CLUSTER SEG$
0 INDEX UNIQUE SCAN I_FILE#_BLOCK# (object id 9)
0 TABLE ACCESS BY INDEX ROWID OBJ$
0 INDEX UNIQUE SCAN I_OBJ1 (object id 36)
0 TABLE ACCESS FULL USER$
0 INDEX UNIQUE SCAN I_OBJ1 (object id 36)
0 NESTED LOOPS
0 FIXED TABLE FULL X$KZSRO
0 INDEX RANGE SCAN I_OBJAUTH2 (object id 109)
0 FIXED TABLE FULL X$KZSPR
0 FILTER
0 NESTED LOOPS OUTER
0 HASH JOIN
54 TABLE ACCESS FULL USER$
0 HASH JOIN
29447 TABLE ACCESS FULL OBJ$
0 HASH JOIN OUTER
0 HASH JOIN OUTER
0 HASH JOIN OUTER
0 NESTED LOOPS
0 NESTED LOOPS OUTER
0 NESTED LOOPS OUTER
0 NESTED LOOPS
0 NESTED LOOPS
0 NESTED LOOPS
1 NESTED LOOPS
1 TABLE ACCESS BY INDEX ROWID USER$
1 INDEX UNIQUE SCAN I_USER1 (object id 44)
1 TABLE ACCESS BY INDEX ROWID OBJ$
1 INDEX RANGE SCAN I_OBJ2 (object id 37)
0 TABLE ACCESS CLUSTER TAB$
1 INDEX UNIQUE SCAN I_OBJ# (object id 3)
0 TABLE ACCESS CLUSTER TS$
0 INDEX UNIQUE SCAN I_TS# (object id 7)
0 TABLE ACCESS CLUSTER COL$
0 TABLE ACCESS CLUSTER SEG$
0 INDEX UNIQUE SCAN I_FILE#_BLOCK# (object id 9)
0 TABLE ACCESS BY INDEX ROWID OBJ$
0 INDEX UNIQUE SCAN I_OBJ1 (object id 36)
0 TABLE ACCESS CLUSTER COLTYPE$
0 TABLE ACCESS FULL USER$
0 TABLE ACCESS FULL OBJ$
0 TABLE ACCESS FULL USER$
0 INDEX UNIQUE SCAN I_OBJ1 (object id 36)
0 NESTED LOOPS
0 FIXED TABLE FULL X$KZSRO
0 INDEX RANGE SCAN I_OBJAUTH2 (object id 109)
0 FIXED TABLE FULL X$KZSPR
1 FILTER
1 NESTED LOOPS
1 NESTED LOOPS OUTER
1 NESTED LOOPS
1 TABLE ACCESS BY INDEX ROWID USER$
1 INDEX UNIQUE SCAN I_USER1 (object id 44)
1 TABLE ACCESS BY INDEX ROWID OBJ$
1 INDEX RANGE SCAN I_OBJ2 (object id 37)
0 INDEX UNIQUE SCAN I_TYPED_VIEW1 (object id 105)
1 INDEX UNIQUE SCAN I_VIEW1 (object id 104)
0 NESTED LOOPS
0 FIXED TABLE FULL X$KZSRO
0 INDEX RANGE SCAN I_OBJAUTH2 (object id 109)
0 FIXED TABLE FULL X$KZSPR
On our development database it takes 0.07 sec with no full table scans and no hash joins.
Rows Row Source Operation
2 NESTED LOOPS
1 TABLE ACCESS BY INDEX ROWID SDO_GEOM_METADATA_TABLE
1 INDEX RANGE SCAN SDO_GEOM_IDX (object id 36753)
1 UNION-ALL
0 FILTER
0 NESTED LOOPS
0 NESTED LOOPS OUTER
0 NESTED LOOPS OUTER
0 NESTED LOOPS OUTER
0 NESTED LOOPS OUTER
0 NESTED LOOPS
1 NESTED LOOPS
1 TABLE ACCESS BY INDEX ROWID USER$
1 INDEX UNIQUE SCAN I_USER1 (object id 44)
1 TABLE ACCESS BY INDEX ROWID OBJ$
1 INDEX RANGE SCAN I_OBJ2 (object id 37)
0 TABLE ACCESS CLUSTER TAB$
1 INDEX UNIQUE SCAN I_OBJ# (object id 3)
0 TABLE ACCESS BY INDEX ROWID OBJ$
0 INDEX UNIQUE SCAN I_OBJ1 (object id 36)
0 INDEX UNIQUE SCAN I_OBJ1 (object id 36)
0 TABLE ACCESS CLUSTER USER$
0 INDEX UNIQUE SCAN I_USER# (object id 11)
0 TABLE ACCESS CLUSTER SEG$
0 INDEX UNIQUE SCAN I_FILE#_BLOCK# (object id 9)
0 TABLE ACCESS CLUSTER TS$
0 INDEX UNIQUE SCAN I_TS# (object id 7)
0 NESTED LOOPS
0 FIXED TABLE FULL X$KZSRO
0 INDEX RANGE SCAN I_OBJAUTH2 (object id 109)
0 FIXED TABLE FULL X$KZSPR
0 FILTER
0 NESTED LOOPS
0 NESTED LOOPS
0 NESTED LOOPS OUTER
0 NESTED LOOPS OUTER
0 NESTED LOOPS OUTER
0 NESTED LOOPS OUTER
0 NESTED LOOPS OUTER
0 NESTED LOOPS OUTER
0 NESTED LOOPS
0 NESTED LOOPS
0 NESTED LOOPS
0 NESTED LOOPS
1 NESTED LOOPS
1 TABLE ACCESS BY INDEX ROWID USER$
1 INDEX UNIQUE SCAN I_USER1 (object id 44)
1 TABLE ACCESS BY INDEX ROWID OBJ$
1 INDEX RANGE SCAN I_OBJ2 (object id 37)
0 TABLE ACCESS CLUSTER TAB$
1 INDEX UNIQUE SCAN I_OBJ# (object id 3)
0 TABLE ACCESS CLUSTER TS$
0 INDEX UNIQUE SCAN I_TS# (object id 7)
0 TABLE ACCESS CLUSTER COL$
0 TABLE ACCESS CLUSTER COLTYPE$
0 TABLE ACCESS CLUSTER SEG$
0 INDEX UNIQUE SCAN I_FILE#_BLOCK# (object id 9)
0 TABLE ACCESS BY INDEX ROWID OBJ$
0 INDEX UNIQUE SCAN I_OBJ1 (object id 36)
0 TABLE ACCESS CLUSTER USER$
0 INDEX UNIQUE SCAN I_USER# (object id 11)
0 TABLE ACCESS BY INDEX ROWID OBJ$
0 INDEX UNIQUE SCAN I_OBJ1 (object id 36)
0 TABLE ACCESS CLUSTER USER$
0 INDEX UNIQUE SCAN I_USER# (object id 11)
0 INDEX UNIQUE SCAN I_OBJ1 (object id 36)
0 TABLE ACCESS BY INDEX ROWID OBJ$
0 INDEX RANGE SCAN I_OBJ3 (object id 38)
0 TABLE ACCESS CLUSTER USER$
0 INDEX UNIQUE SCAN I_USER# (object id 11)
0 NESTED LOOPS
0 FIXED TABLE FULL X$KZSRO
0 INDEX RANGE SCAN I_OBJAUTH2 (object id 109)
0 FIXED TABLE FULL X$KZSPR
1 FILTER
1 NESTED LOOPS
1 NESTED LOOPS OUTER
1 NESTED LOOPS
1 TABLE ACCESS BY INDEX ROWID USER$
1 INDEX UNIQUE SCAN I_USER1 (object id 44)
1 TABLE ACCESS BY INDEX ROWID OBJ$
1 INDEX RANGE SCAN I_OBJ2 (object id 37)
0 INDEX UNIQUE SCAN I_TYPED_VIEW1 (object id 105)
1 INDEX UNIQUE SCAN I_VIEW1 (object id 104)
0 NESTED LOOPS
0 FIXED TABLE FULL X$KZSRO
0 INDEX RANGE SCAN I_OBJAUTH2 (object id 109)
0 FIXED TABLE FULL X$KZSPR
2 COLLECTION ITERATOR PICKLER FETCH
ALL_SDO_GEOM_METADATA is a view in the MDSYS schema (generated by Oracle ).
SELECT SDO_OWNER OWNER,
SDO_TABLE_NAME TABLE_NAME,
SDO_COLUMN_NAME COLUMN_NAME,
SDO_DIMINFO DIMINFO,
SDO_SRID SRID
FROM SDO_GEOM_METADATA_TABLE
WHERE
(exists
(select table_name from all_tables
where table_name=sdo_table_name
and owner = sdo_owner
union all
select table_name from all_object_tables
where table_name=sdo_table_name
and owner = sdo_owner
union all
select view_name table_name from all_views
where view_name=sdo_table_name
and owner = sdo_owner))
Statistics have been gathered for the MDSYS user.
If this had not been SYS schema I would have immediately concluded that fresh statistics are required. The SYS objects concerend are valid with all indexes
From my understanding you are not meant to gather stats for the SYS schema in Oracle 9 as Data Dictionary queries still uses RBO?
Any ideas as to why Oracle is doing full table scans when querying SYS tables? The optimizer_mode is set to FIRST_ROWS.
Any ideas greatly recevied.
Thanks

Maybe I'm missing something but this:
INDEX FULL SCAN SISESTAT I0_ESTRUTURA_COMERCIALindicates that one of those indexes is being used.
This:
T_ESTRUTURA_COMERCIALIs nowhere to be found in your Explain Plan. It appears that either you have posted the wrong plan
or Oracle is doing a query rewrite to a materialized view.

Explain Plan and Execution Plan in 10gR2.

Hi,
Version 10.2.0.1.0.
I have two questions:
1) If the explain plan differs from the execution path in this version, then, is it safe to assume that the statistics are stale (or not gathered at all) on the underlying tables?
2) Can you in any way make a query use RBO instead of CBO? (I know it doesn't make any sense since CBO is lot smarter, but, for purely academic reasons).
Thank you,
Rahul.

The rule based optimizer is most definitely present in 10gR2. It might not be in the documentation, but it is still there.
C:\sql>sqlplus test/test
SQL*Plus: Release 10.2.0.2.0 - Production on Tue Oct 10 15:43:34 2006
Copyright (c) 1982, 2005, Oracle. All Rights Reserved.
Connected to:
Oracle Database 10g Enterprise Edition Release 10.2.0.2.0 - Production
With the Partitioning, OLAP and Data Mining options
test@SVTEST> set autotrace traceonly
test@SVTEST> alter session set optimizer_mode=rule;
Session altered.
Elapsed: 00:00:00.01
test@SVTEST> select * from dual;
Elapsed: 00:00:00.03
Execution Plan
Plan hash value: 272002086
| Id | Operation | Name |
| 0 | SELECT STATEMENT | |
| 1 | TABLE ACCESS FULL| DUAL |
Note
- rule based optimizer used (consider using cbo)
Statistics
1 recursive calls
0 db block gets
3 consistent gets
2 physical reads
0 redo size
407 bytes sent via SQL*Net to client
381 bytes received via SQL*Net from client
2 SQL*Net roundtrips to/from client
0 sorts (memory)
0 sorts (disk)
1 rows processed
test@SVTEST>

Explain plan and SQL profile.

Hi ,
I got a sql tuning result for one query , and i need to understand the below fileds in the explain plan
operation lineid object object_type order rows bytes cost time cpucost iocost
any document to understand will be appreciated
and in recomendation i got Consider accepting the recommended SQL profile. suppose if it was not feasible after accepting the SQL profile can i revert back.
Thanks

user12266475 wrote:
Hi ,
I got a sql tuning result for one query , and i need to understand the below fileds in the explain plan
operation lineid object object_type order rows bytes cost time cpucost iocost
any document to understand will be appreciated
and in recomendation i got Consider accepting the recommended SQL profile. suppose if it was not feasible after accepting the SQL profile can i revert back.
Thankshttp://docs.oracle.com/cd/E11882_01/server.112/e16638/toc.htm
Thread: HOW TO: Post a SQL statement tuning request - template posting
HOW TO: Post a SQL statement tuning request - template posting

Explain plan for Query performance

Hi Gurus,
I need to improve the performance of a procedure. The procedure has the below QUery. I dont have Idea on how to imrpove the perf by seeing the explain plan. Can anyone please help me to explain where I need to change the code.
The below are the code and Explain plan for the same.
-----------Code----------------------------
SELECT IV_STORECODE AS STORECODE,
                               TO_CHAR(RD.ITEMCODE) AS ITEMCODE,
                               C.ITEMCATEGORYNAME,
                               ISUB.ITEMSUBCATEGORY1NAME
                          FROM RECEIPTS R
                         INNER JOIN RECEIPTDETAILS RD
                            ON R.RECEIPTID = RD.RECEIPTID
                         INNER JOIN ITEMCOMPANY IC
                            ON IC.ITEMCODE = RD.ITEMCODE
                         INNER JOIN ITEMCATEGORY C
                            ON IC.ITEMCATEGORY = C.ITEMCATEGORYID
                         LEFT OUTER JOIN ITEMSUBCATEGORY1 ISUB
                            ON ISUB.ITEMSUBCATEGORY1ID = IC.ITEMSUBCATEGORY1
                           AND ISUB.ITEMSUBCATEGORY1ID IN
                               (SELECT ITEMSUBCATEGORY1ID
                                  FROM ITEMSUBCATEGORY1
                                 WHERE ITEMCATEGORYID = IV_ITEMCATEGORY)
                         INNER JOIN STORE SE
                            ON SE.STORECODE = R.STORECODE
                         WHERE R.STORECODE = IV_STORECODE
                           AND SE.HOSPITALID = IV_HOSPITALID
                           AND TRUNC(R.CREATEDDATE) BETWEEN V_FROMDATE AND
                               V_TODATE
                           AND R.STATUSID NOT IN (99, 5)
                              AND
                               (IV_DRUGTYPE IS NULL OR
                               IC.DRUGTYPECATEGORYID = IV_DRUGTYPE)
                        UNION
                        SELECT IV_STORECODE AS STORECODE,
                               TO_CHAR(STD.ITEMCODE) AS ITEMCODE,
                               C.ITEMCATEGORYNAME,
                               ISUB.ITEMSUBCATEGORY1NAME
                          FROM STOCKTRANSACTION ST
                         INNER JOIN STOCKTRANSACTIONDETAILS STD
                            ON ST.STOCKTRANSACTIONID = STD.STOCKTRANSACTIONID
                         INNER JOIN ITEMCOMPANY IC
                            ON IC.ITEMCODE = STD.ITEMCODE
                         INNER JOIN ITEMCATEGORY C
                            ON IC.ITEMCATEGORY = C.ITEMCATEGORYID
                          LEFT OUTER JOIN ITEMSUBCATEGORY1 ISUB
                            ON ISUB.ITEMSUBCATEGORY1ID = IC.ITEMSUBCATEGORY1
                           AND ISUB.ITEMSUBCATEGORY1ID IN
                               (SELECT ITEMSUBCATEGORY1ID
                                  FROM ITEMSUBCATEGORY1
                                 WHERE ITEMCATEGORYID = IV_ITEMCATEGORY)
                         INNER JOIN STORE SE
                            ON SE.STORECODE = ST.STORECODE
                         WHERE ST.STORECODE = IV_STORECODE
                           AND SE.HOSPITALID = IV_HOSPITALID
                           AND TRUNC(ST.CREATEDDATE) BETWEEN V_FROMDATE AND
                               V_TODATE
                           AND ST.STATUS <> 99
                           AND STD.ITEMCODE NOT LIKE '%#%'
                           AND
                               (IV_DRUGTYPE IS NULL OR
                               IC.DRUGTYPECATEGORYID = IV_DRUGTYPE)
                        UNION
                        SELECT D.STORECODE,
                               TO_CHAR(D.ITEMCODE) AS ITEMCODE,
                               C.ITEMCATEGORYNAME,
                               ISUB.ITEMSUBCATEGORY1NAME
                          FROM DAILYINVENTORY D
                         INNER JOIN ITEMCOMPANY IC
                            ON IC.ITEMCODE = D.ITEMCODE
                         INNER JOIN ITEMCATEGORY C
                            ON IC.ITEMCATEGORY = C.ITEMCATEGORYID
                          LEFT OUTER JOIN ITEMSUBCATEGORY1 ISUB
                            ON ISUB.ITEMSUBCATEGORY1ID = IC.ITEMSUBCATEGORY1
                           AND ISUB.ITEMSUBCATEGORY1ID IN
                               (SELECT ITEMSUBCATEGORY1ID
                                  FROM ITEMSUBCATEGORY1
                                 WHERE ITEMCATEGORYID = IV_ITEMCATEGORY)
                         INNER JOIN STORE SE
                            ON SE.STORECODE = D.STORECODE
                         WHERE D.STORECODE = IV_STORECODE
                           AND SE.HOSPITALID = IV_HOSPITALID
                           AND TRUNC(D.UPDATEDDATE) <= V_TODATE
                           AND D.QTY > 0
                           AND D.ITEMCODE NOT LIKE '%#%'
                           AND C.ITEMCATEGORYID = IV_ITEMCATEGORY
                              AND (IV_DRUGTYPE IS NULL OR
                               IC.DRUGTYPECATEGORYID = IV_DRUGTYPE)
                           AND (IV_SUBITEMCATEGORY IS NULL OR
                               ISUB.ITEMSUBCATEGORY1ID = IV_SUBITEMCATEGORY) Will post the explain plan ..
Thanks in advance..

Ensure you also include all the other information people will need to help you, e.g. database version, table structures/relationships and cardinalities, row counts etc.
See the two threads linked to in the FAQ: {message:id=9360003}

Is there any tool to analyze explain plan and gives the report

Hi All,
Is there any tool/scripts to analyze explain plan from plan_table and gives the output report
Thanks,
Sankar

Hi Jaffar,
Thank you!!!
The below query will generate the execution tree:
SELECT OPERATION,
     OPTIONS OPTIONS,
DECODE(TO_CHAR(ID),'0','---',OBJECT_NAME) OBJECT_NAME,
     (ID ||'-'|| NVL(PARENT_ID,0) ||'-'|| NVL(POSITION,0) ) "ID**PARENT_ID**EXECUTION_STEP",
     SUBSTR(OPTIMIZER,1,8) OPT
FROM PLAN_TABLE
START WITH ID = 0
AND STATEMENT_ID = 'Q1'
CONNECT BY PRIOR ID = PARENT_ID
AND STATEMENT_ID = 'Q1'
Thanks,
Sankar

Explain plan for query

HI all
Please help to evaluate the explian plan for query suppose the following is the plan
| Id | Operation                        | Name             | Rows | Bytes | Cost (%CPU)| Time     |
|   0 | SELECT STATEMENT                 |                  |     7 | 1260 |   303   (1)| 00:00:04 |
|   1 | SORT ORDER BY                   |                  |     7 | 1260 |   303   (1)| 00:00:04 |
|* 2 |   FILTER                         |                  |       |       |            |          |
|   3 |    NESTED LOOPS                  |                  |       |       |            |          |
|   4 |     NESTED LOOPS                 |                  |     7 | 1260 |   302   (1)| 00:00:04 |
|   5 |      NESTED LOOPS                |                  |     7 |   791 |   281   (1)| 00:00:04 |
PLAN_TABLE_OUTPUT
|* 6 |       TABLE ACCESS BY INDEX ROWID| TASKDETAIL       |     7 |   574 |   267   (1)| 00:00:04 |
|* 7 |        INDEX SKIP SCAN           | IDX_TD_TTS       | 2726 |       |    29   (0)| 00:00:01 |
|* 8 |       TABLE ACCESS BY INDEX ROWID| ORDERS           |     1 |    31 |     2   (0)| 00:00:01 |
|* 9 |        INDEX UNIQUE SCAN         | PK_SYS_C004711   |     1 |       |     1   (0)| 00:00:01 |
|* 10 |      INDEX RANGE SCAN            | TEPS_PICK_INDEX1 |     1 |       |     2   (0)| 00:00:01 |
|* 11 |     TABLE ACCESS BY INDEX ROWID | TASK_PICK_EPS    |     1 |    67 |     3   (0)| 00:00:01 |
-----------------------------------------------------------------------------------------------------1. what are the columns rows ,bytes,cost ,time indicate us

The current 11.2 version of the documentation (URL below) would be better than the 9.2 version
http://docs.oracle.com/cd/E11882_01/server.112/e16638/ex_plan.htm#i19260
"Rows" is the expected number of rows that will be returned by that step of the plan
"Bytes" is the expected size of the result set returned by that step of the plan
"Time" is the expected execution time --- this can be grossly off because Oracle uses some assumptions about singe block read time, multiblock read time and CPU speed.
Hemant K Chitale
Edited by: Hemant K Chitale on Sep 25, 2012 3:04 PM

General queries regarding explain plan and query

Similar Messages

Maybe you are looking for