Same query at same time, but different execution plans from two schemas

Hi!
We just had some performance problems in our production system and I would like to ask for some advice from you.
We had a select-query that was run from USER1 on SCHEMA1, and it ran a table scan on a huge table.
Using session browser in TOAD I copied the Sql-statement, logged on SCHEMA1 and ran the same query. I got a different execution plan where I avoided the table scan.
So my question is:
How is it possible that the same query get different execution plans when running in two different schemas at the same time.
Some more information:
The user USER1 runs "alter session set current_schema=SCHEMA1;" when it logs on. Besides that it doesn't do anything so session parameter values are the same for USER1 and SCHEMA1.
SCHEMA1 is the schema owning the tables.
ALL_ROWS is used for both USER1 and SCHEMA1
Our database:
Oracle9i Enterprise Edition Release 9.2.0.8.0 - 64bit Production
PL/SQL Release 9.2.0.8.0 - Production
CORE 9.2.0.8.0 Production
TNS for Linux: Version 9.2.0.8.0 - Production
NLSRTL Version 9.2.0.8.0 - Production
Anybody has some suggestions to why I experience different execution plan for the same query, run at the same time, but from different users?

Thanks for clarification of the schema structure.
What happens if instead of setting the current session schema to SCHEMA1, if you simply add the schema name to alle tables, views and other objects inside your select statement?
As in select * from schema1.dual;I know that this is not what you want eventually, but it might help to find any misleading objects.
Furthermore it is not clear what you meant with: "avoided a table scan".
Did you avoid a full table scan (FTS) or was the table completely removed from the execution plan?
Can you post both plans?
Edited by: Sven W. on Mar 30, 2010 5:27 PM

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The AWR reports for two days with same sqlID with different execution plan and Elapsed Time (s), Executions time please help me to find out what is reason for this change.
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You wrote with different execution plan, I think, you saw plans. It is very difficult, you get old plan.
I think Execution plans is not changed in different days, if you not added index or ...
What say ADDM report about this script?
As you know, It is normally, different Elapsed Time for same statement in different day.
It is depend your database workload.
It think you must use SQL Access and SQl Tuning advisor for this script.
You can get solution for slow running problem.
Regards
Mahir M. Quluzade

Same Query returning different result (Different execution plan)

Hi all,
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Thanks.

H.Mahmoud wrote:
Oracle version : 9.2.0.2.0
System version : HP-UX v1Hard to say. You're using a very old and deprecated version of the database, and one that was known to contain bugs.
9.2.0.7 was really the lowest version of 9i that was considered to be 'stable', but even so, it's old and lacking in many ways.
Consider upgrading to the latest database version at your earliest opportunity. (or at least apply patches up to the latest 9i version before querying if there is bugs in your really low buggy version)

Same query with different execution plan

Hello All,
I wonder why does sql server create different execution plan for these below queries ?
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You can look at the expected query plan. Either visually in SSMS, or alternatively, you can run the query after the instruction SET SHOWPLAN_TEXT ON.
The Optimizer is the component of SQL Server that determines how the query is executed. It is cost based. It will assess different execution plans, estimate the cost of each of them and then select the cheapest. In this context, cheapest means the one with
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In the first query, it estimated that looking up the many qualifying rows there would be too expensive, and that it would be cheaper to simply scan the entire clustered index, and simply filter out all unwanted rows. Note that the clustered index includes
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Can anybody explain, why the same query shows two different plans at the same time ?
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Aalap Sharma wrote:
HP-Ux
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We are experiencing a strange issue. One of our night batch process is taking invariably more time to execute. The process does not consume time at 1 particular query. Everyday we find a new query taking more time than previous execution.
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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/

Re: Running the same (Forte) application multiple times -for different

Hi
We had the same problem - how to deploy a number of identical applications, using each their own db.
(for training).
The solution we used is to wrap the entire application into different applications by using a very small
module called KURSUS01, KURSUS02 etc, that did nothing but call the start procedure of the main app.
Then in the dbsession connect, we made a call appname to get the application name, and appended the
first 8 chars to the dbname. Thus our dbnames now points to logicals name: rdbdataKURSUS01, rdbdataKURSUS02 etc.
All this allows us to deploy the identical apps in the same env, or change one version, and run both the old
and new program on the same pc and server at the same time (eg. KURSUS01 and KURSUS02).
I also think this is a kludge - but it works nicely!
Jens Chr
KAD/Denmark
-----Original Message-----
From: Haben, Dirk <[email protected]>
To: 'Soapbox Forte Users' <[email protected]>
Date: 15. januar 1999 09:41
Subject: Running the same (Forte) application multiple times - for different business clients.
Hi All
We have a number of different business clients all willing to use our
application.
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clients.
All (business) clients will have their data kept in separate Oracle DBs
(instance).
The problem now is that the entire (forte) application is written using
DBSessions.
Now, depending on what business client needs to be serviced (so to speak) we
need to attach to the right DB - or use the "right" SO.
The two options we can think of are:
Option1:
Programatic change to somehow "know" what (business) client (DB) I'm talking
about and then use the right DB.
Pro:
Only one forte environment to maintain
Can run multiple (business) clients on same PC at the same time
Con:
Requires many program changes
bending O-O rules(?)
can't dynamically name SOs so can it be done at all? (ResourceMGRs maybe?)
Option2:
Use separate environments! One for each business client.
Pro:
More defined separation of app and data,
SLA-easy
Con:
Maintain "n" number of environments
Can only run the application for one environment (business client) at a time
on one PC - Big Negative here!
Not knowing any feasible solution to option 1 (without much code changes and
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multi-environment setups on VMS back at the Hydro (hi guys).
I would appreciate any comments from anyone who has solved this problem.
How, Why Pro Con etc.
TIA,
Dirk Haben
Perth, WA
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Hi
We had the same problem - how to deploy a number of identical applications, using each their own db.
(for training).
The solution we used is to wrap the entire application into different applications by using a very small
module called KURSUS01, KURSUS02 etc, that did nothing but call the start procedure of the main app.
Then in the dbsession connect, we made a call appname to get the application name, and appended the
first 8 chars to the dbname. Thus our dbnames now points to logicals name: rdbdataKURSUS01, rdbdataKURSUS02 etc.
All this allows us to deploy the identical apps in the same env, or change one version, and run both the old
and new program on the same pc and server at the same time (eg. KURSUS01 and KURSUS02).
I also think this is a kludge - but it works nicely!
Jens Chr
KAD/Denmark
-----Original Message-----
From: Haben, Dirk <[email protected]>
To: 'Soapbox Forte Users' <[email protected]>
Date: 15. januar 1999 09:41
Subject: Running the same (Forte) application multiple times - for different business clients.
Hi All
We have a number of different business clients all willing to use our
application.
The (forte) application is to run on our machines etc for these (business)
clients.
All (business) clients will have their data kept in separate Oracle DBs
(instance).
The problem now is that the entire (forte) application is written using
DBSessions.
Now, depending on what business client needs to be serviced (so to speak) we
need to attach to the right DB - or use the "right" SO.
The two options we can think of are:
Option1:
Programatic change to somehow "know" what (business) client (DB) I'm talking
about and then use the right DB.
Pro:
Only one forte environment to maintain
Can run multiple (business) clients on same PC at the same time
Con:
Requires many program changes
bending O-O rules(?)
can't dynamically name SOs so can it be done at all? (ResourceMGRs maybe?)
Option2:
Use separate environments! One for each business client.
Pro:
More defined separation of app and data,
SLA-easy
Con:
Maintain "n" number of environments
Can only run the application for one environment (business client) at a time
on one PC - Big Negative here!
Not knowing any feasible solution to option 1 (without much code changes and
developer moaning) I would go for option two; as I have already worked on
multi-environment setups on VMS back at the Hydro (hi guys).
I would appreciate any comments from anyone who has solved this problem.
How, Why Pro Con etc.
TIA,
Dirk Haben
Perth, WA
To unsubscribe, email '[email protected]' with
'unsubscribe forte-users' as the body of the message.
Searchable thread archive <URL:http://pinehurst.sageit.com/listarchive/>
To unsubscribe, email '[email protected]' with
'unsubscribe forte-users' as the body of the message.
Searchable thread archive <URL:http://pinehurst.sageit.com/listarchive/>

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Good afternoon,
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Edited by: scampsd on May 17, 2011 1:42 PM

scampsd wrote:
Good afternoon,
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At first (when the database has just been restarted), it looks like this:
At regular intervals a "coalesce" of the <INDEX2> is scheduled.
Do you have any idea what might cause this different plans? (it's heavily impacting performance, because the second execution plan takes 5 times more time)Something on your system is changing. Unfortunately if finding out what were easy you would have done it already
You have isolated a couple of things. What happends of you disable the index maintenance?
It is odd that performance as you described it degrands merely because of time the database has been up

Different 'execution plans' for same sql in 10R2

DB=10.2.0.5
OS=RHEL 3
Im not sure of this, but seeing different plans for same SQL.
select sql_text from v$sqlarea where sql_id='92mb4z83fg4st'; <---TOP SQL from AWR
SELECT /*+ OPAQUE_TRANSFORM */ "ENDUSERID","LASTLOGINATTEMPTTIMESTAMP","LOGINSOURCECD","LOGINSUCCESSFLG",
"ENDUSERLOGINATTEMPTHISTORYID","VERSION_NUM","CREATEDATE"
FROM "BOMB"."ENDUSERLOGINATTEMPTHISTORY" "ENDUSERLOGINATTEMPTHISTORY";
SQL> set autotrace traceonly
SQL> SELECT /*+ OPAQUE_TRANSFORM */ "ENDUSERID","LASTLOGINATTEMPTTIMESTAMP","LOGINSOURCECD","LOGINSUCCESSFLG",
"ENDUSERLOGINATTEMPTHISTORYID","VERSION_NUM","CREATEDATE"
FROM "BOMB"."ENDUSERLOGINATTEMPTHISTORY" "ENDUSERLOGINATTEMPTHISTORY"; 2 3
1822203 rows selected.
Execution Plan
Plan hash value: 568996432
| Id | Operation | Name | Rows | Bytes | Cost (%CPU)| Time |
| 0 | SELECT STATEMENT | | 1803K| 75M| 2919 (2)| 00:00:36 |
| 1 | TABLE ACCESS FULL| ENDUSERLOGINATTEMPTHISTORY | 1803K| 75M| 2919 (2)| 00:00:36 |
Statistics
0 recursive calls
0 db block gets
133793 consistent gets
0 physical reads
0 redo size
76637183 bytes sent via SQL*Net to client
1336772 bytes received via SQL*Net from client
121482 SQL*Net roundtrips to/from client
0 sorts (memory)
0 sorts (disk)
1822203 rows processed
===================================== another plan ===============
SQL> select * from TABLE(dbms_xplan.display_awr('92mb4z83fg4st'));
15 rows selected.
Execution Plan
Plan hash value: 3015018810
| Id | Operation | Name |
| 0 | SELECT STATEMENT | |
| 1 | COLLECTION ITERATOR PICKLER FETCH| DISPLAY_AWR |
Note
- rule based optimizer used (consider using cbo)
Statistics
24 recursive calls
24 db block gets
49 consistent gets
0 physical reads
0 redo size
1529 bytes sent via SQL*Net to client
492 bytes received via SQL*Net from client
2 SQL*Net roundtrips to/from client
0 sorts (memory)
0 sorts (disk)
15 rows processed
=========second one shows only 15 rows...
Which one is correct ?

Understood, second plan is for self 'dbms_xplan'.
Anyhow I opened a new session where I did NOT on 'auto-trace'. but plan is somewhat than the original.
SQL> /
PLAN_TABLE_OUTPUT
SQL_ID 92mb4z83fg4st
SELECT /*+ OPAQUE_TRANSFORM */ "ENDUSERID","LASTLOGINATTEMPTTIMESTAMP","LOGINSOURCECD","
LOGINSUCCESSFLG","ENDUSERLOGINATTEMPTHISTORYID","VERSION_NUM","CREATEDATE" FROM
"BOMB"."ENDUSERLOGINATTEMPTHISTORY" "ENDUSERLOGINATTEMPTHISTORY"
Plan hash value: 568996432
| Id | Operation | Name | Rows | Bytes | Cost (%CPU)| Time |
PLAN_TABLE_OUTPUT
| 0 | SELECT STATEMENT | | | | 2919 (100)| |
| 1 | TABLE ACCESS FULL| ENDUSERLOGINATTEMPTHISTORY | 1803K| 75M| 2919 (2)| 00:00:36 |
15 rows selected.
I am just wondering, which plan is the accurate and which I need to believe ?

Same Apple ID for iTunes, but different Windows accounts...

My wife and I use the same Apple ID for iTunes, but we have different Windows 7 accounts on the same computer. I've uploaded a pile of CDs. ITunes Match seems to match them ok, but she can't see them from iTunes on her account. We could upload the CDs twice, once for each account, but that's a wicked waste of time. Is there a workaround for this?

iTunes Match is associated with only one Apple ID and cannot be shared across Apple IDs. For your wife to make use of iTunes Match and see the music in the cloud she must login to your Apple ID on the iTunes Store and she will have to stay logged in. This may cause difficulty when updating apps purchased with her Apple ID.
Also keep in mind that a computer can only be associated with one Apple ID for iTunes Match, automatic downloads and re-downloading of content once every 90 days: http://support.apple.com/kb/HT4627.

Different execution plans for the same sql

Hi,
Im testing our new 10gR2 database on Linux and I can't understand why the same query use different plan.
Here are the details.
Table name: invoice_detail
Records: About 10,670,900
Columns:
No
seq (the primary key is No+Seq). Each invoices contains +/- 10 invoice_details.
category ( <- 10 different values )
State ( <- 3 different values )
Basically, I have an index on the primary key and another index on Category + State.
My request:
select *
from invoice_detail
where no=123456 <- Best index to use
and state <> 'CANCEL'
and category = 'INVOICE'
If i run this query from Toad or sql+, that's fine.
The same query (i'm watching it from EM) executed via Forms use the category+state index.
When I first import the database, the last thing I do is to run DBMS_STATS.GATHER_DATABASE_STATS.
At this point, Forms use the right index.
The day after (after the database has been analyzed with the predefined job via EM) Forms use the wrong index.
I re-analyzed everything with exec DBMS_STATS.GATHER_DATABASE_STATS but the problem is still there.
Thanks in advance

I'm already using bind variables.
I changed the "Estimated Percentage" to 100% in "Gather Optimizer Statistics Default Options" and now it seems to use the correct index. I'm stressed because I dont understand why it chooses different plan for the same sql.
Actually, my users test the migration 1 day after I load all the data (drop schema-create schema-load data-analyze database) and at this point everythings go fine. After the second analyze of the database, the DB choose the wrong indexes.
I really cannot migrate until I understand why it happens.
Any ideas?
TIA

Same query at same time, but different execution plans from two schemas

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