IT Answers » Oracle performance

Strange Oracle 9i behaviour

Darryn — Thu, 10 Mar 2011 13:43:32 +0000

We are seeing some very strange behaviour in the performance of a query on our database. We have run the same query on the actual database server (s1) using sql+, and on a server (s2) 1 hop away (taking out network performance). The exact same queries, without any bind variables, are kicked off at exactly the same time. The query that is run on the s1 finishes in 30-40 minutes, whilst the query that is run from s2 takes 4 hours to finish. Even when the queries are started at different times during the day, no matter in which order, or only 1 at a time, the s1 query always takes less than an hour, whilst the s2 query always takes close on 4 hours. The explain plans for both sessions show the exact same paths, however, they have different costs (I believe this is due to a logon trigger that is forcing the optimizer_index_cost_adj = 10 when the s2 session is created). The OS user used to log in to s1 does not have any specific resource rights.

It has been noted that there are a lot of waits between reads for client side queries, which don’t seem to be happening on the server side query. The session statistics don’t really tell us much, other than that it is taking a lot longer to run.

Is this behaviour normal for server vs client queries? Does it make a difference that the costs are higher in the explain plan generated, even though the steps are exactly the same? If not, what else can we look at?

Terminate SQL exception, if it is running more than a specified time.

Liveena — Mon, 15 Nov 2010 10:03:03 +0000

Whether we can forcefully terminate an sql statement during its execution if it is running for a long time or running more than a specified time?

Tunning and Performance in Oracle 8i

ITKE — Fri, 14 Aug 2009 14:31:23 +0000

we have a 20 users accessing application of vb and database is oracle
8i from morning server runs fine till after noon it slow down then we
need ot restart the database then again for an hour it works fast but
again it gets slow donw can you please suggest what to do ???

How to determine the number of concurrent processes in Oracle 10g

DBASAB — Mon, 08 Jun 2009 10:50:44 +0000

How can I find out the number of concurrent processes at any point of time in 10g database

Windows performance setting for Oracle

NormD — Wed, 13 May 2009 17:17:14 +0000

We are looking at our db performance (10gR2 on Win 2003 SP2) and am wondering what setting would give the better performance for the db. The server is only hosting the oracle backend for BMC Remedy 7.1p6. Its a DL580 with 8GB ram.

The factors I’m looking at at the OS level is:
- Paging: system managed or
- Processor scheduling: Programs or Background services

- Memory usage: Programs or System cache
- File paging: Custom and size, System managed, None

Thanks
Norm

How number of processors correlated to Oracle database size

626 — Mon, 20 Apr 2009 21:16:34 +0000

Is there a guideline to determine how many processors to use (in unix OS) according to the Oracle database size?

Oracle SQL*Loader (sqlldr) performance tuning

Ws8oBPSQ — Tue, 09 Dec 2008 06:48:34 +0000

Good day,

I try to optimize sqlldr, but don’t know how to set the parameters. I am trying to load 21,000,000 records per day, but currently don’t manage to load all data in time. The loading is always 1 day behind. I am using conventional loading (I cannot disable indexes before and after loading, because of users accessing tables during the day and the time it will take to rebuild indexes). The table contains data for 1 and 1/2 month only with already 800,000,000 records. Each record contains 180 columns.
What will the best sizes be to set the following parameters:
bindsize, rows, columnarrayrows, readsize.
Currently I did not set any parameters. Am using defaults only. Each file to load contains 28,000 records. It took +- 4 minutes to load a file into 4 oracle database tables.
Regards
Bonita

Oracle Statspack

Jwwolff — Wed, 03 Dec 2008 20:26:51 +0000

I recently started running statspack on my Oracle 9.2.0.7 database so I can get concrete evidence of what is going on in my database, besides viewing it through the grid. I started up statspack on Monday at 5pm and told my director that I’d turn is off at 5pm the next day. I did not turn it off and was yelled at quite thoroughly today because of the perceived extra load statspack put on the database. My mgr & director both think it puts extra strain on the database and that I either shouldn’t run it at all or that I should wait till lighter load days like Friday or the weekend.

I always thought that it did not affect performance at all and was a task that ran in the background. Am I misguided?

Thanks for your input.
James Wolff

Need to update nearly 3cr rows in Oracle table

AGDAVA — Thu, 13 Nov 2008 02:14:52 +0000

HI ,
My database is oracle 8.0 vesion.i need to update the customer_id in in table with new_customer_id.

for the smaller table my simple update is working fine ..
when i fired the same update for the big tables ( 30000000 rows), its running for 10 hrs and failing with rollback segments.
can any one tell me what is the best way to complete this update.

they way i did for the samll table is

SQL> SELECT * FROM CUST_OLD;

CUST_ID NAME
——– ——–
111 AAA
222 BBB
333 CCC
444 DDD
111 AAA
222 BBB
555 EEE

7 rows selected.

SQL> SELECT * FROM CUST_NEW;

CUST_ID CUST_NEW
——– ——–
111 1111
222 2222
333 3333
444 4444
555 5555
666 6666
777 7777
888 8888
999 9999

SQL> UPDATE CUST_OLD A SET A.CUST_ID=
2 (
3 SELECT
4 B.CUST_NEW_ID
5 FROM
6 CUST_NEW B
7 WHERE
8 A.CUST_ID=B.CUST_ID
9 AND B.CUST_NEW_ID IS NOT NULL)
10 WHERE EXISTS
11 (SELECT C.CUST_ID FROM CUST_NEW C WHERE A.CUST_ID=C.CUST_ID) ;

7 rows updated.

SQL> SELECT * FROM CUST_NEW;

CUST_ID CUST_NEW
——– ——–
111 1111
222 2222
333 3333
444 4444
555 5555
666 6666
777 7777
888 8888
999 9999

9 rows selected.

SQL> SELECT * FROM CUST_OLD;

CUST_ID NAME
——– ——–
1111 AAA
2222 BBB
3333 CCC
4444 DDD
1111 AAA
2222 BBB
5555 EEE

7 rows selected.

Oracle9i Performance Issue

Stecjohn — Fri, 31 Oct 2008 23:15:08 +0000

I got Oracle9i R2 database running on windows 2003.
On a very busy day I got very bad performance with Average Disk Queue Length very high on the performance monitor. There is heaps of free RAM and I am running Raid 10.
I am still new to Oracle, so I need some help.
Thanks and regards.