How to distribute the datafiles among various disks of a server, so that I/O operations are improved.
I mean is there any area we need to focus while distributing the disk like:
1)Particular types of datafiles should be placed in one disk.
2)Temp/Undo/Rollback tablespaces in another disk.
3)Indexes in another disk
I have a query optimized as to it indexes and others runs immediately when the answer is few records in SQL Server such as Oracle, however when the result is large eg 20,000 records all data access times are very diferent. The query returns many fields (about 20) and some of them are of type Varchar 250 and some of 2000 I understand here may be the problem, but not is because for similar results (20,000 records) sql run in 2 seconds and Oracle but it responds little to have full data takes around 30 seconds. The problem is really in bringing information to all these fields since if the inquiry it also but only returning a numeric field is done in 2 seconds. Tests I've done them both through ODBC, in the Toad as in the own Oracle console on the server, so it is not problem Driver or flow of data through the network, I would like to think that this is some of the settings I think there is as much difference between Oracle and Sql. The databases are ORACLE 10 and SQL Server 2008.
View 1 Replies View RelatedFew days ago, My database server no access to StorageBox then I reboot it then after works fine. But, know DB import process is too slow. Before 100GB DB import process completed within 10 hours when server normal running. Now 2 day working, but not complete
How to investigate this issue? Maybe I miss increase some parameters on the Server or Oracle?
Here is my server brief info:
RAM is 16GB,
SWAP size is 16GB,
CPU 12 cores
SQL> show sga;
Total System Global Area 4294967296 bytes
Fixed Size 1984144 bytes
Variable Size 369105264 bytes
Database Buffers 3909091328 bytes
Redo Buffers 14786560 bytes
Looking to understand the difference between instance tuning and database tuning.
What is the difference between these two tuning exercises? I understand that an instance is memory based structures (logical) where as database consists of physical structures.
However, how does one tune a database the physical structure? Does it have to do with file placements/block sizes etc. Would you agree that a lot of that is taken care by ASM now in 11g? What tools are required/available (third party as well as oracle supplied) for these types of tuning scenarios?
I ran a scp command to transfer a file from local server to a remote server. when I am trying to kill the process, its giving an error.
ksh: kill: 19258: No such process
If I do a ps -ef | grep scp its showing the process running, but if i try to kill it, its showing me error.
I have a procedure which mainly run queries on a Table which has nearly 9.5 million recodes. This procedures takes nearly 15 min to complete execution on our main database. I exported and imported the schema to our backup database and the same procedure just took 3 seconds to complete.
I tried to analyze the table in our main database and tried to execute the procedure again but did not show any improvements. ANALYZE TABLE DN_ACTIONS COMPUTE STATISTICS;
I am not sure computing the statistics for all the tables in the schema will work. I also checked there is enough disk space where oracle data files are stored. I am also turning on the sql trace to see what sql statements in the procedure is taking longer time.
how would we learn creating workspaces on the production server for application services:
* Folder structure
* How client workspaces are sharing other common folders, tomcat, java, software release etc
* Scripts tomcat and create54workspace
I have two tables with 113M records in DWH_BILL_DET & 103M in prd_rerate_chg_que and Im running following merge query, which is running for 13 hrs to update records, which is quiet longer time.
SQL> explain plan for MERGE /*+ parallel (rq, 16) */
INTO DWH_BILL_DET rq
USING (SELECT rated_que_rowid,
detail_rerate_flag_code,
rerate_sel_key,
[code].....
How the length of column width effects index performance?
For example if i had IOT table emp_iot with columns:
(id number,
job varchar2(20),
time date,
plan number)
Table key consist of(id, job, time)
Column JOB has fixed list of distinct values ('ANALYST', 'NIGHT_WORKED', etc...).
What performance increase i could expect if in column "job" i would store not names but concrete numbers identifying job names.
For e.g. i would store "1" instead 'ANALYST' and "2" instead 'NIGHT_WORKED'.
I have a question about database fragmentation.I know that fragmentation can reduce performance in query times. The blocks are distributed in many extents and scans process takes a long time. Oracle engine have to locate the address of the next extent..
I want to know if there is any system view in which you can check if your table or index has high fragmentation. If it's needed I will have to re-create, move or rebulid the table or index, but before I want to know if the degree of fragmentation is high.
Any useful script or query to do this, any interesting oracle system view?
There is a simple way to increase the performance of a query by reducing the row-size of the table it hits. I used it in the past by dividing the table into smaller parts and querying respective smaller table in each query.
what is this method called ? just forgot the method and can't recall it. what this type of row-reduction optimization is called ?
How many records could I have in a single table without performance degradation with Standard Edition without partitioning with cutting-edge server (8 or 12 cores, 72 GB RAM, FC 4 Gbit, etc...) and good storage?
300 Millions in only one table with 500K transactions / day is too much?
Simple database with simple schema.
How many records begin to be too many?
Testing our 9i to 11g upgrade, we've imported the entire DB into the new machine.We've found that certain procedures are really suffering performance problems. BUT, we've also found, that if we check out a production copy of the procedure from our source code control, and reinstall it, the performance issue goes away. Just alter the procedure and recompiling does NOT work.
The new machine where the 11g database exists is slightly different than the source, but it's not like we have this problem with every procedure. It's only a couple.
any possible reason that we'd have to re-install a procedure to correct a performance problem?
I need to check the package performance and need to improve the package performance.
1. how to check the package performance(each and every statement in the package)?
2. In the package using the delete statement to delete all records and observed that delete is taking long time to delete all the records in the table(Table records 7000000). This table is like staging table.Daily need to clean the data before inserting the data into it. what can I use instead of Delete.
Somewhere I read that we should not use hints in Oracle production environments, but we can use hints in the development environment and on achieving the desired execution plan we can adjust the 'statistics' to follow that plan without hints.
Q1. If it is true what statistics do we adjust for influencing the execution plan and how?
For example, I have the following simple query:
select e.empid, e.ename, d.dname
from emp e, dept d
where e.deptno=d.deptno;
emp.empid, emp.deptno and dep.deptno columns have indexes and the tables have the standard structure as found in the basic oracle examples.
If I look at the execution plan of the above query then I see that the driving table is empand the driven table is dept.Also the type of join that is taking place is 'Nested Loop'.
Questions: With respect to the above query,
Q 2. If I want to make dept the driving table and emp the driven table then how can I adjust the statistics to achieve that?
Q 3. If I want to use hash join instead of a nested loop join then then how can I adjust the statistics to achieve that?
I can put the ordered and the use_hash hint to effect this but again I have heard that altering statistics is a more robust way to control an execution plan as compared to hints.
I have an issue with export(expdp).
When i exporting an user using expdp utility, the load the on the server is going up-to 5. The size of the database is 180GB. Below is the command that i use for export.
expdp sys/xxxx directory=dbpdump dumpfile=expdp_trk_backup.dmp logfile=expdp_trk_backup.log exclude=statistics schemas=trk
Do i need any look into any memory parameters for this?
Due to improper documentations of a certain project, I need to drop a DEFAULT tablespace of a newly created instance including it's associated datafiles by using this command:
"DROP TABLESPACE <tablespace name> INCLUDING CONTENTS AND DATAFILES;"
The default tablespace name is QWER (qwer01.dbf) and I added 2 datafiles in it, re: OPD_SML01.dbf & EXYT_SML01.dbf.
Do I have to do it online or offline?
Can we add a datafile mapped to a shared network drive in windows server.
View 1 Replies View RelatedJust noticed MR(media recovery lock ) in our database,further check showd all datafiles had this lock since our database was shutdown abortly but was startup gracefully.
View 2 Replies View RelatedWhat is best practice to change small disk D:? I am beginner with Oracle. 10g on W2008. 5 datafiles (all indexes,second data file, 2 undotabs)*.dbf (34;30;1;34;12 GB) is on D:. Part of tablespaces (1 data, 1 undo)has files on c:.
I.
1.Shutdown 2008 server.
2.Copy D: image with GHOST to USB, network.
3.Connect new D, create RAID.
4.Restore image to D.
5.Start 2008 server.
II.
1.Stop application.
2.CONNECT AS SYSDBA
3.SHUTDOWN NORMAL or (IMMEDIATE)?
4.Copy files *.dbf at OS level from d: to ... USB disk, network.
5.Shutdown 2008 server.
6.Change disks, create RAID in BIOS.
7.Start W2008.
Is Oracle at this moment in SHUTDOWN mode?
8.Copy back *.dbf to new D: (with directory structure).
9.STARTUP Oracle.
i encoutered lately on such statement:
Table D-7 shows a hierarchical file mapping of a sample OFA-compliant installation with two Oracle home directories and two databases. The database files are distributed across three mount points, /u02, /u03, and /u04. URL....
why three mount points (/u02, /u03, and /u04) for datafiles? don' understant this. isn't it better to store all datafiles in one mountpoint?
I have checked the space of my tablespaces/datafiles in my database. I have 8 GB space left in my database server. I cant add more hard-disk as there is no slot left. We r planning to buy a new server with latest config.
My question is, how can we know upto what size our database can increase and when a datafile need to be added in advance. Sometimes even though datafiles have space left,it shows errors abt extents cannot be extended. We have coalesce the tablespaces and added a new datafile.
I am facing an issue while rebuilding a DR (Physical Standby) site using RMAN.Rman is failing to restore all the datafiles to the stanby site.
There are 403 datafiles that should be restored among which after restoring 50-60 datafiles the channel is abruptly getting terminated.Please note this exercise is not new I have done this many times (once a year after a DR testing) and the same script is being used.The rcv file is as follows
/u03/oracle/admin/mpr/scripts/dataguard/configure_dr.rcv
connect auxiliary sys/XXXX@YYY
run {
duplicate target database for standby nofilenamecheck dorecover;
}
exit
CONFIGURE DEVICE TYPE DISK PARALLELISM 1 BACKUP TYPE TO BACKUPSET;
configure_dr.rcv: END
[code]....
The trace file says "krso_proc_add: Detected dead process 13828326; subsuming V$MANAGED_STANDBY slot
INFO: krsr_rfs_atc: RFS processes are temporarily disallowed"
I have also started RMAN debug tracing and the trace is also scanned as it is huge.I have seen the following in the trace error 3015 signalled during compilation..I do not find any specific oracle error to check on .
The only change that happened is that the Primary production server has been moved to a new datacentre and after its move all the connections seems to be working fine.
We have two tablespace xyz_ts & pqr_ts having 167 datafiles . We have to reduce this number of files. These tablespace having 580 GB size .
View 1 Replies View Related would want to check which tables located in which datafiles.
Tried with this command:
select B.FILE_NAME from dba_segments a, dba_data_files b
where a.header_file=b.file_ID and segment_name='TABLE_NAME'
Seems like it only shows 1 datafile. Some tables are large and i suppose it's resided in more than 1 datafile.
what's the difference between having BIG datafile (32GB) vs many small datafiles (4GB) replacing a Big one.
View 3 Replies View RelatedWe have lost some datafiles and some archivelogs. We have backup of whole database taken on Dec 20 and archivelogs until Dec 23.So we dont have 1 day worth of archivelogs which can lead to incomplete recovery.
Now question is do we need to restore all datafiles or only lost datafiles for incomplete recovery since we dont have all archivelogs ? lost datafiles belong to different tablespaces.
Datafiles which are still intact are with current SCN and we restore lost datafiles only and recover unitl our last available archivelog it will have different SCN. Will we be able to open database or we need to resotre whole database for this scenario?
The following query gets input parameter from the Front End application, which User queries to get Reports.There are many drop down boxes like LOB, FAMILY, BRAND etc., The user may or may not select values from drop down boxes.
If the user select any one or more values ( against each drop down box) it has to fetch all matching values from DB. If the user does'nt select any values it has to fetch all the records, in this case application will send a value 'DEFAULT' (which is not a value in DB ) so that the DB will fetch all the records.
For getting this I wrote a query like below using DECODE, which colleague suggested that will hamper performance.From the below query all the variables V_ are defined in procedure which gets the values selected by user as a comma separated string here V_SELLOB and LOB_DESC is column in DB.
DECODE (V_SELLOB, 'DEFAULT', V_SELLOB, LOB_DESC) IN
OPEN v_refcursor FOR
SELECT /*+ FULL(a) PARALLEL(a, 5) */
*
FROM items a
WHERE a.sku_status = 'A'
[code]...
what the principal things to look at when we have for the same query different performance results are?I have 2 different bases: the plan and data are the same but performance results are very differents.
View 10 Replies View RelatedI am looking for a script to find the tbs usage including datafiles. Tablespaces Datafile Size Used Free Used% Free% Max MB
Need all the data in MB and all the datafile space in every tablespace.I have searched internet,but couldn't find this type of format.