25: Performance Tuning in Software

Create Code 39 Full ASCII in Software 25: Performance Tuning

25: Performance Tuning
Reading Code 3 Of 9 In None
Using Barcode Control SDK for Software Control to generate, create, read, scan barcode image in Software applications.
Painting Code 39 Full ASCII In None
Using Barcode creator for Software Control to generate, create Code 3/9 image in Software applications.
TIP While an index rebuild is in progress, additional storage space is required; plan ahead to make sure it is available The syntax of the REBUILD command has several options The more important ones are TABLESPACE, ONLINE, and NOLOGGING By default, the index will be rebuilt within its current tablespace, but by specifying a tablespace with the TABLESPACE keyword, it can be moved to a different one Also by default, during the course of the rebuild the table will be locked for DML This can be avoided by using the ONLINE keyword The NOLOGGING keyword instructs Oracle not to generate redo for the index rebuild operation This will make the rebuild proceed much faster, but it does mean that the tablespace containing the index should be backed up immediately Until the tablespace is backed up, the index will not survive media damage requiring use of restore and recovery EXAM TIP NOLOGGING disables redo generation only for the index rebuild; all subsequent DML against the index will generate redo as normal Unless ONLINE is specified, the table will be locked for DML while the rebuild is going on TIP Rebuilding indexes may also be necessary as part of normal database administration Indexes become inefficient with time particularly if there are many deletions, or updates that affect the key values of rows Exercise 25-4: Repair Invalid Objects and Unusable Indexes exercise, you will create some objects, break them, and repair them 1 Using SQL*Plus, connect to your database as user SYSTEM 2 Create a table to be used for the exercise:
Decode USS Code 39 In None
Using Barcode recognizer for Software Control to read, scan read, scan image in Software applications.
Make USS Code 39 In Visual C#.NET
Using Barcode encoder for VS .NET Control to generate, create Code 39 Full ASCII image in Visual Studio .NET applications.
create table valid_t as select * from all_users;
Draw Code 3 Of 9 In Visual Studio .NET
Using Barcode drawer for ASP.NET Control to generate, create Code 3/9 image in ASP.NET applications.
Drawing Code 39 Extended In VS .NET
Using Barcode printer for .NET Control to generate, create Code39 image in VS .NET applications.
PART III
Code 3/9 Generation In Visual Basic .NET
Using Barcode encoder for .NET framework Control to generate, create Code 39 Full ASCII image in Visual Studio .NET applications.
Create Bar Code In None
Using Barcode generation for Software Control to generate, create bar code image in Software applications.
In this
Creating Barcode In None
Using Barcode generator for Software Control to generate, create bar code image in Software applications.
Paint UPC Code In None
Using Barcode generator for Software Control to generate, create UPC-A Supplement 5 image in Software applications.
3 Create some objects dependent on this table:
Print DataMatrix In None
Using Barcode generation for Software Control to generate, create Data Matrix 2d barcode image in Software applications.
Generating Code 128 Code Set A In None
Using Barcode drawer for Software Control to generate, create Code 128A image in Software applications.
create create create insert end; / index valid_i on valid_t (username); view valid_v as select * from valid_t; procedure valid_p as begin into valid_t values ('name',99,sysdate);
Generate ISSN - 10 In None
Using Barcode printer for Software Control to generate, create ISSN image in Software applications.
Generate Code39 In Objective-C
Using Barcode generator for iPhone Control to generate, create Code 39 Full ASCII image in iPhone applications.
4 Confirm the status of the objects:
UPC A Encoder In Java
Using Barcode generation for Android Control to generate, create UPC-A image in Android applications.
Encode GTIN - 13 In None
Using Barcode drawer for Office Word Control to generate, create EAN-13 Supplement 5 image in Word applications.
select object_name,object_type,status from user_objects where object_name like 'VALID%'; select status from user_indexes where index_name ='VALID_I';
Paint Bar Code In Objective-C
Using Barcode creator for iPhone Control to generate, create bar code image in iPhone applications.
Code 128 Code Set B Scanner In Visual Studio .NET
Using Barcode decoder for .NET Control to read, scan read, scan image in VS .NET applications.
OCA/OCP Oracle Database 11g All-in-One Exam Guide
Printing UCC-128 In Visual Studio .NET
Using Barcode maker for .NET framework Control to generate, create EAN128 image in .NET framework applications.
EAN13 Drawer In Java
Using Barcode printer for Java Control to generate, create EAN 13 image in Java applications.
They will all have the STATUS of VALID Steps 2, 3, and 4 are shown here:
5 Perform the DDL command on the table that will break the objects:
alter table valid_t drop column created; alter table valid_t move;
6 Rerun the queries from Step 4 Note that the procedure and the view are now INVALID, and the index is UNUSABLE 7 Attempt to use the invalid objects:
execute valid_p; select * from valid_v;
8 Attempt to correct the errors:
alter view valid_v compile; alter procedure valid_p compile; alter index valid_i rebuild online nologging;
The compilations will fail, because the table has been changed, but the index will rebuild: it was never INVALID, merely UNUSABLE because the table move had changed all the rowids 9 Correct the errors by adding the column back to the table:
alter table valid_t add (created date);
10 Repeat Step 7 The statements will succeed
25: Performance Tuning
11 Rerun the queries in Step 4 All the objects are fine now, because the attempts to use them forced an automatic recompilation 12 Tidy up by dropping the objects:
drop table valid_t; drop procedure valid_p; drop view valid_v;
Database Replay
Changes occur in your software and hardware environment, whether it be upgrades to operating system, database, or application software or increasing the number of CPUs Less desirable changes may also occur: due to budgetary constraints, the server hosting your database may soon be part of a consolidation effort and new applications will be added to the server In any case, you need to measure the impact of these changes Database Replay will help to assess the change in performance on a test system by capturing the workload on the production server, and then replaying the workload on the test system This way you can resolve performance problems and ensure that the new production environment will still run your database applications with the same results as the old production system, before the change is implemented Using Database Replay consists of four main steps: 1 Workload capture 2 Workload preprocessing 3 Workload replay 4 Analysis and reporting
Copyright © OnBarcode.com . All rights reserved.