native barcode generator for crystal reports crack Investigating Redo in Objective-C

Generating Data Matrix ECC200 in Objective-C Investigating Redo

Investigating Redo
ECC200 Generation In Objective-C
Using Barcode generation for iPhone Control to generate, create DataMatrix image in iPhone applications.
www.OnBarcode.com
Printing GTIN - 128 In Objective-C
Using Barcode maker for iPhone Control to generate, create EAN128 image in iPhone applications.
www.OnBarcode.com
As a developer, it s often important to be able to measure how much redo your operations generate. The more redo you generate, the longer your operations may take, and the slower the entire system might be. You are not just affecting your session, but every session. Redo management is a point of serialization within the database. There is just one LGWR in any Oracle instance, and eventually all transactions end up at LGWR, asking it to manage their redo and COMMIT their transaction. The more it has to do, the slower the system will be. By seeing how much redo an operation tends to generate, and testing more than one approach to a problem, you can find the best way to do things.
Encode Barcode In Objective-C
Using Barcode encoder for iPhone Control to generate, create Barcode image in iPhone applications.
www.OnBarcode.com
Data Matrix ECC200 Generation In Objective-C
Using Barcode maker for iPhone Control to generate, create ECC200 image in iPhone applications.
www.OnBarcode.com
Measuring Redo
Encode Code-128 In Objective-C
Using Barcode creation for iPhone Control to generate, create Code 128A image in iPhone applications.
www.OnBarcode.com
Draw EAN-13 Supplement 5 In Objective-C
Using Barcode generator for iPhone Control to generate, create EAN 13 image in iPhone applications.
www.OnBarcode.com
It is pretty straightforward to see how much redo is being generated, as shown earlier in the chapter. I ve used the AUTOTRACE built-in feature of SQL*Plus. But AUTOTRACE works only with simple DML it can t, for example, be used to view what a stored procedure call did. I ve also used my utility function presented above, GET_STAT_VAL, to retrieve the redo size value from V$ tables. We ll continue to use that function for the following exercise. Let s take a look at the difference in redo generated by conventional path INSERTs (the normal INSERTs you and I do every day) and direct-path INSERTs used when loading large amounts of data into the database. We ll use AUTOTRACE and the previously created tables T and BIG_TABLE for this simple example. First we ll load the table using a conventional-path INSERT: ops$tkyte%ORA11GR2> set autotrace traceonly statistics; ops$tkyte%ORA11GR2> truncate table t; Table truncated. ops$tkyte%ORA11GR2> insert into t 2 select * from big_table;
Code39 Maker In Objective-C
Using Barcode printer for iPhone Control to generate, create Code 39 image in iPhone applications.
www.OnBarcode.com
Make UCC - 12 In Objective-C
Using Barcode creator for iPhone Control to generate, create Universal Product Code version E image in iPhone applications.
www.OnBarcode.com
CHAPTER 9 REDO AND UNDO
Data Matrix ECC200 Generation In None
Using Barcode printer for Font Control to generate, create Data Matrix ECC200 image in Font applications.
www.OnBarcode.com
ECC200 Creation In None
Using Barcode drawer for Software Control to generate, create Data Matrix ECC200 image in Software applications.
www.OnBarcode.com
1000000 rows created. Statistics ---------------------------------------------------------2963 recursive calls 133438 db block gets 44024 consistent gets 15218 physical reads 122853436 redo size 932 bytes sent via SQL*Net to client 1006 bytes received via SQL*Net from client 4 SQL*Net roundtrips to/from client 4 sorts (memory) 0 sorts (disk) 1000000 rows processed As you can see, that INSERT generated about 122MB of redo; we were expecting that because of the prior example in PL/SQL.
UPC - 13 Printer In Java
Using Barcode generation for Eclipse BIRT Control to generate, create EAN 13 image in Eclipse BIRT applications.
www.OnBarcode.com
Generate EAN-13 Supplement 5 In Objective-C
Using Barcode generator for iPad Control to generate, create GS1 - 13 image in iPad applications.
www.OnBarcode.com
Note The example in this section was performed on a NOARCHIVELOG-mode database. If you are in ARCHIVELOG
Drawing Code 128 Code Set C In .NET Framework
Using Barcode generation for ASP.NET Control to generate, create Code 128 Code Set C image in ASP.NET applications.
www.OnBarcode.com
EAN-13 Supplement 5 Reader In None
Using Barcode reader for Software Control to read, scan read, scan image in Software applications.
www.OnBarcode.com
mode, the table would have to be created or set as NOLOGGING to observe this dramatic change. We will investigate the NOLOGGING attribute in more detail shortly in the section Setting NOLOGGING in SQL. Please make sure to coordinate all nonlogged operations with your DBA on a real system.
Print UPC-A In None
Using Barcode generation for Microsoft Word Control to generate, create UCC - 12 image in Word applications.
www.OnBarcode.com
QR-Code Decoder In Visual Basic .NET
Using Barcode scanner for .NET framework Control to read, scan read, scan image in VS .NET applications.
www.OnBarcode.com
When we use a direct-path load in a NOARCHIVELOG-mode database, we get the following results: ops$tkyte%ORA11GR2> truncate table t; Table truncated. ops$tkyte%ORA11GR2> insert /*+ APPEND */ into t 2 select * from big_table; 1000000 rows created. Statistics ---------------------------------------------------------2828 recursive calls 17644 db block gets 15874 consistent gets 14771 physical reads 240900 redo size 916 bytes sent via SQL*Net to client 1020 bytes received via SQL*Net from client 4 SQL*Net roundtrips to/from client 1 sorts (memory) 0 sorts (disk) 1000000 rows processed ops$tkyte%ORA11GR2> set autotrace off
Read Barcode In Visual C#.NET
Using Barcode Control SDK for .NET Control to generate, create, read, scan barcode image in Visual Studio .NET applications.
www.OnBarcode.com
Draw Code 128 Code Set B In None
Using Barcode generator for Software Control to generate, create Code 128 Code Set A image in Software applications.
www.OnBarcode.com
CHAPTER 9 REDO AND UNDO
Encode PDF 417 In Visual Basic .NET
Using Barcode encoder for Visual Studio .NET Control to generate, create PDF 417 image in .NET applications.
www.OnBarcode.com
Reading Barcode In Java
Using Barcode Control SDK for Java Control to generate, create, read, scan barcode image in Java applications.
www.OnBarcode.com
That INSERT generated only about 240KB kilobytes, not megabytes of redo. The method I outline using the V$MYSTAT view is useful in general for seeing the side effects of various options. The GET_STAT_VAL script is useful for small tests, with one or two operations.
Can I Turn Off Redo Log Generation
This question is often asked. The simple short answer is no, since redo logging is crucial for the database; it is not overhead and it is not a waste. You do need it, regardless of whether you believe you do or not. It is a fact of life, and it is the way the database works. If you turned off redo, then any temporary failure of disk drives, power, or a software crash, would render the entire database unusable and unrecoverable. That said, however, there are some operations that can be done without generating redo log in some cases.
LOGGING mode. In that case, all operations are logged. The query SELECT FORCE_LOGGING FROM V$DATABASE may be used to see if logging is going to be forced or not. This feature is in support of Data Guard, a disaster-recovery feature of Oracle that relies on redo to maintain a standby database copy.
Copyright © OnBarcode.com . All rights reserved.