Oracle performans yenilikleri:SQL result Cache

Istedigimiz bazi sorgularin sonuclari diskten fiziksel I/O yapmaktansa memoryden getirebilme yeniligidir. Boylece fiziksel I/O nun neden oldugu Cpu artislarinada bir onlem almis oluruz.
Result cache query’in sonuclarini butun sessionlarin ortak kullanimina acar.aslinda client side ve
server side olarak birbirinden ayirmak lazimdir.Client tarafinda SGA kullanilmaz.
Result_cache_mode diye yeni bir parametremiz gelmistir. Bu parametre Manuel ve force olmak uzere iki secenekten olusur. Manuel modda /*+result_cache */ hintini kullanmamiz lazimdir.
Select /*+ result_cache */ job_id,max(salary) from employees group by job_id gibi

force modda ise otomatik olarak sql result cache kullanilir.
Force modda kullanmak istemezsek /*+no_result_cache*/ hinti tercih edilebilir.
CLIENT_RESULT_CACHE_SIZE parametresi ile clientlarin ne kadar result cache sahip olacaklarina karar verebiliriz. 0 olmasi disabled olmasi anlamına gelir.

CLIENT_RESULT_CACHE_LAG parametresi ilede ayrica clientlarin ne kadar sıklıkta veritabanı ile sekronize olmasini saglariz.

Tabiki boyle bir ozelliginde CLIENT_RESULT_CACHE_STATS$ monitor edilmesi mumkundur.

SQL> set serveroutput on
SQL> execute dbms_result_cache.memory_report
R e s u l t C a c h e M e m o r y R e p o r t
Block Size = 1024 bytes
Maximum Cache Size = 950272 bytes (928 blocks)
Maximum Result Size = 47104 bytes (46 blocks)
Total Memory = 46340 bytes [0.048% of the Shared Pool]
... Fixed Memory = 10696 bytes [0.011% of the Shared Pool]
... State Object Pool = 2852 bytes [0.003% of the Shared Pool]
... Cache Memory = 32792 bytes (32 blocks) [0.034% of the Shared Pool]
....... Unused Memory = 30 blocks
....... Used Memory = 2 blocks
........... Dependencies = 1 blocks

........... Results = 1 blocks
............... SQL = 1 blocks

PL/SQL procedure successfully completed.

To remove all existing results and clear the cache memory, use the command:

SQL>execute dbms_result_cache.flush

select name, value from v$result_cache_statistics;

The output of this query will be similar to the following:

NAME                          VALUE
-------------------- ----------
Block Size (Bytes) 1024
Block Count Maximum 3136
Block Count Current 32
Result Size Maximum (Blocks) 156
Create Count Success 2
Create Count Failure 0
Find Count 0
Invalidation Count 0
Delete Count Invalid 0
Delete Count Valid 0

Block Size (Bytes)

her memory blogunun size

Block Count Maximum

max izin vereilen memory block sayisi

Block Count Current

suanda nekadar memeory blogu ayrıldıgı

Result Size Maximum (Blocks)

tekbir result cache max. nekadar ayrıldıgı

Create Count Success

kac kere basarılı bir sekilde result cache yaratıldı

Create Count Failure

kac kere fail etti

Find Count

Kac kere basarılı bir sekilde result cache bulundu

Invalidation Count

invalidation sayısı

Delete Count Invalid

silinen invalid cache

Delete Count Valid

silinen valid cache

bir sistemin SQL query result cache iyi kullandıgının gostergesi Create Count Failure ve Delete Count Valid dusuk olmasidir ve find countun yuksek olmasıdır.

About oracledocuments

Zekeriya Beşiroğlu, It joined the Bilginc IT Academy in July 2000. In the meantime, the Oracle Education, Oracle Data Base Management System and Oracle Internet Technologies, Oracle development technologies such as the training of Oracle products is responsible for training as consultants. During this task, since 1 April 2008 with 293 Oracle training in total, in 2150 Oracle customers successfully submitted. Oracle 10g New York in November 2002 have received training and education in Turkey was the first time the consultants. 20 April 2008 on education in Turkey 11g is the first who was a consultant. Oracle Real Application Cluster Expert advisor is certified is the first . Http:// and Http:// owner and manager of the site. Its own has more than one hundred articles. In addition, creation and improvement of training materials are also related to work. Oracle products are used, database management and reporting Academy eruditely It also is working on. From the date of 1 January 2009 will continue to work as the Technical Director
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