exadata wait eventleri

[ilker kaysı]

Merhaba Erman bey,

Exadata makinesi üzerinde sıklıkla gördüğümüz wait eventlerin açıklanması konusunda desteğinizi rica edebilir miyiz. Aşağıdaki eventlerin kısa açıklamaları bizler için yeterlidir.


cell list of blocks physical read
cell multiblock physical read  
cell single block physical read  
cell smart table scan    
cell smart index scan    

teşekkürler.

[ErmanArslansOracleBlog]

Cell Smart Table scan : is the event that occurs during a smart scan on a Table.
Cell Smart Index Scan : is the event that occurs during a smart scan on an index.
cell single block physical read  : is the event that mostly occours on normal index I/O - access, conventional, not offloaded, not Exadata style. You may see this wait high on OLTP envs.. But on DWH we normally expect to see this way low.
cell multiblock physical read: is the event that you see a normal full table scan , again not exadata style access.. You may also see this event on a conventional Index Fast Full Scan -- not offloaded ones..
cell list of blocks physical read:
cell list of blocks physical read :   It the wait event similar to db file parallel read. It is seen while performing multiple & asynchronous single block reads.. You may see it while performing ops like index range scans