Time of reading block from disk

Hello !
Before block will be read into buffer cashe
these processes takes place :
1) searching of the current version of block ,
2) searching of free space
Does "db file sequential(scattered) read" includes this wait events ?
Thanks and regards,
Pavel

Pavel wrote:
Hello !
Before block will be read into buffer cashe
these processes takes place :
1) searching of the current version of block ,
2) searching of free space
Does "db file sequential(scattered) read" includes this wait events ?The scan is going to look up for the free buffers in the buffer cache. What you are referring to here is the scan of the accessed buffers if I am getting it correctly. If there is a lot of wait on the CBC LRU Chain Latch and/or the wait event, "free buffer wait" is reported than you are looking for the reading of the blocks into the buffers of the buffer cache. Even then, increasing the cache should not be a solution that you should think about right away. How about a situation where your all queries are going for FTS?
And for the understanding of how the buffer processing happens when you ask for a buffer lookup, I think this should be helpful,
http://asktom.oracle.com/pls/apex/f?p=100:11:0::::P11_QUESTION_ID:2424130600346937669
HTH
Aman....

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[root@:/root]# uname -a
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sorry...
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Attachments:
test11.vi ‏130 KB

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