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Oracle insert transaction - what process reads free blocks?

peter_strauss
Participant
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Hello,

I have before me the Oracle insert process described as:

1. Read the data from the data file

2. Read a block from the rollback segment

3. Write redo information that specifies the change to the rollback block

4. Copy the old data block value to the rollback data block

5. Write redo information concerning the changes to the table data block

6. Change the table data block

At steps 1 and 2 is the reading done by the shadow process (I guess it has to be the shadow process, but can someone please confirm).

Kind regards,

Peter

Accepted Solutions (1)

Accepted Solutions (1)

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Hi Peter,

Probably you should check the <a href="http://download.oracle.com/docs/cd/B19306_01/server.102/b14220/toc.htm">Oracle Concepts Guide</a>

Not sure if it explains it on detail.

The answer to your questions is "yes", the oracle shadow process tries to fulfill the client request. If the data is not on the buffer already, it is retrieved by the shadow process from disk.

peter_strauss
Participant
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Thanks!

Sorry, I think I'm starting to abuse the system here. It's very helpful though.

I'll press on with the slides I have before me, and otherwise check the concepts guide.

Regards,

Peter

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Hi,

IMHO,

There is a difference between "trying to understand" questions and "give me the solution" questions.

You are following some slides and you do not understand something. That is normal, nobody knows all. Doubts appear. You "research" and you do not find the solution or do not understand it. Use the forum, it is here for that. Perhaps the answer is on the manual, note ... and someone will point it to that.

Unfortunately, there are other "users" that do not bother trying to find the solution, read the manual ... They have a problem and <i>demand </i>an answer immediately, or they have a job interview in 1/2 hour and they try to "find" the answer without any effort.

The answer could be the same as in the previous case, but perhaps it is not so useful.

Answers (1)

Answers (1)

peter_strauss
Participant
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Sorry, please don't bother answering (unless you want some quick points). The very next slide says "All six steps were performed by the shadow process".