Home » Other » General » Redo Log Buffer Quick Question (Oracle Database 12c Enterprise Edition Release 12.1.0.2.0)
Redo Log Buffer Quick Question [message #672780] Fri, 26 October 2018 08:57 Go to next message
wtolentino
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The log writer LGWR is the background process that transfers all undo and redo entries in the log buffer to the redo log files. What is the server or background process that puts the undo and redo entries to the Redo Log Buffer.

Thanks,
Warren
Re: Redo Log Buffer Quick Question [message #672782 is a reply to message #672780] Fri, 26 October 2018 09:04 Go to previous messageGo to next message
John Watson
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Quote:
transfers all undo and redo entries in the log buffer to the redo log files
No! Redo is change vectors applied to blocks: table blocks, index blocks, undo blocks, all sorts of blocks. A change to an undo block is no different to a change to any other type of block.


Quote:
What is the server or background process that puts the undo and redo entries to the Redo Log Buffer.
It is the session server process: the process that is doing your DML.
Re: Redo Log Buffer Quick Question [message #672789 is a reply to message #672782] Fri, 26 October 2018 10:30 Go to previous messageGo to next message
wtolentino
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John Watson wrote on Fri, 26 October 2018 10:04
It is the session server process: the process that is doing your DML.

thanks. is that the same as the client process or differrent process. i was looking at the oracle 12c database architechture diagram (print) but could not find it.

[Updated on: Fri, 26 October 2018 10:34]

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Re: Redo Log Buffer Quick Question [message #672790 is a reply to message #672789] Fri, 26 October 2018 10:31 Go to previous messageGo to next message
John Watson
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The client process is not the same as the server process.
Re: Redo Log Buffer Quick Question [message #672791 is a reply to message #672790] Fri, 26 October 2018 10:44 Go to previous messageGo to next message
wtolentino
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thank you. can you help point exactly what is that process in the oracle 12c database architecture diagram. for example LGWR, CKPT, DBWr, ARCHn.
Re: Redo Log Buffer Quick Question [message #672793 is a reply to message #672791] Fri, 26 October 2018 10:57 Go to previous messageGo to next message
Michel Cadot
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Database Concepts, Chapter 15 Process Architecture.

Re: Redo Log Buffer Quick Question [message #672801 is a reply to message #672793] Fri, 26 October 2018 12:11 Go to previous messageGo to next message
wtolentino
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thanks Michel. yes I looked up also into that documentation prior to posting my question in here and re-read it again. maybe I a missing something or not fully understand the terminology and still could not find that "session server process" that John Watson mentioned.
Re: Redo Log Buffer Quick Question [message #672804 is a reply to message #672801] Fri, 26 October 2018 12:21 Go to previous messageGo to next message
Michel Cadot
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In the red square in the image taken from the page I pointed you to.

/forum/fa/13960/0/

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Re: Redo Log Buffer Quick Question [message #672805 is a reply to message #672804] Fri, 26 October 2018 12:31 Go to previous message
wtolentino
Messages: 301
Registered: March 2005
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thanks so much now I understand. it was not something that i thought there's a "session server process" that is totally different from the "server process". the 2 can be sometimes interchangeably called.
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