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Is non full (lesser than size of the log_buffer) redo is resumed after forceful log switch? [message #520551]

Tue, 23 August 2011 07:05

swaorclser
Messages: 56
Registered: August 2011

Member

hello,

Just wanted to know if I do

ALTER SYSTEM ARCHIVE LOG CURRENT;

Then it archives the current redo and switches to next redo.

If again switching is done, then just wanted to know if redo is archived when its size is less than log_buffer, then is it resumed when it is switched into next time or after archiving it creates a empty redo file and then use it?

Thanks & regards,
swaorclser

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Re: Is non full (lesser than size of the log_buffer) redo is resumed after forceful log switch? [message #520552 is a reply to message #520551]

Tue, 23 August 2011 07:12

Michel Cadot
Messages: 68775
Registered: March 2007
Location: Saint-Maur, France, https...

Senior Member
Account Moderator

I think you mix up several things.
1/ log buffer is filled by processes
2/ Sometime log buffer is flushed into a log file
3/ Sometime (or when asked) log file is switched
4/ After log file was switched, some time later, log file is archived.

ALTER SYSTEM SWITCH LOGFILE stops current log file filling, switch to the next log file AND signals ARCH process to archive the previous log file.
ALTER SYSTEM ARCHIVE LOG CURRENT stops current log file filling, switch to the next log file AND archive the previous log file.

Regards
Michel

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Re: Is non full (lesser than size of the log_buffer) redo is resumed after forceful log switch? [message #520555 is a reply to message #520552]

Tue, 23 August 2011 07:30

swaorclser
Messages: 56
Registered: August 2011

Member

Hello!

Thank you for your reply Michel!

Whenever any redo is archived, it becomes some file like xxx.arc and is stored in destinations specified.

Suppose I have three redo files group with one redo in each.
Now if redo1 is archived, then is this file again created or same file is continued till its size limit is met and first_change field is changed ?

I am not good at putting my problem into words.
Please accept my apologies for the same.

Thanks & Regards,
swaorclser

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Re: Is non full (lesser than size of the log_buffer) redo is resumed after forceful log switch? [message #520563 is a reply to message #520555]

Tue, 23 August 2011 08:25

Michel Cadot
Messages: 68775
Registered: March 2007
Location: Saint-Maur, France, https...

Senior Member
Account Moderator

Quote:

Now if redo1 is archived, then is this file again created or same file is continued till its size limit is met and first_change field is changed ?

Log file is reused from beginning. File size never changes, content is overwritten, a tag indicates the end of the data when the log is switched.

Regards
Michel

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