| tablespace backup mode [message #58061] |
Tue, 29 July 2003 04:39  |
shyam
Messages: 25
Registered: January 2001
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Junior Member |
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hi
what will happen when a tablespace taken to backup mode.whether users have any restrictions to access the
dataobjects of the tablespace.Why extra redo is generating when taking a tablespace backup mode
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| Re: tablespace backup mode [message #58062 is a reply to message #58061] |
Tue, 29 July 2003 06:06  |
Uwe
Messages: 260
Registered: February 2003
Location: Zürich, Switzerland
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Senior Member |
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The Tablespace is freezed, but all actions are stored in the redo-logs. After putting tablespace out of backup Oracle take care for doing all stored actions to that tablespace. Oracle managed this by the sequence-numbers each action will get.
hth
Uwe
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| Re: tablespace backup mode [message #58133 is a reply to message #58062] |
Mon, 04 August 2003 06:58 |
Deepa
Messages: 269
Registered: November 2000
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Senior Member |
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The tablespace is not freezed during a hotbackup.
Just the DatafileHeaders are freezed with the SCN at the time of beginbackup.the datafiles are updated like normal, only the file header blocks are not updated for checkpoint activity.
When you end the backup Oracle updates the header for the last checkpoint and then knows the tablespace is consistent with this point in time.
When the datafile is restored from a hot
backup, the recovery will begin from the SCN captured during the begin backup
is issued. All changes applied during the hot backup time period will be
rolled forward from the redo logs.
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