| checkpoint time [message #205673] |
Mon, 27 November 2006 01:09  |
timurgokce
Messages: 1
Registered: November 2006
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Junior Member |
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During a checkpoint the following occurs:
- The database writer (DBWR) writes all modified database
blocks in the buffer cache back to datafiles,
- Log writer (LGWR) updates both the controlfile and
the datafiles to indicate when the last checkpoint
occurred (SCN)
Checkpoint process updates the file headers of the data files and flushes the dirty buffers in cache to data files.
i) Is there any propotional relation between "number of datafiles" and time spent to perform a checkpoint ?
ii) Is the majority of the time spent to checkpoint caused by "header update" or "flushing dirty buffers" ?
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| Re: checkpoint time [message #205698 is a reply to message #205673] |
Mon, 27 November 2006 03:16  |
bwetkstr
Messages: 114
Registered: August 2005
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Senior Member |
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Hello,
I think he has to set a checkpoint in every datafile, so normally the more datafiles you have the longer this wil take. But I don't think it will slow down your system just by adding a new datafile. If that is what you are asking.
And I think it is fair to say that the most time consuming action of checkpointing is flushing the buffers and updating the headers.
Kr
Karel.
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