Re: Does an ALTER SYSTEM CHKPOINT write all dirty buffers to datafiles ?

I have in front of me the Oracle University course book Enterprise DBA Part 1A: Architecture and Administration. In lesson 7, Maintaining Redo Log Files, page 7-7, it reads:
> Checkpoints
> During a checkpoint:
> o A number of dirty database buffers covered by the log being
> checkpointed are written to the data files by DBWn. The number
> of buffers being written by DBWn is determined by the parameter
> FAST_START_IO_TARGET, if specified. [...]
> o the checkpoint background process CKPT updates the headers of
> all data files and controlfiles to reflect that it has completed
> successfully.
> Checkpoints can occur for *all* data files in the DB or for only
> *specific* data files.

(words between '*' mean they appear in italics in the text) So: "a number of dirty DB buffers" doesn't mean ALL DB buffers, and "checkpoints can occur for *all* data files .. or for only *specific*" ones... Hence my question. In fact I should've stressed 'all' in my subject line, and not uppercased ALTER SYSTEM CHKPOINT ! Besides, a checkpoint is associated to the log group ("dirty DB buffers covered by the log being checkpointed...").

richard.foote_at_bigpond.com (Richard Foote) wrote...
> ...
> It's the "CKPT process" that only writes to the datafile headers (and
> control files).
>
> Possibly the cause for the confusion ?
>
> Cheers
>
> Richard
Received on Thu Jul 17 2003 - 07:35:03 CDT