On Tue, 2006-10-03 at 18:29 -0700, Tomeh, Husam wrote:
> >> * When any session updates the data that already in shared
> buffer,
> >>does Postgres synchronize the data both disk and shared buffers area
> >> immediately ?
>
> Not necessarily true. When a block is modified in the shared buffers,
> the modified block is written to the Postgres WAL log. A periodic DB
> checkpoint is performed to flush the modified blocks in the shared
> buffers to the data files.
Postgres 8.0 and beyond have a process called bgwriter that continually
flushes dirty buffers to disk, to minimize the work that needs to be
done at checkpoint time.
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TIP 9: In versions below 8.0, the planner will ignore your desire to
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