Re: Sequence of processing: WAL / shared buffers

Hi Jurgen,

If synchronous_commit is enabled, transaction commit will wait for WAL
records to be written to disk before the command returns a "success" indication
to the client. Shared buffers is not involved when commit is issued. For
flushing of shared buffers to data files, we can use checkpoint instead.
BGWR in charge of writing shared_buffers to the datafiles.

Thanks!

On 28 January 2016 at 19:49, Jürgen Purtz <juergen(at)purtz(dot)de> wrote:

> Hi,
>
> can anyone explain, what happens first during an UPDATE of an indexed
> column: writing and flushing to WAL or modification of shared buffers? And:
> both actions are finished before a confirmation is send to the requesting
> client - or?
>
> Regards, Jürgen Purtz
>
>
>
>
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Regards,
Ang Wei Shan