Re: Forcing current WAL file to be archived

Ühel kenal päeval, K, 2006-08-09 kell 12:56, kirjutas Simon Riggs:
> On Sat, 2006-08-05 at 23:57 -0400, Tom Lane wrote:
>
> > I also made the new user-level functions a bit
> > more orthogonal, so that filenames could be extracted from the
> > existing functions like pg_stop_backup.
>
> Something Hannu wrote has just reminded me that
> pg_current_xlog_location() returns the current Insert pointer rather
> than the current Write pointer.
>
> That would not be useful for streaming xlog records would it?
>
> Methinks it should be the Write pointer all of the time, since I can't
> think of a valid reason for wanting to know where the Insert pointer is
> *before* we've written to the xlog file. Having it be the Insert pointer
> could lead to some errors.
>
> Any objections if I correct that?

What is the difference ?

I'd expect it to point either to last byte written or to the next byte
that will be written, and I want to know which one it is :)

And another question:

is is possible that under some circumstances the last few bytes of a WAL
file will not be written to ?

or is the writing done as if all the wal files together form one huge
tape, without any gaps between ?

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Hannu Krosing
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