Re: increasing the default WAL segment size

Hello,

Thank you for your comments, I will post an updated patch soon.

On Fri, Mar 17, 2017 at 6:40 AM, Robert Haas <robertmhaas(at)gmail(dot)com> wrote:
>
>
> +assign_wal_segment_size(int newval, void *extra)
>
> Why does a PGC_INTERNAL GUC need an assign hook? I think the GUC
> should only be there to expose the value; it shouldn't have
> calculation logic associated with it.
>

The Checkpoint Segments and the UsableBytesInSegment had to be changed
depending on the value of wal_segment_size set during initdb. I will
figure out another way to assign these values without using this
assign_hook.

> + wal_segment_size = atoi(str_wal_segment_size);
>
> So, you're comfortable interpreting --wal-segsize=1TB or
> --wal-segsize=1GB as 1? Implicitly, 1MB?
>

The option was intended to only accept values in MB as the original config
--with-wal-segsize option, unfortunately, the patch does not throw error as
in the config option when the units are specified.

Error with config option --with-wal-segsize=1MB
configure: error: Invalid WAL segment size. Allowed values are
1,2,4,8,16,32,64.

Should we imitate this behaviour and just add a check to see if it only
contains numbers? or would it be better to allow the use of the units and
make appropriate code changes?

--
Thank you,

Beena Emerson

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