Re: configure option for XLOG_BLCKSZ

On Fri, May 2, 2008 at 12:04 AM, Joshua D. Drake <jd(at)commandprompt(dot)com> wrote:
>
> Tom Lane wrote:
>
> > "Mark Wong" <markwkm(at)gmail(dot)com> writes:
> >
> > > I saw a that a patch was committed that exposed a configure switch for
> > > BLCKSZ. I was hoping that I could do that same for XLOG_BLCKSZ.
> > >
> >
> > Well, we certainly *could*, but what's the use-case really? The case
> > for varying BLCKSZ is marginal already, and I've seen none at all for
> > varying XLOG_BLCKSZ. Why do we need to make it easier than "edit
> > pg_config_manual.h"?
> >
>
> The use case I could see is for performance testing but I would concur that
> it doesn't take much to modify pg_config_manual.h. In thinking about it,
> this might actually be a foot gun. You have a new pg guy, download source
> and think to himself..., "Hey I have a 4k block size as formatted on my hard
> disk". Then all of a sudden they have an incompatible PostgreSQL with
> everything else.

As someone who has tested varying both those parameters it feels
awkward to have a configure option for one and not the other, or vice
versa. I have slightly stronger feelings for having them both as
configure options because it's easier to script, but feel a little
more strongly about having BLCKSZ and XLOG_BLCKSZ both as either
configure options or in pg_config_manual.h. To have them such that
one needs to change them in different manners makes a tad more work in
automating testing. So my case is just for ease of testing.

Regards,
Mark